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1.  Test-Retest Reliability of the WHI Physical Activity Questionnaire 
Few physical activity (PA) questionnaires were designed to measure the lifestyles and activities of women. We sought to examine the test-retest reliability of a PA questionnaire used in the Women's Health Initiative (WHI) Study. Differences in reliability were also explored by important covariates.
Participants (n=1092) were post-menopausal women aged 50-79 years, randomly selected from the baseline sample of participants in the WHI Observational Study. The WHI physical activity questionnaire collects usual frequency, duration, and pace of recreational walking, frequency and duration of other recreational activities or exercises (mild, moderate and strenuous), household, and yard activities. Approximately half of the women (n=569) repeated questions on recreational PA, the other half (n=523) repeated questions related to household and yard activities (mean 3 months apart). Test-retest reliability was assessed with kappa and intraclass correlation coefficients (ICC1,1).
Overall, questions on recreational walking, moderate recreational PA, and strenuous recreational PA had higher test-retest reliability (weighted kappa range 0.50-0.60), than questions on mild recreational PA (weighted kappa range 0.35-0.50). The ICC1,1 for moderate to strenuous recreational PA was 0.77 (95% CI 0.73, 0.80) and total recreational PA was 0.76 (95% CI 0.71, 0.79). Substantial reliability was observed for the summary measures of yard activities (ICC1,1 0.71; 95% CI 0.66, 0.75) and household activities (ICC1,1 0.60, 95% CI 0.55, 0.66). No meaningful differences were observed by race/ethnicity, age, time between test and retest, and amount of reported PA.
The WHI PA questionnaire demonstrated moderate to substantial test-retest reliability in a diverse sample of post-menopausal women.
PMCID: PMC2692735  PMID: 19204598
Epidemiology; movement; reproducibility; women's health; exercise
2.  Frequency of Leisure-Time Physical Activity and Serum 25-Hydroxyvitamin D Levels in the US Population: Results from the Third National Health and Nutrition Examination Survey 
American Journal of Epidemiology  2008;168(6):577-586.
The decline in vitamin D status among older people is probably due to decreased synthesis of vitamin D by sun-exposed skin and/or decreased outdoor activity. The authors examined the association between outdoor leisure physical activity and serum 25-hydroxyvitamin D in the Third National Health and Nutrition Examination Survey (1988–1994) (n = 15,148 aged ≥20 years). The mean 25-hydroxyvitamin D concentration declined with increasing age, with 79, 73, and 68 nmol/liter for persons aged 20–39, 40–59, and 60 or more years. The proportion that engaged in outdoor activity in the past month was 80% for persons aged 20–39 and 40–59 years but 71% for those aged 60 or more years. In contrast, the mean difference in 25-hydroxyvitamin D between those who participated in outdoor activities daily compared with those who did not participate in the past month was similar for the youngest and oldest age groups: 13 and 16 nmol/liter, respectively. Those persons aged 60 or more years who participated in daily outdoor activities had a mean 25-hydroxyvitamin D concentration similar to that of persons aged 20–39 years: 77 versus 79 nmol/liter, respectively. These nationally representative data suggest that persons aged 60 or more years can synthesize enough vitamin D from daily outdoor activities to maintain vitamin D levels similar to those of young adults.
PMCID: PMC2727193  PMID: 18579538
aged; ethnic groups; exercise; vitamin D
3.  A Fitness Performance Test for School Children and its Correlation with Physical Working Capacity and Maximal Oxygen Uptake 
Canadian Medical Association Journal  1967;96(18):1262-1269.
The Canadian Association for Health, Physical Education and Recreation fitness test (CAHPER test) composed of six items was compared to two laboratory tests of endurance fitness, physical working capacity at a minute pulse rate of 170 (PWC170) and maximum oxygen uptake (Vo2 max.) in over 500 Winnipeg school children of both sexes aged 6 to 17 years. CAHPER test results were similar to the national average published by CAHPER in a test booklet. Correlation coefficients (r) of Vo2 max. for boys with the CAHPER tests were: sit-ups .42, broad jump .69, shuttle run .50, arm hang .43, 50-yard dash .60, 300-yard run .65; for girls the r values were about half the values for the boys. Much of the correlation between CAHPER tests and Vo2 max. or PWC170 depended on the association of each test with body size. When multiple correlations were obtained including surface area as the first variable, the only significant factor correlating with the endurance tests was the arm hang; none of the other tests showed a significant correlation. “Physical fitness” is task-specific, so that a subject's position in the scoring scale of a fitness test depends entirely upon the test. The CAHPER test for physical fitness shows little or no correlation with standard laboratory measures of endurance in average children.
PMCID: PMC1922875  PMID: 6022304
4.  Physical Activity During Pregnancy and Risk of Hyperglycemia 
Journal of Women's Health  2012;21(7):769-775.
To determine the association between moderate and vigorous physical activities (MVPA) during midpregnancy and the risk of hyperglycemia.
Data were from 1437 pregnant women. Frequency, duration, and intensity of MVPA during the previous 7 days were collected via questionnaire at 17–22 weeks' gestation. Modes of MVPA included work, recreation, transportation, caregiving, and indoor and outdoor household activities. Hyperglycemia was defined as a glucose concentration ≥130 mg/dL on a 1-hour, 50-g glucose challenge test or gestational diabetes mellitus (GDM) assessed at ∼27 weeks' gestation. Multivariable Poisson regression estimated risks of hyperglycemia associated with total and mode-specific MVPA.
There were 269 women (18.7%) with hyperglycemia. Any metabolic equivalent (MET) hours/week of recreational MVPA was associated with a 27% lower risk of hyperglycemia (adjusted relative risk, [aRR] 0.73, 95% confidence interval [95%CI] 0.54-0.99). Multiplicative interaction terms were significant for prepregnancy body mass index (BMI) and recreational MVPA (p=0.01). Among women with prepregnancy BMI <25 kg/m2, recreational MVPA was associated with a 48% lower risk of hyperglycemia (aRR 0.52, 95%CI 0.33-0.83) compared to women who reported none. There was no association of hyperglycemia and recreational MVPA among women with prepregnancy BMI <25 kg/m2.
Recreational MVPA during pregnancy is associated with a lower risk of hyperglycemia, specifically among women with prepregnancy BMI <25 kg/m2. Further research is warranted to determine recommended amounts and intensities of physical activity and to discern whether there are differences in the effects of physical activity between specific modes of physical activity or among subgroups of women in relation to hyperglycemia.
PMCID: PMC3387759  PMID: 22537020
5.  Recreational Physical Activity and Steroid Hormone Levels in Postmenopausal Women 
American Journal of Epidemiology  2009;170(9):1095-1104.
Recreational physical activity has been both positively and inversely associated with cancer risk for postmenopausal women, acting presumably through hormonal mechanisms. Relatively little is known about the effects of exercise on postmenopausal steroid hormone levels. The authors evaluated the association between recreational activity and plasma steroid hormones among 623 US healthy, postmenopausal women in the Nurses’ Health Study not using exogenous hormones at the time of blood draw (1989–1990). Participants self-reported recreational physical activity by questionnaire in 1986, 1988, and 1992. Plasma samples were assayed for estrogens, androgens, and sex hormone-binding globulin. Geometric mean hormone levels adjusted and not adjusted for body mass index were calculated. In general, estrogen and androgen levels were lower in the most- and the least-active women compared with those reporting moderate activity, suggesting a U-shaped relation. For example, estrone sulfate levels in quintiles 1–5 of metabolic equivalent task-hours were 197, 209, 222, 214, and 195 pg/mL, respectively. Tests for nonlinearity using polynomial regression were significant for several estrogens, androgens, and sex hormone-binding globulin (2-sided P ≤ 0.01). These results suggest the possibility of a nonlinear relation between recreational physical activity and hormone levels in postmenopausal women.
PMCID: PMC2781741  PMID: 19783585
androgens; biological markers; cohort studies; estrogens; exercise; hormones
6.  Prepregnancy Obesity Predicts Poor Vitamin D Status in Mothers and Their Neonates1,2 
The Journal of nutrition  2007;137(11):2437-2442.
Obesity is a risk factor for vitamin D deficiency, but this relation has not been studied among pregnant women, who must sustain their own vitamin D stores as well as those of their fetuses. Our objective was to assess the effect of prepregnancy BMI on maternal and newborn 25-hydroxyvitamin D [25(OH)D] concentrations. Serum 25(OH)D was measured at 4–21 wk gestation and predelivery in 200 white and 200 black pregnant women and in their neonates’ cord blood. We used multivariable logistic regression models to assess the independent association between BMI and the odds of vitamin D deficiency [25(OH)D <50 nmol/L] after adjustment for race/ethnicity, season, gestational age, multivitamin use, physical activity, and maternal age. Compared with lean women (BMI <25), pregravid obese women (BMI ≥30) had lower adjusted mean serum 25(OH)D concentrations at 4–22 wk (56.5 vs. 62.7 nmol/L; P < 0.05) and a higher prevalence vitamin D deficiency (61 vs. 36%; P < 0.01). Vitamin D status of neonates born to obese mothers was poorer than neonates of lean mothers (adjusted mean, 50.1 vs. 56.3 nmol/L; P < 0.05). There was a dose-response trend between prepregnancy BMI and vitamin D deficiency. An increase in BMI from 22 to 34 was associated with 2-fold (95% CI: 1.2, 3.6) and 2.1-fold (1.2, 3.8) increases in the odds of mid-pregnancy and neonatal vitamin D deficiency, respectively. The rise in maternal obesity highlights that maternal and newborn vitamin D deficiency will continue to be a serious public health problem until steps are taken to identify and treat low 25(OH)D.
PMCID: PMC2556251  PMID: 17951482
7.  The proportion of youths’ physical inactivity attributable to neighbourhood built environment features 
We investigated the independent association between several neighbourhood built environment features and physical inactivity within a national sample of Canadian youth, and estimated the proportion of inactivity within the population that was attributable to these built environment features.
This was a cross-sectional study of 6626 youth aged 11–15 years from 272 schools across Canada. Participants resided within 1 km of their school. Walkability, outdoor play areas (parks, wooded areas, yards at home, cul-de-sacs on roads), recreation facilities, and aesthetics were measured objectively within each school neighbourhood using geographic information systems. Physical inactivity (<5 days/week of 60 minutes of moderate-to-vigorous physical activity) was assessed by questionnaire. Multilevel logistic regression analyses, which controlled for several covariates, examined relationships between built environment features and physical inactivity.
The final regression model indicated that, by comparison to youth living in the least walkable neighbourhoods, the risks for physical inactivity were 28-44% higher for youth living in neighbourhoods in the remaining three walkability quartiles. By comparison to youth living in neighbourhoods with the highest density of cul-de-sacs, risks for physical inactivity were 28-32% higher for youth living in neighbourhoods in the lowest two quartiles. By comparison to youth living in neighbourhoods with the least amount of park space, risks for physical inactivity were 28-37% higher for youth living in the neighbourhoods with a moderate to high (quartiles 2 and 3) park space. Population attributable risk estimates suggested that 23% of physical inactivity within the population was attributable to living in walkable neighbourhoods, 16% was attributable to living in neighbourhoods with a low density of cul-de-sacs, and 15% was attributable to living in neighbourhoods with a moderate to high amount of park space.
Of the neighbourhood built environment exposure variables measured in this study, the three that were the most highly associated with inactivity were walkability, the density of cul-de-sacs, and park space. The association between some of these features and youths’ activity levels were in the opposite direction to what has previously been reported in adults and younger children.
PMCID: PMC3689048  PMID: 23777593
8.  Correlates of Physical Activity at Two Time Points During Pregnancy 
Correlates of prenatal physical activity can inform interventions, but are not well-understood.
Participants in the Pregnancy, Infection, and Nutrition 3 Study were recruited before 20 weeks gestation. Women self-reported frequency, duration, and mode of moderate and vigorous physical activities. We used logistic regression to identify correlates of any physical activity (≥10 minutes/week of any mode), any recreational activity (≥10 minutes/week), and high volume recreational activity (either ≥150 minutes/week of moderate or ≥75 minutes/week of vigorous). Our analysis included 1752 women at 19-weeks gestation and 1722 at 29 weeks.
Higher education, white race, and enjoyment of physical activity were positively correlated with all 3 outcomes. Any recreational activity was negatively associated with parity, body mass index, and history of miscarriage. The associations of history of miscarriage and body mass index differed at 19 weeks compared with 29 weeks. Single marital status, health professional physical activity advice, and time for activity were associated with high volume recreational activity only.
Correlates of physical activity differed by mode and volume of activity and by gestational age. This suggests that researchers planning physical activity interventions should consider the mode and amount of activity and the gestational age of the participants.
PMCID: PMC3749786  PMID: 22454434
leisure activity; gestational age; intervention; barriers; psychosocial
9.  Intensity and Timing in Life of Recreational Physical Activity in Relation to Breast Cancer Risk Among Pre- and Postmenopausal Women 
Regular recreational physical activity has been found to be associated with a decrease in breast cancer risk in women in the majority of epidemiologic studies, but research findings are inconsistent regarding the intensity of activity and timing in life. To address these issues the relations of moderate and vigorous intensity recreational physical activity during ages 14-20, 21-34, 35-50, and over age 50 years to pre- and postmenopausal breast cancer risk were examined. A case-control study of 858 women, with histological confirmation of invasive breast cancer, and 1085 controls, free of any cancer diagnosis, all subjects aged 28-79 years was conducted in the Region of Western Pomerania (Poland). Physical activity was assessed using a self-administered questionnaire with questions on type of activity, duration, frequency, and intensity for each type of activity. Odds ratios (OR) and 95% confidence intervals (CI) of breast cancer associated with physical activity were calculated using unconditional logistic regression. Vigorous physical activity at ages 14-20 and 21-34 years lowered breast cancer risk by at least 35% in premenopausal women and by at least 51% in postmenopausal women for the highest versus lowest quartiles of the activity. The risk was also reduced in postmenopausal women who reported on average more than 1.74 hours per week of vigorous intensity recreational activity in ages >50 years (OR = 0.58; 95%CI = 0.27-0.97; P for trend = 0.013). For moderate activity the relationships remained statistically significant only in postmenopausal women active during ages 14- 20 years. The results indicate also a plausible risk reduction among premeno-pausal women. These results support the hypothesis that recrea-tional activity, particularly done early in life, is associated with a decrease in the invasive breast cancer risk in postmenopausal women. Among premenopausal women, only vigorous forms of activity may significantly decrease the risk.
Key pointsRecreational physical activity of vigorous intensity during ages 14-20 and 21-34 years protect against breast cancer regardless of menopausal status.Vigorous recreational physical activity at ages >50 years was also associated with reduced postmeno-pausal breast cancer risk.The risk reduction was also observed among post-menopausal women engaged in recreational physical activity of moderate intensity at ages 14-20 years.
PMCID: PMC3761722  PMID: 24149701
Exercise; breast cancer; case-control study; prevention
10.  Vitamin D inadequacy in Belgian postmenopausal osteoporotic women 
BMC Public Health  2007;7:64.
Inadequate serum vitamin D [25(OH)D] concentrations are associated with secondary hyperparathyroidism, increased bone turnover and bone loss, which increase fracture risk. The objective of this study is to assess the prevalence of inadequate serum 25(OH)D concentrations in postmenopausal Belgian women. Opinions with regard to the definition of vitamin D deficiency and adequate vitamin D status vary widely and there are no clear international agreements on what constitute adequate concentrations of vitamin D.
Assessment of 25-hydroxyvitamin D [25(OH)D] and parathyroid hormone was performed in 1195 Belgian postmenopausal women aged over 50 years. Main analysis has been performed in the whole study population and according to the previous use of vitamin D and calcium supplements. Four cut-offs of 25(OH)D inadequacy were fixed : < 80 nmol/L, <75 nmol/L, < 50 nmol/L and < 30 nmol/L.
Mean (SD) age of the patients was 76.9 (7.5) years, body mass index was 25.7 (4.5) kg/m2. Concentrations of 25(OH)D were 52.5 (21.4) nmol/L. In the whole study population, the prevalence of 25(OH)D inadequacy was 91.3 %, 87.5 %, 43.1 % and 15.9% when considering cut-offs of 80, 75, 50 and 30 nmol/L, respectively. Women who used vitamin D supplements, alone or combined with calcium supplements, had higher concentrations of 25(OH)D than non-users. Significant inverse correlations were found between age/serum PTH and serum 25(OH)D (r = -0.23/r = -0.31) and also between age/serum PTH and femoral neck BMD (r = -0.29/r = -0.15). There is a significant positive relation between age and PTH (r = 0.16), serum 25(OH)D and femoral neck BMD (r = 0.07). (P < 0.05)
Vitamin D concentrations varied with the season of sampling but did not reach statistical significance (P = 0.09).
This study points out a high prevalence of vitamin D inadequacy in Belgian postmenopausal osteoporotic women, even among subjects receiving vitamin D supplements.
PMCID: PMC1866237  PMID: 17462085
11.  Physical Activity and Survival in Postmenopausal Women with Breast Cancer: Results from the Women’s Health Initiative 
Although studies have shown that physically active breast cancer survivors have lower all-cause mortality, the association between change in physical activity from before to after diagnosis and mortality is not clear. We examined associations among pre- and postdiagnosis physical activity, change in pre- to postdiagnosis physical activity, and all-cause and breast cancer–specific mortality in post-menopausal women. A longitudinal study of 4,643 women diagnosed with invasive breast cancer after entry into the Women’s Health Initiative study of postmenopausal women. Physical activity from recreation and walking was determined at baseline (prediagnosis) and after diagnosis (assessed at the 3 or 6 years post-baseline visit). Women participating in 9 MET-h/wk or more (~3 h/wk of fast walking) of physical activity before diagnosis had a lower all-cause mortality (HR = 0.61; 95% CI, 0.44–0.87; P = 0.01) compared with inactive women in multivariable adjusted analyses. Women participating in ≥9 or more MET-h/wk of physical activity after diagnosis had lower breast cancer mortality (HR = 0.61; 95% CI, 0.35–0.99; P = 0.049) and lower all-cause mortality (HR = 0.54; 95% CI, 0.38–0.79; P < 0.01). Women who increased or maintained physical activity of 9 or more MET-h/wk after diagnosis had lower all-cause mortality (HR = 0.67; 95% CI, 0.46–0.96) even if they were inactive before diagnosis. High levels of physical activity may improve survival in postmenopausal women with breast cancer, even among those reporting low physical activity prior to diagnosis. Women diagnosed with breast cancer should be encouraged to initiate and maintain a program of physical activity.
PMCID: PMC3123895  PMID: 21464032
12.  Vitamin D and Physical Performance in Elderly Subjects: The Pro.V.A Study 
PLoS ONE  2012;7(4):e34950.
The role of Vitamin D in musculoskeletal functionality among elderly people is still controversial. We investigated the association between serum 25-hydroxyvitamin D (25OHD) levels and physical performance in older adults.
2694 community-dwelling elderly women and men from the Progetto Veneto Anziani (Pro.V.A.) were included. Physical performances were assessed by: tandem test, 5 timed chair stands (TCS), gait speed, 6-minute walking (6 mW) distance, handgrip strength, and quadriceps strength. For each test, separate general linear models and loess plots were obtained in both genders, in relation to serum 25OHD concentrations, controlling for several potential confounders.
Linear associations with 25OHD levels were observed for TCS, gait speed, 6 mW test and handgrip strength, but not for tandem test and quadriceps strength. After adjusting for potential confounders, linear associations with 25OHD levels were still evident for the 6 mW distance in both genders (p = .0002 in women; <.0001 in men), for TCS in women (p = .004) and for gait speed (p = .0006) and handgrip strength (p = .03) in men. In loess analyses, performance in TCS in women, in gait speed and handgrip strength in men and in 6 mW in both genders, improved with increasing levels of 25OHD, with most of the improvements occurring for 25OHD levels from 20 to 100 nmol/L.
lower 25OHD levels are associated with a worse coordination and weaker strength (TCS) in women, a slower walking time and a lower upper limb strength in men, and a weaker aerobic capacity (6 mW) in both genders. For optimal physical performances, 25OHD concentrations of 100 nmol/L appear to be more advantageous in elderly men and women, and Vitamin D supplementation should be encouraged to maintain their 25OHD levels as high as this threshold.
PMCID: PMC3335149  PMID: 22539952
13.  Simplified Categorization of Outdoor Activities for Male and Female U.S. Indoor Workers—A Feasibility Study to Improve Assessment of Ultraviolet Radiation Exposures in Epidemiologic Study Questionnaires 
Skin cancer studies depend on questionnaires to estimate exposure to ultraviolet light and subsequent risk but are limited by recall bias. We investigate the feasibility of developing a short checklist of categories comprising outdoor activities that can improve sun exposure questionnaires for use in epidemiologic studies. We recruited 124 working and retired U.S. radiologic technologists (52% women). Each subject was instructed to complete a daily activity diary, listing main indoor and outdoor activities between 9:00 A.M. and 5:00 P.M. during a 7 day period. A total of 4697 entries were associated with 1408 h (21.1%) of the total 6944 h spent outdoors. We were able to classify the activities into seven main activity categories: driving, yard work, home-maintenance, walking or performing errands, water activities, other recreational or sports activities and leisure activities or relaxing outside. These activities accounted for more than 94% of time spent outdoors both for working and retired men and women. Our data document the feasibility and guidance for developing a short checklist of outdoor activities for use in epidemiologic questionnaires for estimating sunlight exposures of working and retired indoor workers.
PMCID: PMC3956440  PMID: 18643910
14.  The High Prevalence of Vitamin D Deficiency and Its Related Maternal Factors in Pregnant Women in Beijing 
PLoS ONE  2013;8(12):e85081.
Maternal vitamin D deficiency has been suggested to influence fetal and neonatal health. Little is known about vitamin D status in Chinese pregnant women. The purpose of this study was to assess the vitamin D status of pregnant women residing in Beijing in winter and evaluate the impact of maternal factors on serum 25-hydroxyvitamin D [25(OH)D] levels. The study was conducted on 125 healthy pregnant women. For each individual, data concerning pre-pregnancy weight, educational status, use of multivitamins and behavioral factors such as daily duration of computer use, walking and sun exposure were obtained. Serum concentrations of 25(OH)D were measured by enzyme-linked immunosorbent assay. The prevalence of vitamin D deficiency (25(OH)D < 50 nmol/L) was 96.8% and almost half (44.8%) of women were severely vitamin D deficiency (25(OH)D < 25 nmol/L). The concentration of 25(OH)D was lower in women with shorter duration of sun exposure (≤ 0.5 h/day, 25.3 ± 8.9 nmol/L) than that in women with longer duration of sun exposure (> 0.5 h/day; 30.3± 9.5 nmol/L; P = 0.003). Thirty six women (28.8%) had sun exposure duration ≥ 1.5h/day. The 25(OH)D concentration in these women was 31.5 ± 9.4 nmol/L which was also much lower than the normal level. Women who reported taking a multivitamin supplement had significantly higher 25(OH)D concentrations (32.3 ± 9.5 nmol/L) when compared with non-users (24.9 ± 8.2 nmol/L; P < 0.001). Pregnant women in Beijing are at very high risk of vitamin D deficiency in winter. Duration of Sun exposure and the use of multivitamin were the most important determinants for vitamin D status. However, neither prolonging the time of sunlight exposure nor multivitamin supplements can effectively prevent pregnant women from vitamin D deficiency. Other measures might have to be taken for pregnant women to improve their vitamin D status in winter.
PMCID: PMC3873449  PMID: 24386450
15.  Staphylococcus aureus nasal carriage is associated with serum 25-hydroxyvitamin D levels, gender and smoking status. The Tromsø Staph and Skin Study 
Vitamin D induces the expression of antimicrobial peptides with activity against Staphylococcus aureus. Thus, we studied the association between serum 25-hydroxyvitamin D (25(OH)D) and S. aureus nasal colonization and carriage. Nasal swabs, blood samples and clinical data from 2,115 women and 1,674 men, aged 30–87 years, were collected in the Tromsø Staph and Skin Study 2007–08, as part of the population-based sixth Tromsø Study. Multivariate logistic regression analyses were stratified by recognized risk factors for S. aureus carriage: sex, age and smoking. In non-smoking men, we observed a 6.6% and 6.7% decrease in the probability of S. aureus colonization and carriage, respectively, by each 5 nmol/l increase in serum 25(OH)D concentration (P < 0.001 and P = 0.001), and serum 25(OH)D > 59 nmol/l and ≥75 nmol/l as thresholds for ~30% and ~50% reduction in S. aureus colonization and carriage. In non-smoking men aged 44–60 years, the odds ratio for S. aureus colonization was 0.44 (95% confidence interval, 0.28−0.69) in the top tertile of serum 25(OH)D versus the bottom tertile. In women and smokers there were no such associations. Our study supports that serum vitamin D is a determinant of S. aureus colonization and carriage.
PMCID: PMC3303067  PMID: 21811869
16.  Physical Activity and Sex Hormone Levels in Estradiol- and Placebo-Treated Postmenopausal Women 
Menopause (New York, N.Y.)  2011;18(10):1079-1086.
Postmenopausal changes in the hormonal milieu in women with or without hormone therapy (HT) are hypothesized to be the pathway for a number of menopause-associated modifications in physiology and disease risk. Physical activity may modify these changes in women’s hormone profiles. The crucial yet complex relationship between physical activity and physiologic and pharmacologic sex hormone levels in postmenopausal women has not been investigated sufficiently.
Using structured recall, physical activity was assessed longitudinally over two years in 194 postmenopausal women (90 randomized to daily 1 mg 17β-estradiol and 104 to placebo) in the Estrogen in the Prevention of Atherosclerosis Trial. Levels of physical activity were correlated to serum sex hormone and serum hormone-binding globulin (SHBG) levels in each treatment group.
In placebo-treated women, total energy expenditure was positively associated with sex hormone-binding globulin (SHBG) (p<0.001) and inversely associated with testosterones (total, bioavailable, free) and androstenedione (p<0.001 for all), as well as with estradiol (p=0.02). In estradiol-treated women, estradiol levels were inversely associated with total energy expenditure (p=0.002) and weekly hours spent in moderate or more vigorous physical activity (p=0.001).
Physical activity is associated with lower serum levels of estradiol in both HT-treated and untreated women. In placebo-treated women only, physical activity is associated with reduced androgen levels and elevated SHBG levels.
PMCID: PMC3183237  PMID: 21646925
Physical activity; sex hormones; estradiol; menopause
17.  Serum 25-Hydroxyvitamin D Concentrations and Season-Specific Correlates in Japanese Adults 
Journal of Epidemiology  2011;21(5):346-353.
Several lines of evidence indicate an important role for vitamin D in the prevention of a range of diseases. Blood vitamin D levels show clear seasonal variation; however, data on the determinants of vitamin D status for each season are limited. We investigated the association between lifestyle and serum vitamin D concentration by season in Japanese workers.
Subjects were 312 men and 217 women aged 21 to 67 years who worked in municipal offices in Northern Kyushu, Japan and participated in a periodic checkup in July or November. Multiple linear regression analysis was used to examine the association between serum 25-hydroxivitamin D concentrations and lifestyle factors for each season.
Mean serum 25-hydroxyvitamin D concentration was 27.4 ng/ml (68.4 nmol/L) and 21.4 ng/ml (53.4 nmol/L) for workers surveyed in July and November, respectively (P < 0.001); the prevalence of vitamin D deficiency (<20 ng/ml) was 9.3% and 46.7%, respectively (P < 0.001). In November, dietary vitamin D intake (in both sexes) and nonsmoking and physical activity (in men) were significantly associated with higher concentrations of serum 25-hydroxyvitamin D. In summer, fish/shellfish intake was associated with higher serum 25-hydroxyvitamin D concentrations in women.
Vitamin D deficiency is common in Japanese workers during seasons with limited sunlight. The lifestyle correlates of favorable vitamin D status in November were physical activity, dietary vitamin D intake, and nonsmoking.
PMCID: PMC3899433  PMID: 21747209
25-hydroxyvitamin D; Japanese; lifestyle factors; vitamin D intakes
18.  25-Hydroxyvitamin D Concentration, Vitamin D Intake and Joint Symptoms in Postmenopausal Women 
Maturitas  2010;68(1):10.1016/j.maturitas.2010.10.006.
Low 25 hydroxyvitamin D (25(OH) D) concentrations have been associated with radiologic worsening of osteoarthritis in some reports. However, the results are mixed and few studies have evaluated associations between 25(OH) D concentrations and both total vitamin D intake and clinical joint symptoms.
Study Design
Cross-sectional analyses of information from a subset of 1993 postmenopausal women obtained at baseline entry in the Women's Health Initiative Calcium plus Vitamin D clinical trial.
Main Outcome Measures
25(OH) D concentration, total vitamin D intake (diet plus supplements), presence and severity of joint pain and joint swelling.
The 25(OH) D levels were commonly low with 53% having deficient (< 50 nmol/L) and only 17% having sufficient (> 72 nmol/L) levels. Joint pain (reported by 74%) and joint swelling (reported by 34%) were also commonly reported. 25(OH) D concentrations were modestly correlated with total vitamin D intake (R =0.29, P<0.0001); however, considerable variability in 25(OH) D concentrations for a given vitamin D intake was seen. In adjusted linear regression models, lower serum 25(OH) D concentrations were associated with higher average joint pain score (P=0.01 for trend) with differences most apparent in the lowest 25(OH) D levels sextile.
Relatively low 25(OH) D levels and a high frequency of joint symptoms were common in this population of postmenopausal women. Total vitamin D intake was only modestly associated with 25(OH) D. Low serum 25(OH) D concentrations were associated with higher joint pain scores. These findings can inform the design of future intervention trials.
PMCID: PMC3860096  PMID: 21093181
19.  Association between Vitamin D Status and Risk of Metabolic Syndrome among Korean Postmenopausal Women 
PLoS ONE  2014;9(2):e89721.
This study aimed to investigate the association between serum levels of 25-hydroxyvitamin D [25(OH)D] and metabolic syndrome along with its associated risk factors in Korean postmenopausal women. This study was performed using data from the KNHANES 2008–2010 study and included 4,364 postmenopausal Korean women. Clinical and other objective characteristics, seasonality, and presence of metabolic syndrome with its five components were evaluated and correlated with the serum levels of 25(OH)D. Although no statistically significant associations were observed between the levels of serum 25(OH)D and the prevalence of metabolic syndrome, the adjusted OR for elevated blood pressure, elevated triglycerides (TGs), and reduced high-density lipoprotein cholesterol (HDL-C) showed tendency to decrease sequentially as tertiles of serum 25(OH)D levels increased (p for trends  = 0.066, 0.043, and 0.010, respectively). Women in the highest tertile of serum 25(OH)D showed a significant decrease in the prevalence of elevated blood pressure, elevated TGs, and reduced HDL-C as compared with those in the lowest tertile of serum 25(OH)D (p = 0.020, 0.014, and 0.002, respectively). Based on these results, we consider that adequate serum levels of 25(OH)D in Korean postmenopausal women may not entirely indicate a lower risk of developing metabolic syndrome. However, adequate serum levels of 25(OH)D are significantly associated with a decrease in elevated blood pressure, elevated TGs, and reduced HDL-C levels in postmenopausal women.
PMCID: PMC3931824  PMID: 24586986
20.  Intensity of recreational physical activity in different life periods in relation to breast cancer among women in the region of Western Pomerania 
Contemporary Oncology  2013;16(6):576-581.
Recreational physical activity has been consistently associated with lower breast cancer risk, but there is a need to study the intensity and duration of activity that are critical to reduce the risk. The aim of this study was to examine the influence of moderate and vigorous intensity of recreational physical activity performed at different age periods on breast cancer risk.
Material and methods
The case-control study included 858 women with histological confirmation of invasive breast cancer and 1085 women free of any cancer diagnosis, residents of the region of Western Pomerania, aged 28–79 years. The frequency, duration and intensity of lifetime household, occupational and recreational physical activity, sociodemographic characteristics, reproductive factors, family history of breast cancer, current weight and height, and lifestyle habits were measured using a self-administered questionnaire. Unconditional logistic regression analyses were applied to estimate odds ratios (ORs) and 95% confidence intervals (CIs). The risk estimates were controlled for potential risk factors and lifetime household and occupational activities.
We found a risk reduction for recreational activity done early in life (age periods 14–20, 21–34, 35–50 years), particularly at ages 14–20 and 21–34 years, regardless of intensity. Active women engaging in more than 4.5 hours per week of moderate activity during ages 14–20 years had, on average, a 36% lower risk (OR = 0.64, 95% CI: 0.45–0.89) than women who were never or rarely active. For the women who reported 4.5 hours per week of vigorous activity during this period we found about 64% risk reduction (OR = 0.36, 95% CI: 0.26–0.51). For the period after 50 years of age, recreational activity of moderate or vigorous intensity was not significantly associated with the risk.
Recreational physical activity of moderate or vigorous intensity done during adolescence, early and middle adulthood, particularly at ages 14–20 and 21–34 years, is associated with significantly decreased breast cancer risk.
PMCID: PMC3687462  PMID: 23788947
breast cancer; physical activity; prevention; age; intensity; case-control study
21.  Serum 25-Hydroxyvitamin D Concentration is Associated with Functional Capacity in Older Adults with Heart Failure 
American heart journal  2010;160(5):893-899.
Vitamin D is a fat soluble hormone necessary for calcium homeostasis. Recently studies have demonstrated that vitamin D may be important to the health of the cardiovascular system.
Adults ≥ 50 years with HF were recruited for assessment of serum 25-Hydroxyvitamin D (25OHD) concentrations. Cardiopulmonary exercise testing was used to assess functional capacity. Proximal muscle strength was evaluated with a Biodex leg press and health status was assessed with the Kansas City Cardiomyopathy Questionnaire (KCCQ). Univariate associations between physical performance and health status measures and 25OHD followed by a linear regression model were used to study associations, adjusting for other potential explanatory variables.
Forty adults age 67.8 ±10.9 yrs (55% women and 57.5% AA) with mean EF 40% were analyzed (NYHA II in 70% and III in 30%). Co-morbidities included 77.5% HTN, 47.5% diabetes. The mean 25OHD concentration was 18.5 ± 9.1 ng/ml, mean peak VO2 14 ± 4 ml/kg/min. In univariate regression analysis, 25OHD was positively associated with peak VO2 (p=0.045). Multivariable regression analysis sustained positive association between 25OHD and peak VO2 (p=.044), after adjusting for age, race, and respiratory exchange ratio (adjusted R2 = 0.32). Association between proximal muscle strength with the 25OHD concentration was not significant. The KCCQ physical limitation domain score was negatively associated with 25OHD (p=0.04) but was not sustained in multivariable analysis.
25OHD may be an important marker or modulator of functional capacity in patients with HF. Randomized controlled trials are needed to assess the effect of vitamin D repletion on functional performance.
PMCID: PMC2998064  PMID: 21095277
Vitamin D; Heart Failure; Functional Capacity
22.  Prospective study of physical activity and risk of squamous cell carcinoma of the skin 
BMC Cancer  2011;11:516.
The relationship between physical activity and risk of cutaneous squamous cell carcinoma (SCC) is unknown and difficult to investigate due to confounding by sun exposure. We prospectively examined the association of recreational and occupational physical activity and incidence of SCC accounting for photoaging and other risk factors.
We used available information on physical activity from the Australian population-based Nambour Skin Cancer Study comprising 1,171 adults aged 25-75 years at baseline (1992). In sex-stratified analyses (person-based and tumor-based) we estimated the associations between type of activity and incidence of SCC prospectively to 2007.
During 16 years of follow-up, 98 men and 90 women newly developed SCC. We found no significant association between recreational activity measures and SCC after controlling for potential confounding factors including indicators of sun exposure. In men, the observed risk pattern was however suggestive of elevated risk with increasing total hours of recreational activity (compared to inactive men, RR (95%CI) 0.89 (0.54, 1.46) for ≤ 1.5 hrs/wk; 1.29 (0.82, 2.04) for ≤ 4.0 hrs/wk; 1.33 (0.86, 2.05) > 4.0 hrs/wk), while among women, higher level of occupational activity (standing and manual versus sedentary work activities) was associated with a reduced incidence of SCC tumors (P trend = 0.03).
Despite some suggestion that recreational activity in men and occupational activity in women are related to occurrence of SCC, there is no firm support for a role of physical activity in the development of cutaneous SCC.
PMCID: PMC3265437  PMID: 22165995
23.  Association of serum 25-OHD concentrations with maternal sex-steroids and IGF-1 hormones during pregnancy 
Cancer causes & control : CCC  2011;22(6):925-928.
Vitamin D may influence circulating levels of sex-steroid hormones in women during reproductive life, but associations in pregnant women have not been explored.
Correlation and linear regression models were used to assess the association between sex-steroids, (estradiol, progesterone, 17-hydroxyprogesterone, testosterone and androstenedione), IGF-I and serum 25-hydroxyvitamin D (25-OHD) concentrations during the first trimester of pregnancy in 106 cancer free women from the Finnish Maternity Cohort.
There was no significant association of serum 25-OHD with any of the hormones measured. One unit increase in serum 25-OHD concentration was associated with a non-significant 6% increase in estradiol concentrations. Multiparous women had higher levels of vitamin D (40.4 vs. 32.9 nmol/L, p-value =0.01) than primiparous women.
Our study does not support an association between maternal serum 25-OHD levels and sex steroids or IGF-I concentrations during the first trimester of pregnancy.
PMCID: PMC3131105  PMID: 21387179
Vitamin D; estradiol; progesterone; testosterone; androstenedione; IGF-1; sex-steroid hormones; pregnancy
24.  Does Hormone Therapy Counter the Beneficial Effects of Physical Activity on Breast Cancer Risk in Postmenopausal Women? 
Cancer causes & control : CCC  2011;22(3):515-522.
Studies consistently demonstrate that physical activity is inversely associated with postmenopausal breast cancer. Whether this association is stronger among non-hormone users or former users of menopausal hormone therapy (HT) is of interest given the marked decline in HT use since 2002.
The Women’s Contraceptive and Reproductive Experiences Study, a population-based case-control study of invasive breast cancer, recruited white women and black women ages 35–64 years, and collected histories of lifetime recreational physical activity and HT use including estrogen-alone therapy (ET) and estrogen plus progestin therapy (EPT).
Among postmenopausal women (1908 cases, 2013 control participants), breast cancer risk declined with increasing levels of lifetime physical activity among never HT users; among short-term HT users (fewer than 5 years); and current ET users; Ptrend values ranged from 0.004 to 0.016. In contrast, physical activity had no significant association with risk among long-term and past HT users and among current EPT users. No statistical evidence of heterogeneity was demonstrated for duration or currency of HT use.
Breast cancer risk decreases with increasing lifetime physical activity levels among postmenopausal women who have not used HT, have used HT for less than 5 years, or are current ET users yet this study was unable to demonstrate statistically that HT use modifies the relationship between physical activity and breast cancer. With profound changes in HT use occurring since 2002, it will be important in future studies to learn whether or not any association between physical activity and breast cancer among former HT users is a function of time since last HT use.
PMCID: PMC3229264  PMID: 21213036
Hormone therapy; physical activity; breast cancer
25.  Housework Reduces All-Cause and Cancer Mortality in Chinese Men 
PLoS ONE  2013;8(5):e61529.
Leisure time physical activity has been extensively studied. However, the health benefits of non-leisure time physical activity, particular those undertaken at home on all-cause and cancer mortality are limited, particularly among the elderly.
We studied physical activity in relation to all-cause and cancer mortality in a cohort of 4,000 community-dwelling elderly aged 65 and older. Leisure time physical activity (sport/recreational activity and lawn work/yard care/gardening) and non-leisure time physical activity (housework, home repairs and caring for another person) were self-reported on the Physical Activity Scale for the Elderly. Subjects with heart diseases, stroke, cancer or diabetes at baseline were excluded (n = 1,133).
Among the 2,867 subjects with a mean age of 72 years at baseline, 452 died from all-cause and 185 died from cancer during the follow-up period (2001–2012). With the adjustment for age, education level and lifestyle factors, we found an inverse association between risk of all-cause mortality and heavy housework among men, with the adjusted hazard ratio (HR) of 0.72 (95%CI = 0.57–0.92). Further adjustment for BMI, frailty index, living arrangement, and leisure time activity did not change the result (HR = 0.71, 95%CI = 0.56–0.91). Among women, however, heavy housework was not associated with all-cause mortality. The risk of cancer mortality was significantly lower among men who participated in heavy housework (HR = 0.52, 95%CI = 0.35–0.78), whereas among women the risk was not significant. Men participated in light housework also were at lower risk of cancer mortality than were their counterparts, however, the association was not significant. Leisure time physical activity was not related to all-cause or cancer mortality in either men or women.
Heavy housework is associated with reduced mortality and cancer deaths over a 9-year period. The underlying mechanism needs further study.
PMCID: PMC3647044  PMID: 23667441

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