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1.  A Prospective Study of Plasma Vitamin D Metabolites, Vitamin D Receptor Polymorphisms, and Prostate Cancer 
PLoS Medicine  2007;4(3):e103.
Vitamin D insufficiency is a common public health problem nationwide. Circulating 25-hydroxyvitamin D3 (25[OH]D), the most commonly used index of vitamin D status, is converted to the active hormone 1,25 dihydroxyvitamin D3 (1,25[OH]2D), which, operating through the vitamin D receptor (VDR), inhibits in vitro cell proliferation, induces differentiation and apoptosis, and may protect against prostate cancer. Despite intriguing results from laboratory studies, previous epidemiological studies showed inconsistent associations of circulating levels of 25(OH)D, 1,25(OH)2D, and several VDR polymorphisms with prostate cancer risk. Few studies have explored the joint association of circulating vitamin D levels with VDR polymorphisms.
Methods and Findings
During 18 y of follow-up of 14,916 men initially free of diagnosed cancer, we identified 1,066 men with incident prostate cancer (including 496 with aggressive disease, defined as stage C or D, Gleason 7–10, metastatic, and fatal prostate cancer) and 1,618 cancer-free, age- and smoking-matched control participants in the Physicians' Health Study. We examined the associations of prediagnostic plasma levels of 25(OH)D and 1,25(OH)2D, individually and jointly, with total and aggressive disease, and explored whether relations between vitamin D metabolites and prostate cancer were modified by the functional VDR FokI polymorphism, using conditional logistic regression. Among these US physicians, the median plasma 25(OH)D levels were 25 ng/ml in the blood samples collected during the winter or spring and 32 ng/ml in samples collected during the summer or fall. Nearly 13% (summer/fall) to 36% (winter/spring) of the control participants were deficient in 25(OH)D (<20 ng/ml) and 51% (summer/fall) and 77% (winter/spring) had insufficient plasma 25(OH)D levels (<32 ng/ml). Plasma levels of 1,25(OH)2D did not vary by season. Men whose levels for both 25(OH)D and 1,25(OH)2D were below (versus above) the median had a significantly increased risk of aggressive prostate cancer (odds ratio [OR] = 2.1, 95% confidence interval [CI] 1.2–3.4), although the interaction between the two vitamin D metabolites was not statistically significant (pinteraction = 0.23). We observed a significant interaction between circulating 25(OH)D levels and the VDR FokI genotype (pinteraction < 0.05). Compared with those with plasma 25(OH)D levels above the median and with the FokI FF or Ff genotype, men who had low 25(OH)D levels and the less functional FokI ff genotype had increased risks of total (OR = 1.9, 95% CI 1.1–3.3) and aggressive prostate cancer (OR = 2.5, 95% CI 1.1–5.8). Among men with plasma 25(OH)D levels above the median, the ff genotype was no longer associated with risk. Conversely, among men with the ff genotype, high plasma 25(OH)D level (above versus below the median) was related to significant 60%∼70% lower risks of total and aggressive prostate cancer.
Our data suggest that a large proportion of the US men had suboptimal vitamin D status (especially during the winter/spring season), and both 25(OH)D and 1,25(OH)2D may play an important role in preventing prostate cancer progression. Moreover, vitamin D status, measured by 25(OH)D in plasma, interacts with the VDR FokI polymorphism and modifies prostate cancer risk. Men with the less functional FokI ff genotype (14% in the European-descent population of this cohort) are more susceptible to this cancer in the presence of low 25(OH)D status.
Results of this study by Haojie Li and colleagues suggest that vitamin D deficiency is common among men in the US, and that vitamin D status and genetic variation in theVDR gene affect prostate cancer risk.
Editors' Summary
Prostate cancer occurs when cells in the prostate gland (part of the male reproductive system) accumulate genetic changes that allow them to grow into a disorganized mass of cells. Patients whose disease is diagnosed when these cells are still relatively normal can survive for many years, but for patients with aggressive cancers—ones containing fast-growing cells that can migrate around the body—the outlook is poor. Factors that increase prostate cancer risk include increasing age, having a family history of prostate cancer, and being African American. Also, there are hints that some environmental or dietary factors affect prostate cancer risk. One of these factors is vitamin D, of which high levels are found in seafood and dairy products, but which can also be made naturally by the body—more specifically, by sunlight-exposed skin. One reason researchers think vitamin D might protect against prostate cancer is that this cancer is more common in sun-starved northern countries (where people often have a vitamin D deficiency) than in sunny regions. Prostate cancer is also more common in African American men than in those of European descent (when exposed to the same amount of sunlight, individuals with darker skin make less vitamin D than those with lighter skin). Once in the human body, vitamin D is converted into the vitamin D metabolite 25-hydroxyvitamin D3 (25[OH]D) and then into the active hormone 1,25 dihydroxyvitamin D3 (1,25[OH]2D). This binds to vitamin D receptors (VDRs) and inhibits cell proliferation and migration.
Why Was This Study Done?
The effect of 1,25(OH)2D on cells and the observation that related chemicals slow prostate cancer growth in rodents suggest that vitamin D protects against prostate cancer. But circulating levels of vitamin D metabolites in human male populations do not always reflect how many men develop prostate cancer. This lack of correlation may partly be because different forms of the VDR gene exist. One area of variation in the VDR gene is called the FokI polymorphism. Because everyone carries two copies of the VDR gene, individuals may have a FokI FF, FokI Ff, or FokI ff genotype. The f variant (or allele) codes for a receptor that is less responsive to 1,25(OH)2D than the receptor encoded by the FokI F allele. So levels of vitamin D sufficient to prevent cancer in one person may be insufficient in someone with a different FokI genotype. In this study, the researchers have investigated how levels of 25(OH)D and 1,25(OH)2D in combination with different VDR FokI alleles are influencing prostate cancer risk.
What Did the Researchers Do and Find?
The researchers identified 1,066 men who developed prostate cancer between enrollment into the US Physicians' Health Study in 1982 and 2000, and 1,618 cancer-free men of the same ages and smoking levels as “controls.” They measured vitamin D metabolite levels in many of the blood samples taken from these men in 1982 and determined their FokI genotype. Two-thirds of the men had insufficient blood levels of vitamin D metabolites in the winter/spring; almost one-third had a vitamin D deficiency. Men whose blood levels of both metabolites were below average were twice as likely to develop aggressive prostate cancer as those in whom both levels were above average. Compared with men with high blood levels of 25(OH)D and the FokI FF or Ff genotype, men with low 25(OH)D levels and the FokI ff genotype were 2.5 times as likely to develop aggressive prostate cancer. However, men with the ff genotype were not at higher risk if they had sufficient 25(OH)D levels. Among men with the ff genotype, sufficient 25(OH)D levels might therefore protect against prostate cancer, especially against the clinically aggressive form.
What Do These Findings Mean?
These findings confirm that many US men have suboptimal levels of circulating vitamin D. This vitamin is essential for healthy bones, so irrespective of its effects on prostate cancer, vitamin D supplements might improve overall health. In addition, this large and lengthy study reveals an association between low levels of the two vitamin D metabolites and aggressive prostate cancer that is consistent with vitamin D helping to prevent the progression of prostate cancer. It also indicates that the VDR FokI genotype modifies the prostate cancer risk associated with different blood levels of vitamin D. Together, these results suggest that improving vitamin D status through increased exposure to sun and vitamin D supplements might reduce prostate cancer risk, particularly in men with the FokI ff genotype. Because the study participants were mainly of European descent, the researchers caution that these results may not apply to other ethnic groups and note that further detailed studies are needed to understand fully how vitamin D affects prostate cancer risk across the population.
Additional Information.
Please access these Web sites via the online version of this summary at
MedlinePlus encyclopedia has pages on prostate cancer and on vitamin D
Information for patients and physicians is available from the US National Cancer Institute on prostate cancer and on cancer prevention
The Prostate Cancer Foundation's information on prostate cancer discusses the effects of nutrition on the disease
Patient information on prostate cancer is available from Cancer Research UK
Cancerbackup also has patient information on prostate cancer
PMCID: PMC1831738  PMID: 17388667
2.  Sun Protection Counseling by Pediatricians has Little Effect on Parent and Child Sun Protection Behavior 
The Journal of pediatrics  2012;162(2):381-386.
To compare counseling concerning sun protection and outdoor exercise with the parent’s report of the behavior of a child age 9 to 16 years old.
Study design
Structured interviews of medical personnel in three Chicago area practices elicited information about counseling methods and recommendations. In each practice, a convenience sample of parents completed a self-reported survey of their and their child’s behavior.
Sun protection counseling occurred more frequently than exercise counseling in all practices (p=0.014). Sun protection counseling was associated with parental prompting (p =0.004), performing a summer camp physical (p=0.002), and the child having a sunburn (p=0.003). After controlling for the child’s age, sex, and skin tone, sun protection counseling was not associated with the child’s use of sun protection. In multivariate analysis of the child’s sun protection behavior, parental sunburns, indoor tanning in the last 12 months, perception of skin cancer risk and sun protection self-efficacy were significant. (p=.02) Children who pursued outdoor sports were twice as likely to use inadequate sun protection and sustain sunburns. (CI 1.3–1.7)
The child’s sun protection behavior was influenced by parental sun protection, parental perception of skin cancer risk and parental sun protection self-efficacy; therefore, sun protection for children needs to be aimed at parents as well as children. Communication with parents in a way that incorporates the principles of motivational interviewing may be more effective in promoting behavioral change than admonitions to use sunscreen.
PMCID: PMC3547152  PMID: 22954897
Skin cancer prevention; outdoor exercise; sun protection; counseling by pediatricians
3.  Vitamin K Supplementation in Postmenopausal Women with Osteopenia (ECKO Trial): A Randomized Controlled Trial 
PLoS Medicine  2008;5(10):1-12.
Vitamin K has been widely promoted as a supplement for decreasing bone loss in postmenopausal women, but the long-term benefits and potential harms are unknown. This study was conducted to determine whether daily high-dose vitamin K1 supplementation safely reduces bone loss, bone turnover, and fractures.
Methods and Findings
This single-center study was designed as a 2-y randomized, placebo-controlled, double-blind trial, extended for earlier participants for up to an additional 2 y because of interest in long-term safety and fractures. A total of 440 postmenopausal women with osteopenia were randomized to either 5 mg of vitamin K1 or placebo daily. Primary outcomes were changes in BMD at the lumbar spine and total hip at 2 y. Secondary outcomes included changes in BMD at other sites and other time points, bone turnover markers, height, fractures, adverse effects, and health-related quality of life. This study has a power of 90% to detect 3% differences in BMD between the two groups. The women in this study were vitamin D replete, with a mean serum 25-hydroxyvitamin D level of 77 nmol/l at baseline. Over 2 y, BMD decreased by −1.28% and −1.22% (p = 0.84) (difference of −0.06%; 95% confidence interval [CI] −0.67% to 0.54%) at the lumbar spine and −0.69% and −0.88% (p = 0.51) (difference of 0.19%; 95% CI −0.37% to 0.75%) at the total hip in the vitamin K and placebo groups, respectively. There were no significant differences in changes in BMD at any site between the two groups over the 2- to 4-y period. Daily vitamin K1 supplementation increased serum vitamin K1 levels by 10-fold, and decreased the percentage of undercarboxylated osteocalcin and total osteocalcin levels (bone formation marker). However, C-telopeptide levels (bone resorption marker) were not significantly different between the two groups. Fewer women in the vitamin K group had clinical fractures (nine versus 20, p = 0.04) and fewer had cancers (three versus 12, p = 0.02). Vitamin K supplements were well-tolerated over the 4-y period. There were no significant differences in adverse effects or health-related quality of life between the two groups. The study was not powered to examine fractures or cancers, and their numbers were small.
Daily 5 mg of vitamin K1 supplementation for 2 to 4 y does not protect against age-related decline in BMD, but may protect against fractures and cancers in postmenopausal women with osteopenia. More studies are needed to further examine the effect of vitamin K on fractures and cancers.
Trial registration: (#NCT00150969) and Current Controlled Trials (#ISRCTN61708241)
Angela Cheung and colleagues investigate whether vitamin K1 can prevent bone loss among postmenopausal women with osteopenia.
Editors' Summary
Osteoporosis is a bone disease in which the bones gradually become less dense and more likely to break. In the US, 10 million people have osteoporosis and 18 million have osteopenia, a milder condition that precedes osteoporosis. In both conditions, insufficient new bone is made and/or too much old bone is absorbed. Although bone appears solid and unchanging, very little bone in the human body is more than 10 y old. Old bone is continually absorbed and new bone built using calcium, phosphorous, and proteins. Because the sex hormones control calcium and phosphorous deposition in the bones and thus bone strength, the leading cause of osteoporosis in women is reduced estrogen levels after menopause. In men, an age-related decline in testosterone levels can cause osteoporosis. Most people discover they have osteoporosis only when they break a bone, but the condition can be diagnosed and monitored using bone mineral density (BMD) scans. Treatments can slow down or reverse bone loss (antiresorptive therapies) and some (bone formation therapies) can even make bone and build bone tissue.
Why Was This Study Done?
Although regular exercise and a healthy diet can help to keep bones strong, other ways of preventing osteoporosis are badly needed. Recently, the lay media has promoted vitamin K supplements as a way to reduce bone loss in postmenopausal women. Vitamin K (which is found mainly in leafy green vegetables) is required for a chemical modification of proteins called carboxylation. This modification is essential for the activity of three bone-building proteins. In addition, there is some evidence that low bone density and fractures are associated with a low vitamin K intake. However, little is known about the long-term benefits or harms of vitamin K supplements. In this study, the researchers investigate whether a high-dose daily vitamin K supplement can safely reduce bone loss, bone turnover, and fractures in postmenopausal women with osteopenia in a randomized controlled trial called the “Evaluation of the Clinical Use of Vitamin K Supplementation in Post-Menopausal Women With Osteopenia” (ECKO) trial.
What Did the Researchers Do and Find?
In the study, 440 postmenopausal women with osteopenia were randomized to receive 5mg of vitamin K1 (the type of vitamin K in North American food; the recommended daily adult intake of vitamin K1 is about 0.1 mg) or an inactive tablet (placebo) daily for 2 y; 261 of the women continued their treatment for 2 y to gather information about the long-term effects of vitamin K1 supplementation. All the women had regular bone density scans of their lower back and hips and were examined for fractures and for changes in bone turnover. After 2 y and after 4 y, lower back and hip bone density measurements had decreased by similar amounts in both treatment groups. The women who took vitamin K1 had 10-fold higher amounts of vitamin K1 in their blood than the women who took placebo and lower amounts of a bone formation marker; the levels of a bone resorption marker were similar in both groups. Over the 4-y period, fewer women in the vitamin K group had fractures (nine versus 20 women in the placebo group), and fewer had cancer (three versus 12). Finally, vitamin K supplementation was well tolerated over the 4-y period and adverse health effects were similar in the two treatment groups.
What Do These Findings Mean?
These findings indicate that a high daily dose of vitamin K1 provides no protection against the age-related decline in bone density in postmenopausal women with osteopenia, but that vitamin K1 supplementation may protect against fractures and cancers in these women. The apparent contradiction between the effects of vitamin K1 on bone density and on fractures could mean that vitamin K1 supplements strengthen bone by changing factors other than bone density, e.g., by changing its fine structure rather than making it denser. However, because so few study participants had fractures, the difference in the fracture rate between the two treatment groups might have occurred by chance. Larger studies are therefore needed to examine the effect of vitamin K1 on fractures (and on cancer) and, until these are done, high-dose vitamin K1 supplementation should not be recommended for the prevention of osteoporosis.
Additional Information.
Please access these Web sites via the online version of this summary at
The US National Institute of Arthritis and Musculoskeletal and Skin Diseases provides detailed information about osteoporosis (in English and Spanish) and links to other resources, including an interactive web tool called Check Up On Your Bones
MedlinePlus provides links to additional information about osteoporosis (in English and Spanish)
The MedlinePlus Encyclopedia has a page about vitamin K
The UK Food Standards Agency provides information about vitamin K
Full details about the ECKO trial are available on the Web site
The Canadian Task Force for Preventive Health Care provides recommendations on the prevention of osteoporosis and osteoporotic fractures in postmenopausal women
Osteoporosis Canada provides information on current topics related to osteoporosis
PMCID: PMC2566998  PMID: 18922041
4.  Knowledge and attitudes to vitamin D and sun exposure in elite New Zealand athletes: a cross-sectional study 
Sun safety and vitamin D status are important for prolonged health. They are of particular interest to those working with athletes for whom for whom safe sun practices maybe limited.
The aim of this cross-sectional study was to describe the attitudes of elite New Zealand athletes to both vitamin D and sun exposure.
110 elite New Zealand outdoor athletes volunteered to participate in an interview with a trained interviewer. The interviewer asked the athletes questions on their Vitamin D knowledge, attitudes and practices regarding sun exposure as well as their concerns about skin cancer.
Athletes were more concerned about their risk of skin cancer (66%) than their vitamin D status (6%). Although the majority (97%) were aware of Vitamin D and could identify the sun as a source (76%) only 17% could name another source of Vitamin D.
Only 10 (9%) reported always applying sunscreen before going out in the sun. No athlete reported reapplying sunscreen every hour and 25 suggesting that they never reapply sunscreen.
Athletes are concerned about skin cancer however, their use of sunscreen is not optimal suggesting reapplication of sunscreen could be targeted in order to reduce the risk of sun cancer. Awareness of sources of Vitamin D other than the sun may also need to be improved potentially through educational interventions and possibly in conjunction with sun smart messages.
PMCID: PMC4172920  PMID: 25253998
Sun exposure; Cancer; Vitamin D; Athletes
5.  Knowledge of vitamin D and perceptions and attitudes toward sunlight among Chinese middle-aged and elderly women: a population survey in Hong Kong 
BMC Public Health  2006;6:226.
Physical and biological risk factors for vitamin D inadequacy are known; however, cultural- and population-specific behaviours and attitudes that influence these risk factors, particularly among Asian people, are less well documented. To understand more about prevailing attitudes and behaviour toward sunlight and knowledge of vitamin D among a population at greater risk of impaired vitamin D status, poor bone health and osteoporosis, we conducted a telephone interview survey of 547 middle-aged and elderly Chinese women living in Hong Kong.
All telephone interviews were conducted using the Computer Assisted Telephone Technique and target respondents were selected by random sampling. Interviews were conducted in Cantonese and eighteen main questions were asked pertaining to personal characteristics, perceptions, attitudes and behaviour toward sunlight, and knowledge about vitamin D.
The survey results showed that 62.3% (n = 341) did not like going in the sun and 66.7% of respondents spent an average of 6–10 hours indoors, between 6:30 am and 7:00 pm, during weekdays. However, 58% of people thought that they had enough exposure to sunlight. The majority had heard of vitamin D, but knowledge about the role and sources of vitamin D was low. Among those who knew that sunlight was a source of vitamin D, the majority spent less than 1 h in the sun in the past week (76.4% vs 23.6%, < 1 h in the sun in the past week vs > 1 h in the sun in the past week, chi-square p < 0.05). There were significantly more users of sunscreen products (75.5% vs 53.0%, p < 0.0001, sunscreen users vs non-users) and parasols (68.4% vs 43.7%, p < 0.0001, parasol users vs non-users) among respondents who knew that vitamin D was good for bone health and that sunlight was a source of vitamin D. Age, occupation, subjects who liked going in the sun were factors associated with awareness of vitamin D but age was the only predictive factor for giving correct answers to the actions and sources of vitamin D.
The survey revealed considerable ignorance and confusion about the role of sunlight in vitamin D production, and the function and sources of vitamin D. Attitudes and behaviour toward sunlight were largely negative and many took measures to avoid sunlight, particularly among younger (middle-aged) women who had good awareness of vitamin D.
PMCID: PMC1584409  PMID: 16956420
6.  Vitamin D supply: from sun or pill? - Attitudes and recommendation on vitamin D and impact on sun protection practices among German general practitioners evaluated by the network of dermato-oncologists, Onkoderm e.V. 
Oncology Letters  2012;4(6):1392-1396.
Recommendations concerning the intake of vitamin D and/or sunlight exposure in the handling of patients with vitamin D deficiency remain a matter of debate. The present study of the German network of dermato-oncologists (Onkoderm e.V.) refers to an inquiry conducted among general practitioners on this and related issues. Based on 448 answers provided to 10 distinct questions, the consulted physicians recommended vitamin D intake (94% replies) and/or exposure to sunlight (63% replies) in their patients with vitamin D deficiency. An average of approximately 26 min daily unprotected exposure to sunlight at midday in spring and summer was recommended. Nevertheless, 91% of the physicians considered the use of creams protecting against sunlight to be judicious. However, only 54% of physicians considered it worthwhile practice to protect oneself intensively against UV radiation. This study indicates evidence of a reduction in sun protection practices. Yet, approximately 25% of the patients were considered to present vitamin D deficiency and, hence, recommendations to prevent or correct the latter situation should not be ignored. Nevertheless, we consider that there is a need to focus messages regarding sun exposure and for continued sun protection practices. These messages should specifically focus on the vitamin D issue to ensure that the incidence of skin cancer does not increase.
PMCID: PMC3506811  PMID: 23226810
vitamin D; sunlight exposure; skin cancer
7.  The High Prevalence of Vitamin D Insufficiency across Australian Populations Is Only Partly Explained by Season and Latitude 
Environmental Health Perspectives  2007;115(8):1132-1139.
Inadequate sun exposure and dietary vitamin D intake can result in vitamin D insufficiency. However, limited data are available on actual vitamin D status and predictors in healthy individuals in different regions and by season.
We compared vitamin D status [25-hydroxyvitamin D; 25(OH)D] in people < 60 years of age using data from cross-sectional studies of three regions across Australia: southeast Queensland (27°S; 167 females and 211 males), Geelong region (38°S; 561 females), and Tasmania (43°S; 432 females and 298 males).
The prevalence of vitamin D insufficiency (≤ 50 nmol/L) in women in winter/spring was 40.5% in southeast Queensland, 37.4% in the Geelong region, and 67.3% in Tasmania. Season, simulated maximum daily duration of vitamin D synthesis, and vitamin D effective daily dose each explained around 14% of the variation in 25(OH)D. Although latitude explained only 3.9% of the variation, a decrease in average 25(OH)D of 1.0 (95% confidence interval, 0.7–1.3) nmol/L for every degree increase in latitude may be clinically relevant. In some months, we found a high insufficiency or even deficiency when sun exposure protection would be recommended on the basis of the simulated ultraviolet index.
Vitamin D insufficiency is common over a wide latitude range in Australia. Season appears to be more important than latitude, but both accounted for less than one-fifth of the variation in serum 25(OH)D levels, highlighting the importance of behavioral factors. Current sun exposure guidelines do not seem to fully prevent vitamin D insufficiency, and consideration should be given to their modification or to pursuing other means to achieve vitamin D adequacy.
PMCID: PMC1940076  PMID: 17687438
25(OH)D; behavior; latitude; UV index; UVR; vitamin D; vitamin D index
8.  Vitamin D Beliefs and Associations with Sunburns, Sun Exposure, and Sun Protection 
The main objective of this study was to examine certain beliefs about vitamin D and associations with sun exposure, sun protection behaviors, and sunburns. A total of 3,922 lifeguards, pool managers, and parents completed a survey in 2006 about beliefs regarding vitamin D and sun-related behaviors. Multivariate ordinal regression analyses and linear regression analysis were used to examine associations of beliefs and other variables. Results revealed that Non-Caucasian lifeguards and pool managers were less likely to agree that they needed to go out in the sun to get enough vitamin D. Lifeguards and parents who were non-Caucasian were less likely to report that sunlight helped the body to produce vitamin D. A stronger belief about the need to go out in the sun to get enough vitamin D predicted more sun exposure for lifeguards. For parents, a stronger belief that they can get enough vitamin D from foods predicted greater sun protection and a stronger belief that sunlight helps the body produce vitamin D predicted lower sun exposure. This study provides information regarding vitamin D beliefs and their association with certain sun related behaviors across different demographic groups that can inform education efforts about vitamin D and sun protection.
PMCID: PMC3407911  PMID: 22851950
sun exposure habits; vitamin D knowledge; sunscreen use; sun protection behavior
9.  The ABC of Vitamin D: A Qualitative Study of the Knowledge and Attitudes Regarding Vitamin D Deficiency amongst Selected Population Groups 
Nutrients  2013;5(3):915-927.
Objective: In Australia, vitamin D supply in food is limited, and sun exposure is the main source of vitamin D. However skin cancer risk is high, and the need to gain some sun exposure for adequate vitamin D is challenging public health messages to use protection in the sun. The complex vitamin D public health message may be confusing the public and, in particular, those at highest risk for vitamin D deficiency. This study explored vitamin D and sun exposure attitudes, knowledge and practices of some groups considered at risk of vitamin D deficiency and those delivering healthy sun exposure messages to children. Method: 52 adults participated in six focus groups. Results: Results corroborated with previous research showing low levels of vitamin D knowledge. Individual and environmental barriers to receiving adequate sun exposure were also identified. Conclusions and Implications: The message advocating balanced sun exposure to produce adequate vitamin D needs to be made clearer and be more effectively communicated. Findings provide insights to aid development of appropriate public health messages for safe sun exposure and vitamin D, especially for vulnerable groups.
PMCID: PMC3705326  PMID: 23503169
vitamin D; focus groups; knowledge and attitudes
10.  Cutaneous vitamin D synthesis versus skin cancer development 
Dermato-endocrinology  2009;1(5):253-261.
In scientific and public communities, there is an ongoing discussion how to balance between positive and negative effects of solar UV-exposure. On the one hand, solar UV-radiation represents the most important environmental risk factor for the development of non-melanoma skin cancer. Consequently, UV protection is an important measure to prevent these malignancies, especially in risk groups. Otherwise, approximately 90% of all vitamin D needed by the human body has to be formed in the skin through the action of UV-radiation. This dilemma represents a serious problem, for an association of vitamin D-deficiency and multiple independent diseases including various types of cancer, bone diseases, autoimmune diseases, infectious diseases, cardiovascular diseases and hypertension has now been reported in a large number of investigative and epidemiologic studies. As a consequence, it has been assumed that for the general population in the US, Europe and other countries, the net effects of solar UV B-radiation on human health are beneficial at or near current levels. We and others have shown that strict sun protection causes vitamin D-deficiency/insufficiency and that detection and treatment of vitamin D-deficiency in sun deprived risk groups is of high importance. Although further work is necessary to define an adequate vitamin D-status and adequate guidelines for solar and artificial UV-exposure, it is at present mandatory that public health campaigns and sun protection recommendations to prevent skin cancer consider these facts. In this review, we analyze the present literature to help developing well-balanced recommendations on sun protection that ensure an adequate vitamin D-status. These recommendations will hopefully protect us against adverse effects of UV protection without significantly increasing the risk to develop UV-induced skin cancer.
PMCID: PMC2836430  PMID: 20808512
vitamin D; solar UV radiation; cancer
11.  Sun-Seeking Behavior to Increase Cutaneous Vitamin D Synthesis: When Prevention Messages Conflict 
Public Health Reports  2011;126(4):533-539.
The public has long been encouraged to engage in sun-safe practices to minimize exposure to sunlight, the major cause of nonmelanoma skin cancer. More recently, some have advocated unprotected sun exposure to increase cutaneous synthesis of vitamin D as a way to promote health. We assessed the net result of these conflicting messages.
In a cross-sectional survey in 2007, questionnaires were mailed to participants of an ongoing cohort study in Washington County, Maryland. The study population consisted of 8,027 adults (55% response rate).
Thirty percent of respondents were aware that unprotected sun exposure increased endogenous vitamin D levels. Among those who were aware of this benefit, 42% reported going out into the sun to increase vitamin D levels. Sun-seeking to increase vitamin D production did not significantly differ according to self-reported personal history of skin cancer, but was significantly higher among women, older age groups, those with less education, and vitamin D supplement users.
A substantial proportion of respondents reported sun-seeking behavior expressly to increase endogenous vitamin D levels. The message about sun exposure and vitamin D is reaching the general public; however, this finding poses challenges to skin cancer prevention efforts.
PMCID: PMC3115212  PMID: 21800747
12.  A randomised controlled trial of a theory-based intervention to improve sun protective behaviour in adolescents ('you can still be HOT in the shade'): study protocol 
BMC Cancer  2012;12:1.
Most skin cancers are preventable by encouraging consistent use of sun protective behaviour. In Australia, adolescents have high levels of knowledge and awareness of the risks of skin cancer but exhibit significantly lower sun protection behaviours than adults. There is limited research aimed at understanding why people do or do not engage in sun protective behaviour, and an associated absence of theory-based interventions to improve sun safe behaviour. This paper presents the study protocol for a school-based intervention which aims to improve the sun safe behaviour of adolescents.
Approximately 400 adolescents (aged 12-17 years) will be recruited through Queensland, Australia public and private schools and randomized to the intervention (n = 200) or 'wait-list' control group (n = 200). The intervention focuses on encouraging supportive sun protective attitudes and beliefs, fostering perceptions of normative support for sun protection behaviour, and increasing perceptions of control/self-efficacy over using sun protection. It will be delivered during three × one hour sessions over a three week period from a trained facilitator during class time. Data will be collected one week pre-intervention (Time 1), and at one week (Time 2) and four weeks (Time 3) post-intervention. Primary outcomes are intentions to sun protect and sun protection behaviour. Secondary outcomes include attitudes toward performing sun protective behaviours (i.e., attitudes), perceptions of normative support to sun protect (i.e., subjective norms, group norms, and image norms), and perceived control over performing sun protective behaviours (i.e., perceived behavioural control).
The study will provide valuable information about the effectiveness of the intervention in improving the sun protective behaviour of adolescents.
PMCID: PMC3267687  PMID: 22212211
Oncology; Skin cancer; Adolescent; School; Intervention; Theory of planned; Behaviour; Education; Sun protective behaviour
13.  Vitamin D deficiency in cord plasma from multiethnic subjects living in the tropics 
Vitamin D deficiency is commonly reported in high latitude areas and in dark pigmented individuals. However, nothing is known about vitamin D in cord blood from multiethnic subjects living in the tropics.
Our study objective was to determine the prevalence of vitamin D deficiency in summer and winter in cord blood from multiethnic individuals in Hawai'i where sufficient sun irradiance occurs year-round for cutaneous vitamin D production.
25-hydroxyvitamin D (25(OH)D) levels were quantified by enzyme-immunoassay in 100 cord plasma samples from apparently healthy full term newborns and their mothers. Stratification was performed by birth season and ethnicity.
Mean 25(OH)D levels were 24.5 ng/mL (9.1-68.3 ng/mL). Overall, 28% of samples were Vitamin D deficient (<20 ng/mL) and 50% were insufficient (20-30 ng/mL). 25(OH)D levels (ng/mL) were highest in Caucasians (30.5, n=19) then Asians (25.1, n=43), Hispanics (21.5, n=3), Pacific Islanders (20.0, n=25), and African Americans (19.6, n=2). Differences among groups were significant (p=0.008). Cord plasmas from summer versus winter were higher overall (p=0.001) and among Asians (p=0.0003). Seasonal changes were correlated with sun irradiance overall (r=0.43, p=0.0001), among Caucasians (r=0.45, p=0.05), and among Asians (r=0.45, p=0.0001).
Our results suggest that prenatal supplement recommendations of 400 IU vitamin D/day does not protect against vitamin D deficiency, even in subjects living in the tropics where ample sun irradiance exists for cutaneous vitamin D synthesis. The high prevalence of vitamin D deficiency we observed emphasizes the necessity for regular 25(OH)D monitoring, particularly during pregnancy and lactation, in dark pigmented individuals, and during winter months.
PMCID: PMC3983239  PMID: 24024766
vitamin D insufficiency; seasonal variation; cord blood; Hawaii
14.  Relationship between sun exposure and melanoma risk for tumours in different body sites in a large case-control study in a temperate climate 
A melanoma case-control study was conducted to elucidate the complex relationship between sun exposure and risk.
960 population-ascertained cases, 513 population and 174 sibling controls recruited in England provided detailed sun exposure and phenotype data; a subset provided serum 25-hydroxyvitamin D3 levels.
Phenotypes associated with a tendency to sunburn and reported sunburn at ≥20 years of age were associated with increased melanoma risk (OR 1.56, 95% CI 1.23-1.99). Holiday sun exposure was not associated with an increased melanoma risk although this may be in part because reported sun exposure overall was much lower in those with a sun-sensitive phenotype, particularly among controls. Head and neck melanoma was associated with less sun exposure on holidays at low latitudes (OR 0.39, 95% CI (0.23-0.68) for > 13 hours /year compared to <3.1). Overall the clearest relationship between reported sun exposure and risk was for average weekend sun exposure in warmer months, which was protective (OR 0.67, 95% CI 0.50-0.89 for highest versus lowest tertile of exposure). Serum vitamin D levels were strongly associated with increased weekend and holiday sun exposure.
Sun-sensitive phenotypes and reported sunburn were associated with an increased risk of melanoma. Although no evidence was seen of a causal relationship between holiday sun exposure and increased risk, this is consistent with the view that intense sun exposure is causal for melanoma in those prone to sunburn. A protective effect of regular weekend sun exposure was seen, particularly for limb tumours, which could be mediated by photoadaption or higher vitamin D levels.
PMCID: PMC3046902  PMID: 21084183
15.  Skin pigmentation, sun exposure and vitamin D levels in children of the Avon Longitudinal Study of Parents and Children 
BMC Public Health  2014;14:597.
It has been hypothesised that light skin pigmentation has arisen to ensure adequate levels of vitamin D as human populations moved out of Africa and into higher latitudes. Vitamin D, which is primarily obtained through exposure to sunlight (specifically ultraviolet radiation B (UVR-B)), has been inversely associated with several complex diseases. Greater sun exposure, on the other hand, is a well-known cause of skin cancer. The potential of UVR to be beneficial for some health outcomes but detrimental for others has prompted a public health debate on how to balance the positive and negative consequences of sun exposure. In this study we aimed to determine the validity of the evolutionary hypothesis linking lighter skin with higher vitamin D concentrations in a European population. Additionally, we aimed to examine the influence of pigmentation on personal behaviour towards sunlight exposure and the effects of this behaviour on vitamin D.
We combined genetic variants strongly associated with skin colour, tanning or freckling to create genetic scores for each of these phenotypes. We examined the association of the scores with pigmentary traits, sun exposure and serum 25-hydroxyvitamin D (25(OH)D) levels among children of the Avon Longitudinal Study of Parents and Children (ALSPAC, N = 661 to 5649).
We found that fairer-skinned children, i.e. those with higher pigmentation score values, had higher levels of 25(OH)D (0.6 nmol/l; 95% CI 0.2, 1.0; per unit increase in skin colour score; N = 5649). These children also used more protection against the damaging effects of UVR.
In this population taking protective measures against sunburn and skin cancer does not seem to remove the positive effect that having a less pigmented skin has on vitamin D production. Our findings require further replication as skin pigmentation showed only a small effect on circulating 25(OH)D.
PMCID: PMC4067096  PMID: 24924479
Pigmentation; Sun exposure; Vitamin D; ALSPAC; Genetic scores
16.  Prevalence of vitamin D deficiency during the summer and its relationship with sun exposure and skin phototype in elderly men living in the tropics 
The aim of the study reported here was to determine the prevalence of vitamin D deficiency among elderly men and its association with sun exposure and skin phototypes.
Subjects and methods
This was an analytical cross-sectional study, which involved 284 men aged 60 years or over, randomly recruited from a basic care unit in the city of Recife (Brazil).
Serum levels of 25 hydroxyvitamin D (25(OH)D), sun index, and skin phototypes were evaluated.
The prevalence of vitamin D deficiency was 31.5% and 66.7% when cut points of less than 20 and 30 ng/mL, respectively, were used. Mean serum 25(OH)D was 27.86 ± 13.52 standard deviation (SD) ng/mL. There was no difference (P = 0.113) in 25(OH) D (23.98 ± 14.66 SD vs 29.88 ± 13.78 SD) between individuals in the lowest quartile (Q) of the sun index (Q1: 1.96) compared with those in the highest (Q4: 7.86). When considering a cutoff of 20 ng/mL, the sun index was different in the two groups (P = 0.006), but there was no difference when cutoffs of 25 and 30 ng/mL were used. After adjustment, sun index and body mass index were associated positively and negatively, respectively with serum 25(OH)D independently. Most subjects (66.7%) had Fitzpatrick’s skin phototypes IV, V, and VI. Low calcium intake was observed in 72%. There was no difference in serum 25(OH)D levels between patients with low intake and those with intermediate and high intakes. Only 2.5% were taking a vitamin supplement.
We found a high prevalence of vitamin D deficiency among elderly men despite their high sun exposure during the summer months.
PMCID: PMC3794891  PMID: 24124357
sun index; serum 25(OH)D levels; body mass index; Brazil
17.  Vitamin D deficiency and sun avoidance among university students at Abu Dhabi, United Arab Emirates 
Dermato-endocrinology  2011;3(4):235-239.
This study offers evidence that vitamin D deficiency could be a major public health burden among young Emirati adults, mostly because of sun deprivation in a sun-blessed country. This study included a random sample of 138 females and 70 males tested for serum 25-hydroxyvitamin D [25(OH)D] status. To further evaluate the predictors of vitamin D status in this population, the study examined diet, obesity and sun exposure. In summer, the mean serum 25(OH)D concentration for females was 20.9 ± 14.9 nmol/L, whereas that for males was 27.3 ± 15.7 nmol/L. Females scored significantly higher than males on the sun avoidance inventory (SAI), indicating that females avoid sun exposure to a greater extent than males, possibly explaining the lower vitamin D status. A significant negative correlation also existed between SAI and vitamin D status (Pearson's r = −0.33; p < 0.01), but no significant association was evident between vitamin D status and body mass index (Pearson's r = 0.03; p = 0.33) or low dietary intake of vitamin D-fortified foods (Pearson's r = 0.08; p = 0.13). The mean serum 25(OH)D concentration for females tested in winter was 31.3 ± 12.3 nmol/L while in the summer, it was 20.9 ± 14.9 nmol/L. This difference was statistically significant, suggesting that seasonal variation plays an important role in vitamin D status in the United Arab Emirates. Fortification of foods and drinks with vitamin D, supplementation and sensible sun exposure are important steps toward minimizing vitamin D deficiency.
PMCID: PMC3256339  PMID: 22259650
vitamin D deficiency; 25(OH)D; young adult emiratis; females; United Arab Emirates; sun avoidance inventory; high performance liquid chromatography; food frequency questionnaire
18.  Factors Associated With Risky Sun Exposure Behaviors Among Operating Engineers 
The objective of this study was to determine the factors associated with sun exposure behaviors among Operating Engineers (heavy equipment operators).
Operating Engineers (N=498) were asked to complete a cross-sectional survey. Linear and logistic regression analyses were used to determine health behavior, perceptional, and demographic factors associated with sun exposure behavior (sun burns, blistering, use of sunscreen, and interest in sun protection services).
Almost half reported 2 or more sunburns/summer and the median times blistering was 2 with a range of 0–100. About one-third never used sun block while just over one-third rarely used sun block. Almost one-quarter were interested in sun protection guidance. Multivariate analyses showed that perceptions of skin type, alcohol problems, fruit intake, BMI, sleep quality, age, sex, and race were significantly associated with at least one of the outcome variables (p<.05).
Operating Engineers are at high risk for skin cancer due to high rates of exposure to UV light and low rates of sun block. Subgroups of Operating Engineers are particularly at risk for sun damage. Interventions are needed to decrease sun exposure among Operating Engineers.
PMCID: PMC3435434  PMID: 22692974
Sun exposure; Sunburn; Sunscreens; Sun protection; Worksite interventions
19.  Pigmentation and Vitamin D Metabolism in Caucasians: Low Vitamin D Serum Levels in Fair Skin Types in the UK 
PLoS ONE  2009;4(8):e6477.
Vitamin D may play a protective role in many diseases. Public health messages are advocating sun avoidance to reduce skin cancer risk but the potential deleterious effects of these recommendations for vitamin D metabolism have been poorly investigated.
Methodology/Principal Findings
We investigated the association between 25-hydroxy-vitamin D (25(OH)D), skin type and ultraviolet exposure in 1414 Caucasian females in the UK. Mean age of the cohort was 47 years (18–79) and mean 25(OH)D levels were 77 nmol/L (6–289). 25(OH)D levels were strongly associated with season of sampling with higher levels in the spring and summer months (p<0.0001). Light skin types (skin type 1 and 2) have lower levels of 25(OH)D (mean 71 nmol/L) compared to darker skin types (skin type 3 and 4) (mean 82 nmol/L) after adjusting for multiple confounders (p<0.0001). The trend for increasing risk of low vitamin D with fairer skin types was highly significant despite adjustment for all confounders (p = 0.001).
Contrary to previous studies across different ethnic backgrounds, this study within Caucasian UK females shows that fair skin types have lower levels of 25(OH)D compared to darker skin types with potential detrimental health effects. Public health campaigns advocating sun avoidance in fair skinned individuals may need to be revised in view of their risk of vitamin D deficiency.
PMCID: PMC2714459  PMID: 19649299
20.  Feasibility of a GP delivered skin cancer prevention intervention in Australia 
BMC Family Practice  2014;15:137.
Despite years of public education, sun-related behaviours are difficult to change and a recent survey showed low levels of sun protection. In this study we evaluated the feasibility and acceptability of an opportunistic skin cancer prevention intervention in general practice.
We used a controlled pre-and-post intervention design. Participants (n = 100) were recruited sequentially from patients attending two general practices in Sydney, Australia, from November to December 2010. Participants in the intervention practice (n = 50) received general practitioner delivered sun protection advice after completing a skin cancer risk assessment tool, and a sun protection pamphlet, in addition to routine care, at a single attendance. The skin cancer risk assessment tool provided three levels of risk. The general practitioner (GP) reinforced the level of risk and discussed sun protection. Participants in the control practice (n = 50) received routine care. We measured feasibility by patients’ and GPs’ participation in the intervention and time taken, and acceptability by intervention participants and GPs ratings of the intervention. We measured reported sun-related knowledge, attitudes and behaviour between the two groups at 1 and 13 months.
The intervention was found to be feasible within existing primary care team arrangements. Participation at baseline was 81% (108/134), and repeated participation was 88% (88/100) at 1 month and 70% (70/100) at 13 months. Participants and practitioners found the intervention acceptable. At 1 month, sun-related knowledge had increased in both patient groups, with a greater increase in the intervention group (adjusted mean difference 0.48, p = 0.034). There were no differences between groups in sun-related knowledge, attitudes and behaviour at 13 months.
A brief opportunistic skin cancer prevention intervention in general practice is feasible and acceptable. Further research in this setting with a more intensive intervention would be justified.
PMCID: PMC4128422  PMID: 25070692
Feasibility studies; Skin neoplasms; Preventive medicine; General practice; Health behaviour
21.  Vitamin D and melanoma 
Dermato-endocrinology  2013;5(1):121-129.
Recreational sun exposure and sunburn are causal for melanoma but the risk is strongly genetically determined. Health promotion advice about sun protection should be aimed at susceptible individuals (pale skin, freckles, large numbers of melanocytic nevi and a family history). We discuss here the evidence that sun-sensitive people have lower vitamin D levels and that, in practice, it is very difficult for such individuals to achieve sufficient levels without supplementation in the UK at least. We conclude that melanoma susceptible sun-avoidant individuals should be advised to avoid insufficiency by supplementation.
Vitamin D is anti-proliferative in vitro for some melanoma cell lines. In a large melanoma cohort we have observed that lower serum 25-hydroxyvitamin D2/D3 levels at diagnosis were associated with thicker tumors and poorer prognosis (study as yet not validated). In the UK, melanoma patients commonly have sub-optimal 25-hydroxyvitamin D2/D3 levels at and post diagnosis; we discuss approaches to management of such patients based on some new data from our group.
PMCID: PMC3897580  PMID: 24494045
supplementation; vitamin D serum levels; risk; 25-hydroxyvitamin D2/D3 levels; survival; prevention
22.  Sensitivity to change of the Beach Questionnaire to behaviour, attitudes and knowledge related to sun exposure: quasi-experimental before-after study 
BMC Public Health  2015;15:60.
Health questionnaires must present accredited measurement properties such as validity, reliability and sensitivity to change, the latter being essential for interventions to be planned and for evaluating their effectiveness. The aim of this study was to evaluate the sensitivity to change of a Beach Questionnaire.
Quasi-experimental before-after study carried out in 2011, for a study population of adolescents attending schools in the Costa del Sol. First, the questionnaire was administered to the adolescents, after which a multicomponent educational intervention was carried out; finally, three months later, the same questionnaire was re-administered to the same adolescents. Changes were assessed in the categories of each item, using the McNemar test, and the changes in the scores, standardised to a range of 0–100, using the Student t test for paired samples, and including the mean of the differences and the 95% confidence interval. The level of statistical significance was set at p < 0.05.
228 adolescents, aged 14–17 years, and 55.3% were girls. Statistically significant changes were observed in sunburn experiences, exposure to the sun at mid-day and attitudes to sun exposure and suncreams. For the seven items related to knowledge about sun exposure, a higher rate of correct answers was observed. The analysis of changes, within the standardised range, revealed a significant improvement in the scores for sun exposure habits (MD 4.33; CI 95% 2.2-6.5), attitudes to sun exposure (MD 2.22; CI 95% 1.2-3.2) and knowledge (MD 9.10; CI 95% 7.1-11.1), but not in those for sun-protection practices (MD 0.23; CI 95% -1.2-1.7).
The Beach Questionnaire on behaviour, attitudes and knowledge related to sun exposure is the first such instrument in Spanish language to provide sufficient sensitivity to change. It constitutes a useful tool for epidemiologic research into photoprotection and for skin cancer prevention programmes.
PMCID: PMC4314809  PMID: 25636540
Health questionnaire; Validation; Sensitivity to change; Sun exposure habits; Attitudes to sun; Knowledge about sun exposure
23.  Fundamental questions to sun protection 
Dermato-endocrinology  2010;2(1):19-25.
Since exposure to sunlight is a main factor in the development of non-melanoma skin cancer and there are associations between malignant melanoma and short-term intense ultraviolet (UV) exposure, particularly burning in childhood, strict protection from UV-radiation is recommended. However, up to 90% of all requisite vitamin D has to be formed within the skin through the action of the sun—a serious problem, for a connection between vitamin D deficiency, demonstrated in epidemiological studies, and various types of cancer and other diseases has been confirmed. A UVB-triggered skin autonomous vitamin D3 synthesis pathway has recently been described, producing the active Vitamin D metabolite calcitriol. This cutaneous vitamin D3 pathway is unique. Keratinocytes and dendritic cells can convert vitamin D to calcitriol. Cutaneous T cells activated in the presence of calcitriol express the chemokine receptor CCR10 attracting them to the chemokine CCL27 that keratinocytes express selectively in the epidermis, and migrate from dermal layers of the skin to the epidermis under UV radiation. Thus, calcitriol has endocrine roles beyond its calciotropic action, including cell growth and cancer prevention. Therefore, strict sun protection procedures to prevent skin cancer may induce the risk of vitamin D deficiency. As there is evidence that the protective effect of less intense solar radiation can outweigh its mutagenic effect, better balanced approaches to sun protection should be sought.
PMCID: PMC3084961  PMID: 21547144
vitamin D; vitamin D synthesis (skin); immune system (skin); sun protection; ultraviolet radiation; photo therapy; cancer
24.  Parents' knowledge and behaviour concerning sunning their babies; a cross-sectional, descriptive study 
BMC Pediatrics  2006;6:27.
For centuries, sunlight has been used for therapeutic purposes. Parents still sun their infants to treat neonatal jaundice, nappy rash or mostly to supply vitamin D for bone development as a consequence of health beliefs. In this study we aimed to assess knowledge and behaviour of parents about benefits of sunlight and sun protection.
In this study, parents attending to governmental primary healthcare units for their children's routine vaccinations, upon their informed consent, were consecutively enrolled during one month. Data were collected by a semi-structured questionnaire.
The mean age of 118 enrolled parents and their babies were 27.9 ± 6.5 years and 8.3 ± 5.8 months, respectively. Most of the participants were mothers (93.2%), housewives (81.4%) with an educational level of ≥6 years (71.2%). Sunlight was considered beneficial for bone development (86.4%), diaper rash (5.9%) and neonatal jaundice (12.7%). In case of neonatal jaundice 72.0% of the participants reported that they would consult a physician. Most of the participants (82.2%) were sunning their babies outdoors. Nearly half (49.7%) of them got this information from medical staff. Fifty two percent of the parents were sunning their babies before 10–11 a.m. and/or after 3 p.m. Only 13.6% of parents reported using sunscreen for their babies, and the majority of them were using sun protecting factor ≥ 15. One forth of the sunscreen users was using sunscreen according to their physicians' advice.
Most of the participants were aware of the benefits of sunlight; especially for bone development. However they were displaying inappropriate behaviour while sunning their babies for health reasons. More education should be given to parents about the danger of sunlight at primary health care units while advising to sun their babies, if any.
PMCID: PMC1634747  PMID: 17076884
25.  Evidence-based D-bate on health benefits of vitamin D revisited 
Dermato-endocrinology  2012;4(2):183-190.
Vitamin D has received worldwide attention not only for its importance for bone health in children and adults but also for reducing risk for many chronic diseases including autoimmune diseases, type 2 diabetes, heart disease, many cancers and infectious diseases. Vitamin D deficiency is pandemic due to the fact that most humans have depended on sun for their vitamin D requirement which they now either avoid or wear sun protection for fear of skin cancer. There are few foods that naturally contain vitamin D. Some countries permit vitamin D fortification especially dairy products, some cereals and juice products. The Institute of Medicine made its recommendations based on a population-based model; the Endocrine Society's Practice Guidelines on Vitamin D was for the prevention and treatment of vitamin D deficiency, which helps explain the differences in the recommendations. The Guidelines defined vitamin D deficiency as a 25-hydroxyvitamin D < 20 ng/mL, insufficiency as 21–29 ng/mL and sufficiency as 30–100 ng/mL. To prevent vitamin D deficiency The Guidelines recommended vitamin D intake should be: children < 1 y 400–1,000 IU/d, children 1–18 y 600–1,000 IU/d and adults 1,500–2,000 IU/d.
PMCID: PMC3427198  PMID: 22928075
vitamin D; 25-hydroxyvitamin D; sunlight; Institute of Medicine; Endocrine Society Practice Guidelines

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