Background. The Free Radical Theory of Aging mechanistically links oxidative stress to aging. Okinawa has among the world's longest-lived populations but oxidative stress in this population has not been well characterized. Methods. We compared plasma lipid peroxide (LPO) and vitamin E—plasma and intracellular tocopherol levels (total α, β, and γ), in centenarians with younger controls. Results. Both LPO and vitamin E tocopherols were lower in centenarians, with the exception of intracellular β-tocopherol, which was significantly higher in centenarians versus younger controls. There were no significant differences between age groups for tocopherol: cholesterol and tocopherol: LPO ratios. Correlations were found between α-Tocopherol and LPO in septuagenarians but not in centenarians. Conclusions. The low plasma level of LPO in Okinawan centenarians, compared to younger controls, argues for protection against oxidative stress in the centenarian population and is consistent with the predictions of the Free Radical Theory of Aging. However, the present work does not strongly support a role for vitamin E in this phenomenon. The role of intracellular β-tocopherol deserves additional study. More research is needed on the contribution of oxidative stress and antioxidants to human longevity.
Few previous studies have reported the association of aortic stiffness with marine n-3 fatty acids (Fas) in the general population. The aim of this study was to determine the combined and independent associations of 2 major marine n-3 FAs, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), with aortic stiffness evaluated using carotid–femoral pulse wave velocity (cfPWV) in Korean, white, and Japanese American men.
A population-based sample of 851 middle-aged men (299 Koreans, 266 whites, and 286 Japanese Americans) was examined for cfPWV during 2002–2006. Serum FAs, including EPA and DHA, were measured as a percentage of total FAs using gas chromatography. Multiple regression analysis was used to examine the association of EPA and DHA with cfPWV after adjusting for blood pressure and other confounders.
Mean EPA and DHA levels were 1.9 (SD = 1.0) and 4.8 (SD = 1.4) for Koreans, 0.8 (SD = 0.6) and 2.4 (SD = 1.2) for whites, and 1.0 (SD = 1.0) and 3.2 (SD = 1.4) for Japanese Americans. Both EPA and DHA were significantly higher in Koreans than in the other 2 groups (P < 0.01). Multiple regression analyses in Koreans showed that cfPWV had a significant inverse association with total marine n-3 FAs and with EPA alone after adjusting for blood pressure and other potential confounders. In contrast, there was no significant association of cfPWV with DHA. Whites and Japanese Americans did not show any significant associations of cfPWV with total marine n-3 FAs, EPA, or DHA.
High levels of EPA observed in Koreans have an inverse association with aortic stiffness.
aortic stiffness; blood pressure; carotid femoral pulse wave velocity; docosahexaenoic acid; eicosapentaenoic acid; fish oil; hypertension.
Mortality from coronary heart disease (CHD) in women in Japan is one of the lowest in developed countries. In an attempt to shed some light on possible reasons of lower CHD in women in Japan compared with the United States, we extensively reviewed and analyzed existing national data and recent literature.
We searched recent epidemiological studies that reported incidence of acute myocardial infarction (AMI) and examined risk factors for CHD in women in Japan. Then, we compared trends in risk factors between women currently aged 50–69 years in Japan and the United States, using national statistics and other available resources.
Recent epidemiological studies have clearly shown that AMI incidence in women in Japan is lower than that reported from other countries, and that lipids, blood pressure (BP), diabetes, smoking, and early menopause are independent risk factors. Comparing trends in risk factors between women in Japan and the United States, current levels of serum total cholesterol are higher in women in Japan and levels have been similar at least since 1990. Levels of BP have been higher in in Japan for the past 3 decades. Prevalence of type 2 diabetes has been similar in Japanese and white women currently aged 60–69 for the past 2 decades. In contrast, rates of cigarette smoking, although low in women in both countries, have been lower in women in Japan.
Differences in risk factors and their trends are unlikely to explain the difference in CHD rates in women in Japan and the United States. Determining the currently unknown factors responsible for low CHD mortality in women in Japan may lead to new strategy for CHD prevention.
Conflicting evidence exists regarding whether obesity is independently associated with coronary artery calcium (CAC), a measure of coronary atherosclerosis. We examined an independent association of obesity with prevalent CAC among samples of multi-ethnic groups whose background populations have varying levels of obesity and coronary heart disease (CHD).
Methods and results
We analysed a population-based sample of 1212 men, aged 40–49 years free of clinical cardiovascular disease recruited in 2002–06; 310 Japanese in Japan (JJ), 294 Koreans in South Korea (KN), 300 Japanese Americans (JA), and 308 Whites in the USA (UW). We defined prevalent CAC as an Agatston score of ≥10. Prevalent CAC was calculated by tertile of the body mass index (BMI) in each ethnic group and was plotted against the corresponding median of tertile BMI. Additionally, logistic regression was conducted to examine whether an association of the BMI was independent of conventional risk factors. The median BMI and crude prevalence of CAC for JJ, KN, JA, and UW were 23.4, 24.4, 27.4, and 27.1 (kg/m2); 12, 11, 32, and 26 (%), respectively. Despite the absolute difference in levels of BMI and CAC across groups, higher BMI was generally associated with higher prevalent CAC in each group. After adjusting for age, smoking, alcohol, hypertension, lipids, and diabetes mellitus, the BMI was positively and independently associated with prevalent CAC in JJ, KN, UW, but not in JA.
In this multi-ethnic study, obesity was independently associated with subclinical stage of coronary atherosclerosis among men aged 40–49 years regardless of the BMI level.
Coronary artery calcium; Obesity; Body mass index; Multi-ethnic; Men; Risk factors
We examined the association between serum lipoprotein subclasses and the three measures of arterial stiffness i.e. (i) carotid-femoral pulse wave velocity (cfPWV) which is a gold standard measure of central arterial stiffness, (ii) brachial-ankle PWV (baPWV) which is emerging as a combined measure of central and peripheral arterial stiffness, and (iii) femoral-ankle PWV (faPWV) which is a measure of peripheral arterial stiffness. Among a population-based sample of 701 apparently healthy Caucasian, Japanese American and Korean men aged 40–49 years, concentrations of lipoprotein particles were assessed by nuclear magnetic resonance (NMR) spectroscopy, and PWV was assessed with an automated waveform analyzer (VP2000, Omron, Japan). Multiple linear regressions were performed to analyze the association between each NMR lipoprotein subclasses and PWV measures, after adjusting for cardiovascular risk factors and other confounders. A cut-off of p<0.01 was used for determining significance. All PWV measures had significant correlations with total and small low-density lipoprotein particle number (LDL-P) (all p<0.0001) but not LDL-cholesterol (LDL-C) (all p>0.1), independent of race and age. In multivariate regression analysis, no NMR lipoprotein subclass was significantly associated with cfPWV (all p>0.01). However, most NMR lipoprotein subclasses had significant associations with both baPWV and faPWV (p<0.01). In this study of healthy middle-aged men, as compared to cfPWV, both baPWV and faPWV had stronger associations with particle numbers of lipoprotein subclasses. Our results may suggest that both baPWV and faPWV are related to arterial stiffness and atherosclerosis, whereas cfPWV may represent arterial stiffness alone.
lipoproteins; lipoprotein fractions; pulse wave velocity; atherosclerosis
Both indices of obesity and lipoprotein subfractions contribute to
coronary heart disease risk. However, associations between indices of
obesity and lipoprotein subfractions remain undetermined across different
ethnic groups. This study aims to examine the associations of indices of
obesity in Japanese Americans (JA), African Americans (AA) and Koreans with
A population-based sample of 230 JA, 91 AA, and 291 Korean men aged
40–49 was examined for indices of obesity, i.e., visceral and
subcutaneous adipose tissue (VAT and SAT, respectively), waist circumference
(WC), and body-mass index (BMI), and for lipoprotein subfractions by
nuclear-magnetic-resonance spectroscopy. Multiple regression analyses were
performed in each of the three ethnic groups to examine the associations of
each index of obesity with lipoprotein.
VAT had significant positive associations with total and small
low-density lipoprotein (LDL) and a significant negative association with
large high-density lipoprotein (HDL) in all three ethnicities (p < 0.01).
SAT, WC, and BMI had significant positive associations with total and small
LDL in only JA and Koreans, while these indices had significant inverse
associations with large HDL in all ethnic groups (p < 0.01). Compared to
SAT, VAT had larger R2 values in the
associations with total and small LDL and large HDL in all three ethnic
VAT is significantly associated with total and small LDL and large
HDL in all three ethnic groups. The associations of SAT, WC, and BMI with
lipoprotein subfractions are weaker compared to VAT in all three ethnic
visceral adipose tissue; subcutaneous adipose tissue; body-mass index; waist circumference; lipoprotein subfractions
To determine the relation between height, FOXO3 genotype and age of death in humans.
Observational study of 8,003 American men of Japanese ancestry from the Honolulu Heart Program/Honolulu-Asia Aging Study (HHP/HAAS), a genetically and culturally homogeneous cohort followed for over 40 years. A Cox regression model with age as the time scale, stratified by year of birth, was used to estimate the effect of baseline height on mortality during follow-up. An analysis of height and longevity-associated variants of the key regulatory gene in the insulin/IGF-1 signaling (IIS) pathway, FOXO3, was performed in a HHP-HAAS subpopulation. A study of fasting insulin level and height was conducted in another HHP-HAAS subpopulation.
A positive association was found between baseline height and all-cause mortality (RR = 1.007; 95% CI 1.003–1.011; P = 0.002) over the follow-up period. Adjustments for possible confounding variables reduced this association only slightly (RR = 1.006; 95% CI 1.002–1.010; P = 0.007). In addition, height was positively associated with all cancer mortality and mortality from cancer unrelated to smoking. A Cox regression model with time-dependent covariates showed that relative risk for baseline height on mortality increased as the population aged. Comparison of genotypes of a longevity-associated single nucleotide polymorphism in FOXO3 showed that the longevity allele was inversely associated with height. This finding was consistent with prior findings in model organisms of aging. Height was also positively associated with fasting blood insulin level, a risk factor for mortality. Regression analysis of fasting insulin level (mIU/L) on height (cm) adjusting for the age both data were collected yielded a regression coefficient of 0.26 (95% CI 0.10–0.42; P = 0.001).
Height in mid-life is positively associated with mortality, with shorter stature predicting longer lifespan. Height was, moreover, associated with fasting insulin level and the longevity genotype of FOXO3, consistent with a mechanistic role for the IIS pathway.
To determine whether serum levels of long-chain n-3 polyunsaturated fatty acids (LCn3PUFAs) contribute to the difference in incidence rate of coronary artery calcification (CAC) between Japanese in Japan and U.S. whites.
In a population-based prospective-cohort study, 214 Japanese and 152 white men aged 40–49 years at baseline (2002–2006) with coronary calcium score (CCS) = 0 were reexamined for CAC in 2007–2010. Among these, 175 Japanese and 113 whites participated in the follow-up exam. Incident cases were defined as participants with CCS ≥ 10 at follow-up. A relative risk regression analysis was used to model incidence rate ratio between Japanese and whites. The incidence rate ratio was first adjusted for potential confounders at baseline and then further adjusted for serum LCn3PUFAs at baseline.
Mean (standard deviation) serum percentage of LCn3PUFA was > 100% higher in Japanese than in whites (9.08 (2.49) versus 3.84 (1.79), respectively, p<0.01). Japanese had a significantly lower incidence rate of CAC compared to whites (0.9 versus 2.9/100 person-years, respectively, p < 0.01). Incidence rate ratio of CAC taking follow-up time into account between Japanese and white men was 0.321 (95% confidence interval (CI) 0.150, 0.690: p<0.01). After adjusting for age, systolic-blood pressure, low-density-lipoprotein cholesterol, diabetes, and other potential confounders, the ratio remained significant: 0.262 (95% CI: 0.094, 0.731, p=0.01). After further adjusting for LCn3PUFAs, however, the ratio was attenuated and became non-significant (0.376 (95% CI: 0.090, 1.572, p=0.18).
LCn3PUFAs significantly contributed to the difference in CAC incidence between Japanese and white men.
long-chain n-3 fatty acids; coronary artery calcification; prospective cohort study; incidence; risk factors
Both carotid-femoral (cf) pulse wave velocity (PWV) and brachial-ankle (ba) PWV employ arterial sites that are not consistent with the path of blood flow. Few previous studies have reported the differential characteristics between cfPWV and baPWV by simultaneously comparing these with measures of pure central (aorta) and peripheral (leg) arterial stiffness, i.e., heart-femoral (hf) PWV and femoral-ankle (fa) PWV in healthy populations. We aimed to identify the degree to which these commonly used measures of cfPWV and baPWV correlate with hfPWV and faPWV, respectively, and to evaluate whether both cfPWV and baPWV are consistent with either hfPWV or faPWV in their associations with cardiovascular (CV) risk factors.
A population-based sample of healthy 784 men aged 40–49 (202 white Americans, 68 African Americans, 202 Japanese-Americans, and 282 Koreans) was examined in this cross-sectional study. Four regional PWVs were simultaneously measured by an automated tonometry/plethysmography system.
cfPWV correlated strongly with hfPWV (r = .81, P < .001), but weakly with faPWV (r = .12, P = .001). baPWV correlated moderately with both hfPWV (r = .47, P < .001) and faPWV (r = .62, P < .001). After stepwise regression analyses with adjustments for race, cfPWV shared common significant correlates with both hfPWV and faPWV: systolic blood pressure (BP) and body mass index (BMI). However, BMI was positively associated with hfPWV and cfPWV, and negatively associated with faPWV. baPWV shared common significant correlates with hfPWV: age and systolic BP. baPWV also shared the following correlates with faPWV: systolic BP, triglycerides, and current smoking.
Among healthy men aged 40 – 49, cfPWV correlated strongly with central PWV, and baPWV correlated with both central and peripheral PWVs. Of the CV risk factors, systolic BP was uniformly associated with all the regional PWVs. In the associations with factors other than systolic BP, cfPWV was consistent with central PWV, while baPWV was consistent with both central and peripheral PWVs.
Arterial stiffness; Aorta; Carotid arteries; Brachial artery; Femoral artery
FOXO3 is generally recognized as a “master” gene in aging since its association with longevity has been replicated in multiple organisms and human populations. A group of single nucleotide polymorphisms in linkage disequilibrium with a coding region has been associated with human longevity, but the actual functional variant is unidentified. Therefore, we sequenced the coding region in our long-lived Japanese American population in order to enhance resources for fine mapping this region. We demonstrate that of 38 published variants, 6 are misalignments with homologous nonallelic sequences from FOXO3B (ZNF286B), a pseudogene on a different chromosome; 2 are attributable to ZNF286B only, and the remaining 30 were unconfirmed, indicating that they are very rare and not likely involved in longevity. Furthermore, we identified a novel, unique, nonsynonymous coding variant in exon 3 (Gly566Ala; rs138174682) that is prevalent in multiple ethnic groups but appeared too rare for major longevity effects in our study populations.
Aging; FOXO3; Genetic; Human longevity
In the 1990’s Iceland and Japan were known as countries with high fish consumption whereas coronary heart disease (CHD) mortality in Iceland was high and that in Japan was low among developed countries. We described recent data fish consumption and CHD mortality from publicly available data. We also measured CHD risk factors and serum levels of marine-derived n-3 and other fatty acids from population-based samples of 1,324 men in Iceland, Japan, South Korea, and the US. CHD mortality in men in Iceland was almost 3 times as high as that in Japan and South Korea. Generally a profile of CHD risk factors in Icelanders compared to Japanese was more favorable. Serum marine-derived n-3 fatty acids in Iceland were significantly lower than in Japan and South Korea but significantly higher than in the US.
n-3 fatty acids; eicosapentaenoic acid; docosaehexaenoic acid; coronary heart disease; descriptive epidemiologic study
Explanations for the low prevalence of atherosclerosis in Japan versus United States are often confounded with genetic variation. To help remove such confounding, coronary artery calcification (CAC), a marker of subclinical atherosclerosis, was compared between Japanese men in Japan and Japanese men in Hawaii. Findings are based on risk factor and CAC measurements that were made from 2001 to 2005 in 311 men in Japan and 300 men in Hawaii. Men were aged 40 to 50 years and without cardiovascular disease. After age-adjustment, there was a 3-fold excess in the odds of prevalent CAC scores ≥10 in Hawaii versus Japan (relative odds [RO] = 3.2; 95% confidence interval [CI] = 2.1,4.9). While men in Hawaii had a generally poorer risk factor profile, men in Japan were 4-times more likely to smoke cigarettes (49.5 vs. 12.7%, p<0.001). In spite of marked risk factor differences between the samples, none of the risk factors provided an explanation for the low amounts of CAC in Japan. After risk factor adjustment, the RO of CAC scores ≥10 in Hawaii versus Japan was 4.0 (95% CI = 2.2,7.4). Further studies are needed to identify factors that offer protection against atherosclerosis in Japanese men in Japan.
Atherosclerosis; cohort studies; coronary disease; Japan; men; risk factors
The study aim was to test whether the metabolic syndrome or its components predicted cognitive decline among persons aged 80 years and older (mean 85.0 years). Participants were members of the “Keys to Optimal Cognitive Aging Project,” a prospective cohort study in Okinawa, Japan. Metabolic syndrome was assessed at baseline. Cognitive functions were assessed annually for up to 3 years. One hundred and forty-eight participants completed at least one follow-up with 101 participating in all three assessments and 47 participating in two of the three assessments. The mean and median duration of follow-up were 1.8 and 2 years, respectively. Metabolic syndrome and four components were not associated with decline in global and executive cognitive functions. However, high glycosylated hemoglobin was associated with decline in memory function at the second follow-up. Our study supports accumulating evidence that the positive association between metabolic syndrome and cognitive function might not hold for the oldest old.
Metabolic syndrome; Cognitive decline; Oldest old; Longitudinal study; Okinawa
Epidemiologic studies of pancreatic cancer risk have reported null or non-significant positive associations for obesity, while associations for height have been null. Waist and hip circumference have been evaluated infrequently.
A pooled analysis of 14 cohort studies on 846,340 individuals was conducted; 2,135 individuals were diagnosed with pancreatic cancer during follow-up. Study-specific relative risks (RRs) and 95% confidence intervals (CIs) were calculated by Cox proportional hazards models, and then pooled using a random effects model.
Compared to individuals with a body mass index (BMI) at baseline between 21–22.9kg/m2, pancreatic cancer risk was 47% higher (95%CI:23–75%) among obese (BMI≥30kg/m2) individuals. A positive association was observed for BMI in early adulthood (pooled multivariate [MV]RR = 1.30, 95%CI=1.09–1.56 comparing BMI≥25kg/m2 to a BMI between 21–22.9kg/m2). Compared to individuals who were not overweight in early adulthood (BMI<25kg/m2) and not obese at baseline (BMI<30kg/m2), pancreatic cancer risk was 54% higher (95%CI=24–93%) for those who were overweight in early adulthood and obese at baseline. We observed a 40% higher risk among individuals who had gained BMI ≥10kg/m2 between BMI at baseline and younger ages compared to individuals whose BMI remained stable. Results were either similar or slightly stronger among never smokers. A positive association was observed between waist to hip ratio (WHR) and pancreatic cancer risk (pooled MVRR=1.35 comparing the highest versus lowest quartile, 95%CI=1.03–1.78).
BMI and WHR were positively associated with pancreatic cancer risk. Maintaining normal body weight may offer a feasible approach to reducing morbidity and mortality from pancreatic cancer.
Pancreatic Cancer; Anthropometry; Pooled Analysis
A high body-mass index (BMI, the weight in kilograms divided by the square of the height in meters) is associated with increased mortality from cardiovascular disease and certain cancers, but the precise relationship between BMI and all-cause mortality remains uncertain.
We used Cox regression to estimate hazard ratios and 95% confidence intervals for an association between BMI and all-cause mortality, adjusting for age, study, physical activity, alcohol consumption, education, and marital status in pooled data from 19 prospective studies encompassing 1.46 million white adults, 19 to 84 years of age (median, 58).
The median baseline BMI was 26.2. During a median follow-up period of 10 years (range, 5 to 28), 160,087 deaths were identified. Among healthy participants who never smoked, there was a J-shaped relationship between BMI and all-cause mortality. With a BMI of 22.5 to 24.9 as the reference category, hazard ratios among women were 1.47 (95 percent confidence interval [CI], 1.33 to 1.62) for a BMI of 15.0 to 18.4; 1.14 (95% CI, 1.07 to 1.22) for a BMI of 18.5 to 19.9; 1.00 (95% CI, 0.96 to 1.04) for a BMI of 20.0 to 22.4; 1.13 (95% CI, 1.09 to 1.17) for a BMI of 25.0 to 29.9; 1.44 (95% CI, 1.38 to 1.50) for a BMI of 30.0 to 34.9; 1.88 (95% CI, 1.77 to 2.00) for a BMI of 35.0 to 39.9; and 2.51 (95% CI, 2.30 to 2.73) for a BMI of 40.0 to 49.9. In general, the hazard ratios for the men were similar. Hazard ratios for a BMI below 20.0 were attenuated with longer-term follow-up.
In white adults, overweight and obesity (and possibly underweight) are associated with increased all-cause mortality. All-cause mortality is generally lowest with a BMI of 20.0 to 24.9.
We studied prospectively the midlife handgrip strength, living habits, and parents’ longevity as predictors of length of life up to becoming a centenarian. The participants were 2,239 men from the Honolulu Heart Program/Honolulu–Asia Aging Study who were born before the end of June 1909 and who took part in baseline physical assessment in 1965–1968, when they were 56–68 years old. Deaths were followed until the end of June 2009 for 44 years with complete ascertainment. Longevity was categorized as centenarian (≥100 years, n = 47), nonagenarian (90–99 years, n = 545), octogenarian (80–89 years, n = 847), and ≤79 years (n = 801, reference). The average survival after baseline was 20.8 years (SD = 9.62). Compared with people who died at the age of ≤79 years, centenarians belonged 2.5 times (odds ratio (OR) = 2.52, 95% confidence interval (CI) = 1.23–5.10) more often to the highest third of grip strength in midlife, were never smokers (OR = 5.75 95% CI = 3.06–10.80), had participated in physical activity outside work (OR = 1.13 per daily hour, 95% CI = 1.02–1.25), and had a long-lived mother (≥80 vs. ≤60 years, OR = 2.3, 95% CI = 1.06–5.01). Associations for nonagenarians and octogenarians were parallel, but weaker. Multivariate modeling showed that mother’s longevity and offspring’s grip strength operated through the same or overlapping pathway to longevity. High midlife grip strength and long-lived mother may indicate resilience to aging, which, combined with healthy lifestyle, increases the probability of extreme longevity.
Aging; Longevity; Inter-generational; Grip strength; Mortality; Human; Life Sciences; Molecular Medicine; Geriatrics/Gerontology; Cell Biology
Objectives. To investigate the reliability and correlations with age of the balance components of the EPESE, NHANES, and the Good Balance Platform System (GBPS) in a normal population of adults.
Setting. Urban Medical Center in the Pacific.
Participants. A random sample of 203 healthy offspring of Honolulu Heart Program participants, ages 38–71.
Measurements. Subjects were examined twice at visits one week apart using the balance components of the EPESE, NHANES, and the good balance system tests.
Results. The EPESE and NHANES batteries of tests were not sufficiently challenging to allow successful discrimination among subjects in good health, even older subjects. The GBPS allowed objective quantitative measurements, but the test-retest correlations generally were not high. The GBPS variables correlated with age only when subjects stood on a foam pad; they also were correlated with anthropometric variables. Conclusion. Both EPESE and NHANES balance tests were too easy for healthy subjects. The GBPS had generally low reliability coefficients except for the most difficult testing condition (foam pad, eyes closed). Both height and body fat were associated with GBPS scores, necessitating adjusting for these variables if using balance as a predictor of future health.
Although animal experiments have consistently demonstrated a positive relationship between breast cancer and energy intake, evidence from human studies remains inconclusive. In the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial cohort, 29,170 women, aged 55–75 years, who successfully completed a food frequency questionnaire (FFQ) at entry (1993–2001), were followed through 2007; 1,319 incident breast cancers were ascertained (median time from FFQ completion to diagnosis, 4.4 y). Women in the highest quartile of energy intake, relative to the lowest, had modestly, but significantly, increased breast cancer risk [multivariate relative risk (RR), 1.21; 95% confidence interval (95% CI), 1.03–1.42; Ptrend = 0.03]. Including body mass index and physical activity in the model reduced risk slightly (RR, 1.18; 95% CI, 1.00–1.39; Ptrend = 0.07). However, in similar analyses using energy intake from a FFQ administered approximately 5 years after entry (27,428 women; 806 incident breast cancers; median time from FFQ completion to diagnosis, 2.7 y), women in the highest and lowest quartiles of energy intake had similar risk. When follow-up time after the first FFQ was divided into three four-year periods, the multivariate RRs for high versus low energy intake increased from 1.21 to 1.37 to 1.55 with increasing time since dietary assessment. Although the divergent results for the two FFQs could be due to subtle questionnaire differences, our findings suggest a modest positive association between energy intake and postmenopausal breast cancer that strengthens with time since dietary assessment.
breast cancer; energy intake; energy balance; cohort
Linkage disequilibrium (LD) is an important measure used in the analysis of single-nucleotide polymorphism (SNP) data. We used the Genetic Analysis Workshop 16 (GAW16) Framingham Heart Study 500 k SNP data to explore the effect of sampling methods on estimating of LD for SNP data.
Method and data
We found 332 trios in the GAW16 Framingham SNP data. Repeated random samples without replacement, of different sizes of trios and independent individuals, are drawn from these 332 trios. For each sample, the LD is calculated using the Haploview program for the chromosome 1 SNP data. Percents of D' > 0.8 and r2 > 0.8 are calculated for different distance bins based on the Haploview output. The results are summarized by sample size and sampling methods to give us an overall view of the effect of sample size and sampling methods on the LD estimation.
Trios design gave stable estimates. A sample of 30 to 40 trios gave estimates of percent of LD > 0.8 very close to those from 332 trios. When independent individuals are used, the estimates are less stable and are different from those obtained from the 332 trios for both D' and r2, with larger differences for D'.
Our results suggest that trio design gives a stable estimate of LD. Therefore it may be more suitable for LD analysis than using independent individuals. We must be cautious when comparing the LD estimates from trios, and those from independent individuals.
To examine whether marine-derived n-3 fatty acids (FAs) are associated with less atherosclerosis in Japanese than Whites in the United States.
Marine-derived n-3 FAs at low levels are cardioprotective through their anti-arrhythmic effect.
A population-based cross-sectional study in 281 Japanese, 306 White, and 281 Japanese American men aged 40–49 was conducted to assess intima-media thickness of the carotid artery (IMT), coronary artery calcification (CAC), and serum FAs.
Japanese in Japan had the lowest levels of atherosclerosis whereas Whites and Japanese Americans had similar levels. Japanese in Japan had twofold higher levels of marine-derived n-3 FAs than Whites and Japanese Americans. Japanese in Japan had significant and non-significant inverse associations of marine-derived n-3 FAs with IMT and CAC prevalence, respectively. The significant inverse association with IMT remained after adjusting for traditional cardiovascular risk factors. Neither Whites nor Japanese Americans had such associations. Significant differences between Japanese in Japan and Whites in multivariable-adjusted IMT (mean difference 39 μm (95% confidence interval (CI), 21 to 57), p<0.001) and CAC prevalence (mean difference 10.7% (95% CI, 2.9 to 18.4), p=0.007) became non-significant after further adjusting for marine-derived n-3 FAs (22 μm (95% CI, −1 to 46), p=0.065 and 5.0 % (95% CI, −5.3 to 15.4), p=0.341, respectively).
Very high levels of marine-derived n-3 FAs have anti-atherogenic properties independent of traditional cardiovascular risk factors and may contribute to lower burden of atherosclerosis in Japanese in Japan, which is unlikely due to genetic factors.
Atherosclerosis; epidemiology; n-3 fatty acids; coronary artery calcification; intima-media thickness; Japanese
Centenarians represent a rare phenotype appearing in roughly 10–20 per 100,000 persons in most industrialized countries but as high as 40–50 per 100,000 persons in Okinawa, Japan. Siblings of centenarians in Okinawa have been found to have cumulative survival advantages such that female centenarian siblings have a 2.58-fold likelihood and male siblings a 5.43-fold likelihood (versus their birth cohorts) of reaching the age of 90 years. This is indicative of a strong familial component to longevity. Centenarians may live such extraordinarily long lives in large part due to genetic variations that either affect the rate of aging and/or have genes that result in decreased susceptibility to age-associated diseases. Some of the most promising candidate genes appear to be those involved in regulatory pathways such as insulin signaling, immunoinflammatory response, stress resistance or cardiovascular function. Although gene variants with large beneficial effects have been suggested to exist, only APOE, an important regulator of lipoproteins has been consistently associated with a longer human lifespan across numerous populations. As longevity is a very complex trait, several issues challenge our ability to identify its genetic influences, such as control for environmental confounders across time, the lack of precise phenotypes of aging and longevity, statistical power, study design and availability of appropriate study populations. Genetic studies on the Okinawan population suggest that Okinawans are a genetically distinct group that has several characteristics of a founder population, including less genetic diversity, and clustering of specific gene variants, some of which may be related to longevity. Further work on this population and other genetic isolates would be of significant interest to the genetics of human longevity.
longevity; genetics; centenarians; Okinawa; longevity genes