Cardiorespiratory fitness, exercise haemodynamics and birth outcomes: the Coronary Artery Risk Development in Young Adults Study.

OBJECTIVE: Determine associations of cardiorespiratory fitness, exercise systolic blood pressure (SBP) and heart rate recovery (HRR) following a maximal exercise test performed years preceding pregnancy with odds of preterm birth (PTB; <37 weeks' gestation) and small for gestational age (SGA; birthweight <10th percentile) delivery. DESIGN: Prospective, longitudinal. SETTING: Multi-site, observational cohort study initially consisting of 2787 black and white women aged 18-30 at baseline (1985-86) and followed for 25 years (Y25; 2010-2011). POPULATION: 768 nulliparous women at baseline who reported ≥1 live birth by the Y25 exam. METHODS: We used Poisson regression to determine associations of exposures with PTB/SGA. MAIN OUTCOME MEASURES: PTB and/or SGA births. RESULTS: Women with PTB (n = 143) and/or SGA (n = 88) were younger, had completed fewer years of education and were more likely to be black versus women without PTB/SGA (n = 546). Women with PTB/SGA had lower fitness (501 ± 9 versus 535 ± 6 seconds, P < 0.002) and higher submaximal SBP than women without PTB/SGA (144 ± 1 versus 142 ± 1 mmHg, P < 0.04). After adjustment, no exercise test variables were associated with PTB/SGA, though the association with HRR and submaximal SBP approached significance in the subset of women who completed the exercise test <5 years before the index birth. CONCLUSIONS: Neither fitness nor haemodynamic responses to exercise a median of 5 years preceding pregnancy, were associated with PTB/SGA. These findings indicate excess likelihood of PTB/SGA is not detectable by low fitness or exercise haemodynamic responses 5 years preceding pregnancy, but exercise testing, especially HRR and submaximal SBP, may be more useful when conducted closer to the onset of pregnancy. TWEETABLE ABSTRACT: Exercise testing conducted >5 years before pregnancy may not detect women likely to have PTB/SGA.

Generalization and fine mapping of European ancestry-based central adiposity variants in African ancestry populations.

BACKGROUND/OBJECTIVES: Central adiposity measures such as waist circumference (WC) and waist-to-hip ratio (WHR) are associated with cardiometabolic disorders independently of body mass index (BMI) and are gaining clinically utility. Several studies report genetic variants associated with central adiposity, but most utilize only European ancestry populations. Understanding whether the genetic associations discovered among mainly European descendants are shared with African ancestry populations will help elucidate the biological underpinnings of abdominal fat deposition. SUBJECTS/METHODS: To identify the underlying functional genetic determinants of body fat distribution, we conducted an array-wide association meta-analysis among persons of African ancestry across seven studies/consortia participating in the Population Architecture using Genomics and Epidemiology (PAGE) consortium. We used the Metabochip array, designed for fine-mapping cardiovascular-associated loci, to explore novel array-wide associations with WC and WHR among 15 945 African descendants using all and sex-stratified groups. We further interrogated 17 known WHR regions for African ancestry-specific variants. RESULTS: Of the 17 WHR loci, eight single-nucleotide polymorphisms (SNPs) located in four loci were replicated in the sex-combined or sex-stratified meta-analyses. Two of these eight independently associated with WHR after conditioning on the known variant in European descendants (rs12096179 in TBX15-WARS2 and rs2059092 in ADAMTS9). In the fine-mapping assessment, the putative functional region was reduced across all four loci but to varying degrees (average 40% drop in number of putative SNPs and 20% drop in genomic region). Similar to previous studies, the significant SNPs in the female-stratified analysis were stronger than the significant SNPs from the sex-combined analysis. No novel associations were detected in the array-wide analyses. CONCLUSIONS: Of 17 previously identified loci, four loci replicated in the African ancestry populations of this study. Utilizing different linkage disequilibrium patterns observed between European and African ancestries, we narrowed the suggestive region containing causative variants for all four loci.

Risk factors for exposure to influenza a viruses, including subtype H5 viruses, in Thai free-grazing ducks.

Free-grazing ducks (FGD) have been associated with highly pathogenic avian influenza (HPAI) H5N1 outbreaks and may be a viral reservoir. In July-August 2010, we assessed influenza exposure of Thai FGD and risk factors thereof. Serum from 6254 ducks was analysed with enzyme-linked immunosorbent assay (ELISA) to detect antibodies to influenza A nucleoprotein (NP), and haemagglutinin H5 protein. Eighty-five per cent (5305 ducks) were seropositive for influenza A. Of the NP-seropositive sera tested with H5 assays (n = 1423), 553 (39%) were H5 ELISA positive and 57 (4%) suspect. Twelve per cent (74 of 610) of H5 ELISA-positive/suspect ducks had H5 titres ≥ 1 : 20 by haemagglutination inhibition. Risk factors for influenza A seropositivity include older age, poultry contact, flock visitors and older purchase age. Study flocks had H5 virus exposure as recently as March 2010, but no HPAI H5N1 outbreaks have been identified in Thailand since 2008, highlighting a need for rigorous FGD surveillance.

Prospective association of serum androgens and sex hormone-binding globulin with subclinical cardiovascular disease in young adult women: the "Coronary Artery Risk Development in Young Adults" women's study.

CONTEXT: The role of endogenous androgens and SHBG in the development of cardiovascular disease in young adult women is unclear. OBJECTIVE: Our objective was to study the prospective association of serum androgens and SHBG with subclinical coronary and carotid disease among young to middle-aged women. DESIGN AND SETTING: This was an ancillary study to the Coronary Artery Risk Development in Young Adults (CARDIA) study, a population-based multicenter cohort study with 20 yr of follow-up. PARTICIPANTS: Participants included 1629 women with measurements of serum testosterone and SHBG from yr 2, 10, or 16 and subclinical disease assessment at yr 20 (ages 37-52 yr). MAIN OUTCOME MEASURES: Coronary artery calcified plaques (CAC) and carotid artery intima-media thickness (IMT) were assessed at yr 20. The IMT measure incorporated the common carotid arteries, bifurcations, and internal carotid arteries. RESULTS: SHBG (mean of yr 2, 10, and 16) was inversely associated with the presence of CAC (multivariable adjusted odds ratio for women with SHBG levels above the median = 0.59; 95% confidence interval = 0.40-0.87; P = 0.008). SHBG was also inversely associated with the highest quartile of carotid-IMT (odds ratio for women with SHBG levels in the highest quartile = 0.56; 95% confidence interval = 0.37-0.84; P for linear trend across quartiles = 0.005). No associations were observed for total or free testosterone with either CAC or IMT. CONCLUSION: SHBG levels were inversely associated with subclinical cardiovascular disease in young to middle-aged women. The extent to which low SHBG is a risk marker or has its own independent effects on atherosclerosis is yet to be determined.

Changes in risk factors for cardiovascular disease by baseline weight status in young adults who maintain or gain weight over 15 years: the CARDIA study.

OBJECTIVES: To examine whether changes in cardiovascular disease (CVD) risk factors differ by baseline weight status among young adults who maintained or gained weight. DESIGN: Longitudinal cohort study. SUBJECTS: White and African Americans who either maintained (+/-5 pounds; n=488) or gained (>5 pounds; n=2788) weight over 15 years. MEASUREMENTS: Anthropometrics and CVD risk factors were measured at baseline (1985-1986) and follow-up. Participants were classified as normal weight (body mass index (BMI) 18.5-24.9 kg/m2) or overweight (BMI >or=25 kg/m2) at baseline. Multivariable models were stratified by ethnicity and weight change category. RESULTS: Normal weight maintainers tended to have more favorable risk factors at baseline and follow-up than overweight maintainers. Size and direction of 15-year changes in risk factors were similar by weight status, except that in white normal weight maintainers changes in high-density lipoprotein (HDL)-cholesterol (3.3 mg/dl (95% confidence interval (CI): 0.4, 6.3)) and triglycerides (-14.7 mg/dl (-25.8, -3.7)) were more favorable. Weight gain was associated with unfavorable changes in risk factors. Weight gainers normal weight at baseline had less adverse changes in glucose, blood pressure, HDL-cholesterol (whites only) and triglycerides (African Americans only) than overweight gainers. However, normal weight African-American weight gainers had more adverse changes in total (3.1 mg/dl (0.2, 6.1)) and low-density lipoprotein-cholesterol (3.4 mg/dl (0.6, 6.3)). CONCLUSIONS: Baseline weight status does not appear to influence the size or direction of risk factor changes among adults who maintained their weight over 15 years. In contrast, weight gain was associated with changes in some risk factors differentially by baseline weight status.

Dietary intake of n-3, n-6 fatty acids and fish: relationship with hostility in young adults--the CARDIA study.

BACKGROUND: Hostility has been shown to predict both the development and manifestation of coronary disease. Examining the inter-relation of dietary intake of fish and of polyunsaturated (n-3 and n-6) essential fatty acids with hostility may provide additional insights into the cardioprotective effect of dietary fish and polyunsaturated fatty acids. OBJECTIVE: To examine the association of dietary n-3, n-6 fatty acids and fish with level of hostility in a sample of 3581 urban white and black young adults. DESIGN: Cross-sectional observational study as part of an ongoing cohort study. A dietary assessment in 1992-1993 and measurement of hostility and other covariates in 1990-1991 were used in the analysis. RESULTS: The multivariate odds ratios of scoring in the upper quartile of hostility (adjusting for age, sex, race, field center, educational attainment, marital status, body mass index, smoking, alcohol consumption and physical activity) associated with one standard deviation increase in docosahexaenoic acid (DHA, 22:6) intake was 0.90 (95% CI=0.82-0.98; P=0.02). Consumption of any fish rich in n-3 fatty acids, compared to no consumption, was also independently associated with lower odds of high hostility (OR=0.82; 95% CI=0.69-0.97; P=0.02). CONCLUSIONS: These results suggest that high dietary intake of DHA and consumption of fish rich in n-3 fatty acids may be related to lower likelihood of high hostility in young adulthood. The association between dietary n-3 fatty acids and hostile personality merits further research.

Disability after clinical fracture in postmenopausal women with low bone density: the fracture intervention trial (FIT).

Relatively little is known about outcomes following clinical osteoporotic fractures at nonhip, nonvertebral skeletal sites. To address this issue, we prospectively assessed post-fracture disability at multiple skeletal sites in a population of 909 older (aged 55-81 years), community-dwelling women with low femoral neck bone mineral density who had experienced a fracture while enrolled in the Fracture Intervention Trial (FIT). FIT is a randomized, double-masked, placebo-controlled trial that was designed to determine the effect of alendronate on fracture incidence, and the current study was conducted as a secondary analysis of FIT data. Following incident clinical fractures, FIT participants were followed prospectively for assessment of site-specific, fracture-related disability. Measures of disability were self-reported days hospitalized or confined to bed because of the fracture ('bed days') and days of reduced usual activities because of the fracture ('limited activity days'). Of fracture types evaluated, those of the hip resulted in the highest percentage of subjects with any bed days or limited activity days after fracture (94% with any bed days and 100% with any limited activity days), though the mean number of bed days and limited activity days appeared highest after lumbar vertebral fractures (25.8 mean bed days and 158.5 mean limited activity days). Substantial disability also was reported after fractures of thoracic vertebrae, humerus, distal forearm, ankle and foot. Within fracture types, post-fracture disability was highly variable, ranging from none to more than 6 months.

Gender differences in recurrent coronary events; the FINMONICA MI register.

BACKGROUND: Male gender is an established risk factor for first myocardial infarction, but some studies have suggested that among myocardial infarction survivors, women fare worse than men. Therefore, we examined the long-term prognosis of incident myocardial infarction survivors in a large, population-based MI register, addressing gender differences in mortality as well as the number of events and time intervals between recurrent events. METHODS AND RESULTS: Study subjects included 4900 men and women, aged 25-64 years, with definite or probable first myocardial infarctions who were alive 28 days after the onset of symptoms. At first myocardial infarction, women were older and more likely to be hypertensive or diabetic than men, and had a greater proportion of probable vs definite events. After adjustment for age and geographic region, men had 1.74 times the risk of fatal coronary heart disease relative to women (hazard ratio=1.63 and 1.55 for cardiovascular disease and all-cause mortality, respectively) over an average of 5.9 years of follow-up. Number and time intervals between any recurrent event--fatal and non-fatal--did not differ by gender. CONCLUSION: These data suggest that men are far more likely to have a fatal recurrent event than women despite comparable numbers of events.

Older women with diabetes have an increased risk of fracture: a prospective study.

To determine whether type 2 diabetes is associated with fracture in older women, we analyzed data from 9654 women, age 65 yr or older, in the Study of Osteoporotic Fractures. Diabetes with age at onset 40 yr or older was reported by 657 women, of whom 106 used insulin. A total of 2624 women experienced at least one nonvertebral fracture during an average follow-up of 9.4 yr, and 388 had at least one vertebral fracture during an average interval of 3.7 yr. Although diabetes was associated with higher bone mineral density, it was also associated with a higher risk of specific fractures. Compared with nondiabetics, women with diabetes who were not using insulin had an increased risk of hip [relative risk (RR), 1.82; 95% confidence interval (CI), 1.24-2.69] and proximal humerus (RR, 1.94; 95% CI, 1.24-3.02) fractures in multivariate models controlling for age, body mass index, bone density, and other factors associated with fractures and diabetes. Insulin-treated diabetics had more than double the risk of foot (multivariate adjusted RR, 2.66; 95% CI, 1.18-6.02) fractures compared with nondiabetics. This study indicates that diabetes is a risk factor for hip, proximal humerus, and foot fractures among older women, suggesting that fracture prevention efforts should be a consideration in the treatment of diabetes.

Independent and interactive effects of apolipoprotein E phenotype and cardiorespiratory fitness on plasma lipids.

PURPOSE: To examine whether the association Apolipoprotein E (Apo E) phenotype with plasma lipids is influenced by physical fitness level. Also, to explore the interactive and independent relative contributions of Apo E phenotype, fitness (or physical activity), and other modifiable factors to variation in plasma low density lipoprotein (LDL-C) and high density lipoprotein (HDL-C) levels at baseline and over a seven-year follow-up. METHODS: Physical fitness (duration of a graded treadmill test), Apo E phenotype, plasma LDL-C and HDL-C, and covariates were measured at baseline and seven years later in a bi-racial cohort of young adults, aged 18-30 years at baseline in 1985-86, from the Coronary Artery Risk Development In Young Adults (CARDIA) study. RESULTS: Fitness did not influence the associations of Apo E and LDL-C or HDL-C. The independent effects of several modifiable variables (changes in Keys' score, smoking, oral contraceptive use, education, body weight, alcohol intake, and fitness), when combined, contributed considerably more than Apo E to the variance in LDL-C changes (6.74% or 8.71% for combined modifiable variables vs. 1.27% or 0.90% for ApoE, in women or men, respectively) and HDL-C changes (13.11% or 12.66% for combined modifiable variables vs. 0.12% or 0.02% for ApoE, in women or men, respectively). The pattern of findings was similar when self-reported physical activity was substituted for fitness. CONCLUSIONS: Changes in modifiable factors, including fitness, may be stronger correlates of changes in LDL-C and HDL-C over time than the immutable factor, Apo E phenotype.

Association of ventricular premature complexes with electrocardiographic-estimated left ventricular mass in a population of African-American and white men and women (The Atherosclerosis Risk in Communities.

Increased left ventricular (LV) mass is often found in adults and is a powerful predictor of cardiovascular mortality. To test the hypothesis that an electrocardiographic estimate of LV mass--the Cornell voltage--is associated with ventricular premature complexes (VPCs) in free-living adults, a cross-sectional analysis of the predictors of VPCs on a 2-minute rhythm strip in a population-based sample of 13,606 middle-aged, African-American and white men and women from 4 US communities in the Atherosclerosis Risk in Communities Study baseline examinations was performed. In adults without known coronary artery disease, the prevalence of VPCs increases monotonically with increasd Cornell voltages within ethnicity and gender groups. Independent of systemic hypertension, serum electrolytes, age, heart rate, educational attainment, gender, and ethnicity, a millivolt increase in Cornell voltage was associated with a 20% to 30% increase in the prevalence odds ratio of VPCs on the 2-minute electrocardiogram. Thus, Cornell voltage is associated with VPCs on a 2-minute electrocardiogram. The association is consistent in African-Americans, whites, men, and women.

Changes in US health care access in the 90s: race and income differences from the CARDIA Study. Coronary Artery Risk Development in Young Adults.

OBJECTIVE: Health care financing is changing rapidly in the United States. We investigated whether and how health care access is changing concurrently with changes in financing, with special attention to a minority population. METHODS: We examined a longitudinal biracial (half African-American, half White) urban cohort of 3,565 individuals, aged 25-37 years old, in 1992-93 and again in 1995-96. We measured access by self-reported (1) health insurance status, (2) regular source of medical care, and (3) lack of care due to financial problems. RESULTS: In 1992-93, 30.3% of the cohort experienced at least one access barrier, with a decline to 26.8% in 1995-96 (P<.005). However, access improved more for Whites than for African Americans; and access improved for higher, but not for lower, income groups (7% improvement for high income, vs 2% deterioration for lower income, P<.01). In addition, there was an 11% to 19% absolute increase in individuals making co-payments for health care utilization across all race/sex groups, with African Americans having markedly higher proportions of cost-sharing. African-American, low income, and unemployed individuals reported more acute care, but fewer outpatient visits. Income and employment explained racial differences. CONCLUSION: While access has improved or stabilized for higher income groups, there is a widening gap according to income, accompanied by an acute care pattern for low income groups that may be both inadequate and cost inefficient.

The Family Risk Score for coronary heart disease: associations with lipids, lipoproteins, and body habitus in a middle-aged bi-racial cohort: The ARIC study.

PURPOSE: To examine the association between the Family Risk Score (FRS) for coronary heart disease (CHD) and body mass index (BMI), waist-to-hip ratio (WHR), high density lipoprotein (HDL) and low density lipoprotein (LDL) cholesterol, triglycerides, and lipoprotein(a) protein [Lp(a)]. METHODS: FRS was computed from observed and expected CHD events using family data collected from 11467 black and white adults of the Atherosclerosis Risk in Communities Study (ARIC). BMI, WHR, and lipids adjusted for study center, race, education, BMI (except BMI), WHR (except for BMI and WHR), cigarette smoking, alcohol, and Keys' score were compared among low (FRS < -0.5), average (-0.5 to 0.5), and high (> 0.5) FRS using analysis of covariance. The association between FRS and these risk factors was compared to that for simpler estimates of family risk. RESULTS: Adjusted means of BMI, WHR, LDL, LP(a), and triglycerides were positively associated with FRS, whereas HDL cholesterol was inversely associated with FRS. Of demographic and behavioral factors, cigarette smoking was most strongly associated with FRS. Based on additional comparisons of adjusted means, high vs. low levels of FRS appear to correlate better with CHD risk factors than do the simpler family history assessments. CONCLUSIONS: In situations were genetic or clinical information is not available, FRS may be a favorable measure of familial burden for CHD.

Weight gain continues in the 1990s: 10-year trends in weight and overweight from the CARDIA study. Coronary Artery Risk Development in Young Adults.

The prevalence of obesity increased in the United States through the 1980s. The authors examined 10-year aging and secular (time-related) trends in the Coronary Artery Risk Development in Young Adults (CARDIA) cohort for indications of whether these trends are continuing and for ages of peak weight gain in young adults. CARDIA is a population-based, prospective study of 5,115 African-American and White men and women aged 18-30 years at baseline. Body weight and overweight prevalence were measured at five time points from 1985-1986 to 1995-1996. Linear, mixed-model regression was used to partition weight gain into that due to secular trends and that due to aging. Prevalence of overweight (body mass index (BMI) > or = 25.0 kg/m2) increased markedly, and prevalence of severe obesity (BMI > or = 40.0 kg/m2) doubled in all race-sex groups. Each race-sex group experienced significant secular weight gains, ranging from 0.96 kg/year (95% confidence interval: 79, 1.13) in African-American women to 0.55 kg/year (95% confidence interval: 0.41, 0.69) in White women. Significant secular gains were present during each follow-up period. Each race-sex group also experienced significant weight increases related to aging during their early to midtwenties. Secular trends for weight gain are continuing in CARDIA, but the magnitude of weight gain differed among the four race-sex groups.

Body size and risk for clinical fractures in older women. Study of Osteoporotic Fractures Research Group.

BACKGROUND: Small body size predicts hip fractures in older women. OBJECTIVE: To test the hypothesis that small body size predicts the risk for other clinical fractures. DESIGN: Prospective cohort study. SETTING: Population-based listings in four areas of the United States. PATIENTS: 8059 ambulatory nonblack women 65 years of age or older. MEASUREMENTS: Weight, weight change since 25 years of age, body mass index, lean body mass and percent body fat, and nonspine fractures during 6.4 years of follow-up. RESULTS: Compared with women in the highest quartile of weight, women in the lowest quartile had relative risks of 2.0 (95% CI, 1.5 to 2.8) for hip fractures, 2.3 (CI, 1.1 to 4.7) for pelvis fractures, and 2.4 (CI, 1.5 to 3.9) for rib fractures. Adjustment for total-hip bone mineral density eliminated the elevated risk. Results were similar for other body size measures. Smaller body size was not a risk factor for humerus, elbow, wrist ankle, or foot fractures. CONCLUSIONS: Total body weight is useful in the prediction of hip, pelvis, and rib fractures when bone mineral density has not been measured.

Physical activity and body weight: associations over ten years in the CARDIA study. Coronary Artery Risk Development in Young Adults.

BACKGROUND: Hypothesis 1--sustained changes in physical activity are inversely related to changes in body weight. Hypothesis 2-those who attenuate weight gain because of a temporary increase in physical activity (PA) may maintain a lower body weight over time. METHODS: Data were from the Coronary Artery Risk Development in Young Adults (CARDIA) Study, a cohort of black and white men and women, aged 18-30y at baseline, who attended up to five examinations over a 10y period (n=5,115 at baseline). Longitudinal associations between physical activity and body weight changes were assessed, adjusting for secular trend, age, clinic site, education, smoking, alcohol intake, parity, percentage energy intake from fat, and changes in these variables over time. For hypothesis 1, concurrent associations of physical activity and body weight changes were examined. For hypothesis 2, we explored whether weight gain attenuation associated with increased PA during the initial 2-3 y of follow-up was sustained over 5 y. The study 2 analyses were conducted with three separate 5y intervals: baseline to year 5 (n= 3,641), years 2-7 (n= 3,160), and years 5-10 (n= 2,617). RESULTS: Hypothesis 1 -change in physical activity was inversely associated with change in body weight within all four race and sex sub-groups (P<0.005). The predicted weight change associated with change in physical activity was four to five times larger in participants who were overweight compared with those who were not were overweight at baseline. Hypothesis 2-an increase in physical activity during 2-3 y of follow-up was associated with an attenuation of weight gain that was sustained through 5y of follow-up whether or not the physical activity increase was maintained during the later years. This finding persisted whether the starting point for the 5y follow-up was year 2, year 5 or baseline (women only). Comparing participants who increased physical activity with those who decreased physical activity in the first 2-3 y of follow-up (eg by at least 2 h per week of stationary cycling for at least 6 months per year), the mean 5y weight gain attenuation ranged from 0.8 to 2.8 kg. CONCLUSIONS: The results of these analyses support the need for public health messages for promoting increased physical activity for weight maintenance and attenuation of age-related weight gain, especially for higher weight sub-populations.

The relationship between lipids/lipoproteins and atherosclerosis in African Americans and whites: the Atherosclerosis Risk in Communities Study.

PURPOSE: The relationships between lipids/lipoproteins and atherosclerosis were determined in African Americans and whites to assess the consistency of the relationship between these two groups. Differences could suggest varying biological, environmental, or life-style cofactors influencing development of atherosclerosis. METHODS: In the Atherosclerosis Risk in Communities Study, 2966 African Americans and 9399 whites had determinations of LDL, HDL, HDL2, and HDL3 cholesterol, triglycerides, apolipoprotein A1 and B, and lipoprotein (a). Carotid intimal-medial thickening (IMT) was measured using B-mode ultrasound imaging. RESULTS: The associations, using linear regression, between carotid IMT and LDL cholesterol, HDL cholesterol, and other lipid measurements were significantly weaker in African Americans than whites. Averaging men and women, a 1.034 mmol/L (40 mg/dl) difference in LDL cholesterol was associated with a 0.028 mm IMT difference in whites but a 0.019 difference in African Americans. Similarly, for HDL cholesterol, a 0.44 mmol/L (17 mg/dl) difference is associated wth 0.026 mm difference in carotid IMT in whites and 0.011 mm difference in African Americans. The associations are much weaker in African Americans than whites at the bifurcation and internal carotid, the carotid sites most prone to atherosclerosis. Analysis was done stratifying for risk factors that differ between African Americans and whites, but within most, the relationships remained substantially weaker in African Americans. CONCLUSIONS: We have observed a statistically significant difference in the association between many lipids/lipoproteins and carotid IMT between African Americans and whites. Analysis of many potential cofactors have not provided an explanation for the weaker association. Although possible differences in prior levels of these lipids may provide one explanation for the finding, these results need confirmation in other studies.

Serum leptin and weight gain over 8 years in African American and Caucasian young adults.

OBJECTIVE: There is considerable interest in how to prevent weight gain in adulthood. Leptin, a peptide hormone expressed in adipose tissue, is believed to signal the central nervous system about the level of body fat stores, and thereby may control appetite. Little information exists on whether the serum leptin concentration influences long-term weight changes in the free-living population. RESEARCH METHODS AND PROCEDURES: From an ongoing cohort study of young African American and white adults, we selected a sample of participants (n=492), stratified on sex, race, and weight changes over 8 years. Serum leptin was measured on stored specimens using a radioimmunoassay. Weight change was modeled in relation to baseline leptin concentrations. RESULTS: Cross-sectionally, leptin concentration was associated positively with body mass index, negatively with physical activity level, and was higher in women than men. These variables explained 72% of the variance in serum leptin. Over the 8 years, the sample gained an average of 7.8 kg (standard deviation = 10.8). There was no evidence that 8-year weight change was associated with initial leptin concentration: 8-year weight change was only 0.5 kg less (95% confidence interval =-1.8 to 0.8, p = 0.47) per each 10 ng/ mL increment (approximately one standard deviation) of baseline leptin. In contrast, leptin change correlated highly (r=0.62) with weight change. DISCUSSION: Our data corroborate evidence that adiposity determines leptin levels but do not support the hypothesis that leptin deficiency plays an important role in obesity in the general population.

Seven-year changes in physical fitness, physical activity, and lipid profile in the CARDIA study. Coronary Artery Risk Development in Young Adults.

PURPOSE: To relate seven year changes in physical fitness and physical activity in the young adult population to changes in the plasma lipid profile and to examine the influence of weight change on those relationships. METHODS: The participants in this observational study were the 1777 black and white men and women, ages 18-30 at entry into the Coronary Artery Risk Development in Young Adults (CARDIA) cohort, who completed a symptom-limited graded treadmill exercise test and had an overnight fasting blood draw at both the Baseline (1985-86) and Year 7 (1992-93) exams. CARDIA, a longitudinal study of the relationships of lifestyle and physiological variables to the development of coronary heart disease risk factors, consists of population-based cohorts in Birmingham, Alabama, Minneapolis, Minnesota and Chicago, Illinois and a cohort recruited from the membership of a large, pre-paid health care plan, broadly representative of the population, in Oakland, California. RESULTS: All race/gender groups experienced mean decreases in physical fitness and self-reported physical activity and increases in weight. Decreased fitness was associated with decreased high density lipoprotein-cholesterol (HDL-C), and conversely, increased fitness was associated with increased HDL-C. The correlation coefficients of change in fitness with change in HDL-C ranged from 0.17 in white men and black women to 0.24 in white women (P < 0.001 for all race/gender groups). Change in fitness was minimally correlated with change in low density lipoprotein-cholesterol (LDL-C) in all groups (r ranged from -0.09 in black women to -0.20 in white women), triglycerides (TG) in men and white women (r ranged from -0.10 to -0.15), and total cholesterol (TC) in white men and women (r = -0.11 and -0.15, respectively). The magnitude of these correlations was further reduced with adjustment for weight change. Correlations between change in activity and change in lipid and lipoprotein values were generally weak or nonexistent, except for the suggestion of a small, direct relationship with change in HDL-C in black and white women (r = 0.14 and r = 0.11, respectively). All of the weight change adjusted correlations were essentially unaffected by further adjustment for baseline fitness or activity and other covariates. CONCLUSIONS: Decreased fitness during young adulthood is associated with unfavorable changes in lipid profile, explained mostly by increased weight. Lack of association between change in activity and change in lipid profile observed in this study may be due, in part, to imprecision of activity measurement.

Body mass index, waist/hip ratio, and coronary heart disease incidence in African Americans and whites. Atherosclerosis Risk in Communities Study Investigators.

To study the relation of the amount and distribution of body fat with incident coronary heart disease in two ethnic groups, the authors analyzed prospective data from the Atherosclerosis Risk in Communities Study. Among 14,040 participants aged 45-64 years and free of coronary disease at baseline in 1987-1989, we identified 398 events through 1994, an average of 6.2 years of follow-up. Among African-American women, the multivariable-adjusted relative risks of coronary heart disease across quartiles of body mass index were 1.0, 1.91. 1.54, and 2.15 (p for trend=0.27), and those for waist/hip ratio were 1.0, 2.07, 2.33, and 4.22 (p for trend=0.02). Among African-American men, these respective relative risks were 1.0, 1.03, 0.83, and 1.20 (p for trend=0.76) for body mass index and 1.0, 1.08, 1.87, and 1.68 (p for trend=0.06) for waist/hip ratio. Relative risks for whites were generally similar to those for African Americans. Relative risks were stronger for never smokers than for the overall cohort. Unlike some previous studies, our results suggest that Africa Americans, like whites, are not spared from the coronary heart disease risks accompanying obesity.