African Americans (AAs) and Hispanic/Latinos (HLs) have higher risk of obesity than European Americans, possibly due to differences in environment and lifestyle, but also reflecting differences in ...genetic background.
To gain insight into factors contributing to BMI (in kg/m2) and obesity risk (BMI ≥ 30) among ancestry groups, we investigate the role of self-reported ancestry, proportion of genetic African ancestry, and country of birth in 6368 self-identified AA and 7569 HL participants of the New York–based BioMe Biobank.
AAs and HLs are admixed populations that trace their genetic ancestry to the Americas, Africa, and Europe. The proportion of African ancestry (PAA), quantified using ADMIXTURE, was higher among self-reported AA (median: 87%; IQR: 79–92%) than among HL (26%; 15–41%) participants. Approximately 18% of AA and 59% of HL participants were non–US-born.
Because of significant differences between sexes (PPAA*sex interaction = 4.8 × 10−22), we considered women and men separately. Among women, country of birth and genetic ancestry contributed independently to BMI. US-born women had a BMI 1.99 higher than those born abroad (P = 7.7 × 10−25). Every 10% increase in PAA was associated with a BMI 0.29 higher (P = 7.1 × 10−10). After accounting for PAA and country of birth, the contribution of self-reported ancestry was small (P = 0.046). The contribution of PAA to higher BMI was significantly more pronounced among US-born (0.35/10%PAA, P = 0.003) than among non–US-born (0.26/10%PAA, P = 0.01) women (PPAA*sex interaction = 0.004). In contrast, among men, only US-born status influenced BMI. US-born men had a BMI 1.33 higher than non–US-born men, whereas PAA and self-reported ancestry were not associated with BMI. Associations with obesity risk were similar to those observed for BMI.
Being US-born is associated with a substantially higher BMI and risk of obesity in both men and women. Genetic ancestry, but not self-reported ancestry, is associated with obesity susceptibility, but only among US-born women in this New York–based population.
Aims/hypothesis
At the same level of BMI, white people have less visceral adipose tissue (VAT) and are less susceptible to developing type 2 diabetes than Japanese people. No previous ...population-based studies have compared insulin resistance and insulin secretion between these two races in a standardised manner that accounts for VAT. We compared HOMA-IR, HOMA of beta cell function (HOMA-β%) and disposition index (DI) in US white men and Japanese men in Japan.
Methods
We conducted a population-based, cross-sectional study, comprising 298 white men and 294 Japanese men aged 40–49 years without diabetes. Insulin, glucose, VAT and other measurements were performed at the University of Pittsburgh. We used ANCOVA to compare geometric means of HOMA-IR, HOMA-β% and DI, adjusting for VAT and other covariates.
Results
White men had higher HOMA-IR, HOMA-β% and DI than Japanese men, and the difference remained significant (
p
< 0.01) after adjusting for VAT (geometric mean 95% CI): 3.1 (2.9, 3.2) vs 2.5 (2.4, 2.6), 130.8 (124.6, 137.3) vs 86.7 (82.5, 91.0), and 42.4 (41.0, 44.0) vs 34.8 (33.6, 36.0), respectively. Moreover, HOMA-IR, HOMA-β% and DI were significantly higher in white men even after further adjustment for BMI, impaired fasting glucose and other risk factors.
Conclusions/interpretation
The higher VAT-adjusted DI in white men than Japanese men may partly explain lower susceptibility of white people than Japanese people to developing type 2 diabetes. The results, however, should be interpreted with caution because the assessment of insulin indices was made using fasting samples and adjustment was not made for baseline glucose tolerance. Further studies using formal methods to evaluate insulin indices are warranted.
Carotid plaque has emerged as a marker of coronary heart disease (CHD) risk. Comparison of carotid plaque burden between different race/ethnic groups may provide a relative estimate of their future ...CHD risk.
We conducted a population-based study among apparently healthy middle-aged men aged 40–49 years (ERA JUMP study (n = 924)) and recruited 310 Whites in Pittsburgh, US, 313 Japanese in Otsu, Japan, and 301 Koreans in Ansan, South Korea. The number of carotid plaque and CHD risk factors was assessed using a standardized protocol across all centers. The burden of carotid plaque was compared between race/ethnic groups after adjustment for age and BMI, and after multivariable adjustment for other CHD risk factors using marginalized zero-inflated Poisson regression models. Cross-sectional associations of risk factors with plaque were examined.
Whites (22.8%) had more than four-fold higher prevalence (p < 0.01) of carotid plaque than Japanese men (4.8%) while the prevalence among Koreans was 10.6%. These differences remained significant after adjustment for age, BMI as well as other risk factors – incidence density ratio (95% confidence interval) for plaque was 0.13 (0.07, 0.24) for Japanese and 0.32 (0.18, 0.58) for Koreans as compared to Whites. Age, hypertension and diabetes were the only risk factors significantly associated with presence of carotid plaque in the overall population.
Whites have significantly higher carotid plaque burden than men in Japan and Korea. Lower carotid plaque burden among Japanese and Koreans is independent of traditional CVD risk factors.
•White men in the US have four-fold higher carotid plaque than Japanese and twice as much as Koreans.•These differences persist after accounting for lower BMI among east Asians in the study.•Overall, age, hypertension and diabetes status are associated with higher carotid plaque burden.
Abstract Background Brachial-ankle pulse wave velocity ( ba PWV) is a simple and reproducible measure of arterial stiffness and is extensively used to assess cardiovascular disease (CVD) risk in ...eastern Asia. We examined whether ba PWV is associated with coronary atherosclerosis in an international study of healthy middle-aged men. Methods A population-based sample of 1131 men aged 40–49 years was recruited — 257 Whites and 75 Blacks in Pittsburgh, US, 228 Japanese-Americans in Honolulu, US, 292 Japanese in Otsu, Japan, and 279 Koreans in Ansan, Korea. ba PWV was measured with an automated waveform analyzer (VP2000, Omron) and atherosclerosis was examined as coronary artery calcification (CAC) by computed-tomography (GE-Imatron EBT scanner). Association of the presence of CAC (defined as ≥ 10 Agatston unit) was examined with continuous measure as well as with increasing quartiles of ba PWV. Results As compared to the lowest quartile of ba PWV, the multivariable-adjusted odds ratio (95% Confidence Interval CI) for the presence of CAC in the combined sample was 1.70 (0.98, 2.94) for 2nd quartile, 1.88 (1.08, 3.28) for 3rd quartile, and 2.16 (1.19, 3.94) for 4th quartile (p-trend = 0.01). The odds for CAC increased by 19% per 100 cm/s increase (p < 0.01), or by 36% per standard-deviation increase (p < 0.01) in ba PWV. Similar effect-sizes were observed in individual races, and were significant among Whites, Blacks and Koreans. Conclusion ba PWV is cross-sectionally associated with CAC among healthy middle-aged men. The association was significant in Whites and Blacks in the US, and among Koreans. Longitudinal studies are needed to determine its CVD predictive ability.
T-helper type 1 (Th1) cells are pro-inflammatory and provide signals to immune cells. Animal models and in vitro human cell culture experiments have indicated that long chain n-3 polyunsaturated ...fatty acids (LCn3PUFAs) reduce Th1 cell levels; however, the association is unknown in healthy humans. We hypothesized that circulating levels and dietary intake of LCn3PUFAs have an inverse association with circulating levels of Th1 cells and studied 895 participants in the Multi-Ethnic Study of Atherosclerosis (age 61 ± 10 years at exam 1, 52% women, 44% white, 21% African-American, 24% Hispanic-American, 11% Chinese-American). Phospholipid LCn3PUFAs (% of total fatty acids), measured by gas chromatography, and intake of LCn3PUFAs, evaluated by food frequency questionnaire, were evaluated at exam 1 (2000-02) and defined as the sum of eicosapentaenoic and docosahexaenoic acids. Th1 cells were measured by flow cytometry at exam 4 (2005-07), expressed as a percentage of CD4+ lymphocytes that were interferon-γ+ (%Th1: CD4+IFN-γ+). Median (interquartile range) plasma LCn3PUFA, dietary LCn3PUFA, and %Th1 levels were 4.31% (3.40–5.82%), 0.09 (0.05–0.16) g/day, and 14.4% (9.8–20.0%), respectively. When the association of LCn3PUFA-quartiles with %Th1 was analyzed using general linear models, neither plasma nor dietary LCn3PUFAs were significantly associated with %Th1 (P-trend = 0.58 and 0.80, respectively), which remained even after adjusting for demographics, lifestyle factors, lipids, season, and cytomegalovirus titers. In this multi-ethnic U.S. population, circulating levels and dietary intake of LCn3PUFAs were not significantly associated with Th1 cell levels. Further research is needed to assess potential benefits of supplementation and much higher dietary consumption of LCn3PUFAs on Th1 cells.
•LCn3PUFAs are associated with lower Th1 cell levels in animal and in vitro studies.•The association of LCn3PUFAs and Th1 cell levels is unknown in healthy humans.•LCn3PUFas were not asociated with Th1 cell levels in our multi-ethnic U.S. cohort.•Null results were with both plasma and dietary intakes of LCn3PUFAs.•LCn3PUFA levels in our cohort may have been too low for immunomodulatory effects.
Abstract Background Progression of coronary artery calcium (CAC) is associated with increased risk of coronary heart disease (CHD) and is reported to be greater in whites than blacks, Hispanics, and ...Chinese in the US. Our objective was to compare progression of CAC between Japanese Americans and whites. Methods Population-based sample of 303 Japanese American men and 310 white men aged 40–49 years, free of clinical cardiovascular disease at baseline were examined for CAC at baseline (2002–07) and follow-up (2008–2013). Progression of CAC was defined as: change in coronary calcium scores (CCS) in participants with baseline CCS > 0 and incident CAC in participants with baseline CCS = 0. Multiple linear regression and relative risk regression were used to compare change in CCS scores and incident CAC between the two races, respectively. Results Japanese American men had significantly greater annual change in CCS than white men (median interquartile range: 11.3 Agatston units 1.4, 24.9 vs 2.5 − 0.22, 14.5) in the unadjusted analyses. After adjusting for cardiovascular risk factors and follow-up time, change in CCS (beta ± CI) and incidence rate ratio of CAC was similar in Japanese American men and white men: − 0.12 (− 0.34, 0.15) and (0.87 95% CI: 0.20, 3.9), respectively. Conclusions In contrast to previously reported greater progression of CAC in whites than other races, we found a similar progression of CAC in Japanese American men as white men. Our study identifies Japanese American men as a target group for prevention of CHD. Large prospective studies are warranted to confirm these findings.
This manuscript examines three separate but inter-related research questions. After reviewing scientifically relevant literature in the first chapter, the second chapter compares the prevalence of ...carotid plaque among the three major race-ethnic groups in the Electron-beam computed tomography, Risk factor Assessment among Japanese and U.S. Men in the Post-World War II birth cohort (ERA JUMP Study). This study shows that prevalence of carotid plaque, a biomarker of subclinical atherosclerosis, is significantly lower among men in Japan and South Korea than in the US. This difference is independent of traditional risk factors of coronary heart disease (CHD). Further, it shows that only age, hypertension and diabetes are cross-sectionally associated with the prevalence of carotid plaque. The third chapter examines the association between brachial-ankle pulse wave velocity (baPWV) and coronary artery calcification (CAC), an established biomarker of coronary atherosclerosis and a strong predictor of future CHD risk. baPWV is a non-invasive and convenient measure of arterial stiffness and is clinically used in eastern Asia as a tool for assessing future cardiovascular risk. This study found that higher baPWV is cross-sectionally associated with higher prevalence of CAC among middle-aged men in the ERA JUMP study, including White men in the US. The final and fourth chapter of the manuscript examines the association of serum levels of soy isoflavones and equol, with CAC among Japanese men in Japan. Japanese consume soy and soy products regularly. Isoflavones are a component in soy and are known to have anti-atherosclerotic properties. Equol is a potent isoflavone produced from the dietary isoflavone daidzein by action of intestinal bacteria. This study shows that individuals who have bacteria to convert daidzein to equol, i.e. equol producers, have lower CAC than equol non-producers. These three studies, individually and as a whole, contribute significantly to public health knowledge. Japan has significantly lower atherosclerosis than the US in spite of a similar level of risk factors. Several lessons, including change in diet, may be learned from Japan in an effort to reduce CHD mortality in the US. baPWV may potentially provide similar information to clinicians as CAC without exposing the patient to radiation.
ObjectiveThis cross-sectional study examined whether contrasting distributions of nuclear magnetic resonance (NMR)-measured lipoproteins contribute to differences in the prevalence of subclinical ...atherosclerosis measured using coronary artery calcium (CAC) between the two groups of middle-aged males: the US-residing Caucasian (US-White) and Japan-residing Japanese (Japanese).MethodsIn a population-based study of 570 randomly selected asymptomatic men aged 40–49 years (270 US-White and 300 Japanese), we examined the relationship between race/ethnicity, NMR-measured lipoproteins and CAC (measured by Electron Beam CT and quantified using the Agatston method) using multivariable robust Poisson regression adjusting for traditional and novel risk factors for coronary heart disease (CHD).ResultsThe US-White compared with the Japanese had significantly different NMR-measured lipoprotein particle distributions. The US-White had a significantly higher prevalence of CAC≥10 (CAC-prevalence) compared with the Japanese adjusting for CHD risk factors (prevalence ratio (PR)=2.10; 95% CI=1.24 to 3.48), and this difference was partially attenuated (~18%) with further adjustment for lipoprotein levels (PR=1.73; 95% CI=1.02 to 3.08). There was no reclassification improvement with further addition of lipoproteins particle concentrations/size to a model that already included traditionally measured lipids (low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglycerides), cardiovascular risk factors, and inflammatory markers (net reclassification improvement index=−2% to 3%).ConclusionsVariations in the distribution of NMR-measured lipoprotein particles partially accounted for the difference in the CAC-prevalence between middle-aged US-White and Japanese men.
At the same level of BMI, white people have less visceral adipose tissue (VAT) and are less susceptible to developing type 2 diabetes than Japanese people. No previous population-based studies have ...compared insulin resistance and insulin secretion between these two races in a standardised manner that accounts for VAT. We compared HOMA-IR, HOMA of beta cell function (HOMA-beta%) and disposition index (DI) in US white men and Japanese men in Japan. We conducted a population-based, cross-sectional study, comprising 298 white men and 294 Japanese men aged 40-49 years without diabetes. Insulin, glucose, VAT and other measurements were performed at the University of Pittsburgh. We used ANCOVA to compare geometric means of HOMA-IR, HOMA-beta% and DI, adjusting for VAT and other covariates. White men had higher HOMA-IR, HOMA-beta% and DI than Japanese men, and the difference remained significant (p<0.01) after adjusting for VAT (geometric mean 95% CI): 3.1 (2.9, 3.2) vs 2.5 (2.4, 2.6), 130.8 (124.6, 137.3) vs 86.7 (82.5, 91.0), and 42.4 (41.0, 44.0) vs 34.8 (33.6, 36.0), respectively. Moreover, HOMA-IR, HOMA-beta% and DI were significantly higher in white men even after further adjustment for BMI, impaired fasting glucose and other risk factors. The higher VAT-adjusted DI in white men than Japanese men may partly explain lower susceptibility of white people than Japanese people to developing type 2 diabetes. The results, however, should be interpreted with caution because the assessment of insulin indices was made using fasting samples and adjustment was not made for baseline glucose tolerance. Further studies using formal methods to evaluate insulin indices are warranted.PUBLICATION ABSTRACT
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