Leisure-time physical activity, television watching, and plasma biomarkers of obesity and cardiovascular disease risk

The benefits of physical activity in reducing cardiovascular disease (CVD) are thought to be mediated through changes in blood lipids, insulin sensitivity, and thrombogenic factors. Few studies have addressed the effects of both long-term physical activity and inactivity on these factors. The authors assessed associations between long-term leisure-time physical activity, television watching, and biomarkers of CVD risk among 468 healthy male health professionals. Prior to blood collection in 1993-1994, physical activity and television watching were assessed biennially from 1986 to 1994 by a questionnaire. Physical activity was expressed as metabolic equivalents-hours per week. Multivariate linear regression analyses showed that metabolic equivalents-hours in 1994 were significantly associated with high density lipoprotein cholesterol (HDL cholesterol) (positively) and with leptin and C-peptide (inversely). The average number of hours of television watching assessed in 1994 was significantly positively associated with low density lipoprotein cholesterol and significantly inversely associated with HDL cholesterol and apolipoprotein A1. Average hours of television watching per week assessed in 1988-1994 was positively associated with leptin levels (p < 0.01). The associations of television watching and vigorous activity with leptin and HDL cholesterol were independent of each other. In conclusion, physical activity and television watching were significantly associated with several biochemical markers of obesity and CVD risk.     

Diet,Physical Activity,and Cardiovascular Disease Risk Factors Among Older Chinese Americans Living in New York City

Cardiovascular disease (CVD) is the leading cause of death in the US and affects Chinese Americans disproportionately compared to other ethnic groups in the American population. However, few studies have examined CVD risk factors, including diet and physical activity, in Chinese Americans. This investigation used a cross-sectional design to evaluate the dietary intake, dietary supplement use, and physical activity of 125 older Chinese Americans aged 50–98 years, and to determine how these behaviors may be related to obesity and other CVD risk factors. Sociodemographic information, CVD risk factors, dietary intake, and physical activity were obtained from all participants recruited from health fairs conducted in New York City (NYC). The findings revealed that older Chinese American adults living in NYC had a high prevalence of overweight and obesity, borderline hypertension, pre-diabetes, and diabetes. Many participants did not meet their daily requirements calcium, potassium, folate, vitamin B6, and vitamin B12, several minerals and vitamins important for cardiovascular health. Although most participants consumed an adequate numbers of servings of foods from the main food groups, most did not meet the recommended number of servings of dairy foods and only one in four adults took a multivitamin supplement daily. After adjusting for potential confounders, daily consumption of oil/sweets and dairy foods was positively associated with waist circumference. Also, daily consumption of oils/sweets, meats, and grains was positively associated with systolic blood pressure. The majority of the participants reported at least 30 min of moderate intensity physical activity per day. Dietary intake or supplement use did not show protective effects but performing vigorous physical activity may reduce risk of CVD in this population.     

社区高血压病人体质指数相关因素分析

目的了解社区高血压患者体质指数（BMI）和其他心脑血管疾病的危险因素的分布特点、冠心病发病风险、及它们间的相关情况。方法通过全人群现场调查和血压测量发现疑似病例，2w后对疑似病例复查来确诊高血压患者，对高血压患者进行详细的体检和血液的化验检查。对2015例确诊的社区高血压患者的资料进行统计分析。结果高血压患者中男性、女性的超重或肥胖患病率分别为57．2％、55．4％，远高于一般人群的患病率；BMI与甘油三酯（TG）、总胆固醇（TC）与高密度脂蛋白胆固醇（HDL—C）比值、低密度脂蛋白胆固醇（LDL—C）与高密度脂蛋白胆固醇（HDL-C）比值、TG／HDL—C、血糖的水平呈正相关，与HDL—C水平呈负相关；BMI与未来10a冠心病的预测发病风险呈正相关；超重或肥胖患者中危险因素水平、异常率高于正常体重组。结论高血压患者伴发超重或肥胖时，心脑血管病的发病风险增加，为了预防和控制心脑血管疾病的发生，应及早控制并减轻体重。     

The Contribution of Baseline Weight and Weight Gain to Blood Pressure Change in African Americans: The Pitt County Study

PURPOSE: The positive association between obesity and blood pressure has been less consistent in African Americans than whites. This is especially true for African American men. This study investigated the sex-specific associations between baseline body mass index (BMI), weight change (kilograms), and five-year hypertension incidence and changes in blood pressure in a cohort of African Americans ages 25–50 years at baseline.

METHODS: The Pitt County Study is a longitudinal investigation of anthropometric, psychosocial, and behavioral predictors of hypertension in African Americans. Data were obtained through household interviews and physical examinations in 1988 and 1993.

RESULTS: Baseline BMI was positively and independently associated with changes in blood pressure after controlling for weight change and other covariates. When participants were stratified by sex-specific overweight vs. nonoverweight status at baseline, weight gain was significantly associated with increases in blood pressure only among the initially nonoverweight.

CONCLUSIONS: Baseline weight for all respondents, and weight gain among the nonoverweight at baseline, were independent predictors of blood pressure increases in this cohort of African Americans.     

The relation between serum insulin levels and 8-year changes in lipid, lipoprotein, and blood pressure levels.

Hyperinsulinemia is associated with an adverse pattern of cardiovascular risk factors, including obesity, elevated triglyceride levels, low levels of high-density lipoprotein (HDL) cholesterol, and elevated blood pressure. Whether hyperinsulinemia precedes (and perhaps causes) this deterioration in the risk factors or merely accompanies the deterioration is controversial. We therefore examined the 8-year changes in lipids, lipoproteins, and blood pressure as a function of baseline levels of fasting insulin in 1,383 nondiabetic Mexican-American and non-Hispanic white subjects enrolled between October 1979 and November 1982 in the San Antonio Heart Study, a population-based longitudinal study of cardiovascular risk factors and diabetes in San Antonio, Texas. After age and concomitant changes in body mass index were adjusted for, fasting insulin at baseline was found to be correlated positively with 8-year changes in triglyceride levels and negatively with 8-year changes in HDL cholesterol levels (p less than 0.05). Among the non-Hispanic whites, insulin was more strongly correlated with a decline in HDL cholesterol levels in women than in men (p less than 0.001). Fasting insulin was also positively correlated with changes in both systolic and diastolic blood pressure in non-Hispanic whites, but not in Mexican Americans, although these correlations were slightly diminished and no longer achieved statistical significance after subjects receiving antihypertensive medications were excluded. These results support the hypothesis that in nondiabetic subjects, insulin has a direct regulatory effect on triglyceride and HDL cholesterol levels. These data provide evidence for a possible role for insulin in blood pressure regulation, at least in non-Hispanic whites, although further analysis of this issue is warranted.     

Cardiovascular risk factors in young,overweight, and obese European adults and associations with physical activity and omega-3 index

Excess body fat is associated with increased cardiovascular disease (CVD) risk. The hypothesis of the study was that physical activity and omega-3 index, a marker of past long chain n-3 polyunsaturated fatty acids consumption, counteract the negative associations between fatness and CVD risk factors in young overweight and obese adults. A total of 324 subjects (20-40 years, body mass index [BMI], 27.5-32.5 kg/m², from Iceland, Spain, and Ireland) were investigated cross-sectionally. Dietary intake, anthropometric measurements, blood pressure, CVD risk factors, and fatty acids in erythrocyte membrane were analyzed. Information on physical activity was collected. Linear models were constructed to find out the associations of BMI, physical activity (quartiles), and omega-3 index with CVD risk factors. The most frequently increased risk factors were blood lipids (41.4%) and blood pressure (32.1%); fewer participants experienced disturbed glucose metabolism (11.8%). Body mass index was significantly associated with increased CVD risk factors (P = .001-.029), with the exception of total cholesterol, low-density lipoprotein, and high-density lipoprotein. The highest physical activity quartile had a lower fat mass (P = .005, at a given BMI), leptin (P = .008, in male participants only), and interleukin 6 (P = .021) but higher high-density lipoprotein (P = .020) than other quartiles; however, an approximate dose-response relationship could only be observed for leptin. The omega-3 index was not associated with lower low-density lipoprotein (P = .056), but docosahexaenoic acid in erythrocyte membrane was associated to it (P = .016). It is concluded that physical activity and docosahexaenoic acid diminish some of the negative health effects associated with overweight and obesity; however, body fatness remains the most important variable associated with increased CVD risk factors in young overweight and obese adults.     

The contribution of stress to the social patterning of clinical and subclinical CVD risk factors in African Americans: The Jackson Heart Study

It is often hypothesized that psychosocial stress may contribute to associations of socioeconomic position (SEP) with risk factors for cardiovascular disease (CVD). However, few studies have investigated this hypothesis among African Americans, who may be more frequently exposed to stressors due to social and economic circumstances. Cross-sectional data from the Jackson Heart Study (JHS), a large population-based cohort of African Americans, were used to examine the contributions of stressors to the association of SEP with selected cardiovascular (CVD) risk factors and subclinical atherosclerotic disease. Among women, higher income was associated with lower prevalence of hypertension, obesity, diabetes and carotid plaque and lower levels of stress. Higher stress levels were also weakly, albeit positively, associated with hypertension, diabetes, and obesity, but not with plaque. Adjustment for the stress measures reduced the associations of income with hypertension, diabetes and obesity by a small amount that was comparable to, or larger, than the reduction observed after adjustment for behavioral risk factors. In men, high income was associated with lower prevalence of diabetes and stressors were not consistently associated with any of the outcomes examined. Overall, modest mediation effects of stressors were observed for diabetes (15.9%), hypertension (9.7%), and obesity (5.1%) among women but only results for diabetes were statistically significant. No mediation effects of stressors were observed in men. Our results suggest that stressors may partially contribute to associations of SEP with diabetes and possibly hypertension and obesity in African American women. Further research with appropriate study designs and data is needed to understand the dynamic and interacting effects of stressors and behaviors on CVD outcomes as well as sex differences in these effects.     

Exercise, body mass index, caloric intake, and cardiovascular mortality

BACKGROUND: The association of physical inactivity and elevated body mass index (BMI) with cardiovascular disease (CVD) risk is well established. The relationship of dietary caloric intake and CVD risk is less certain. METHODS: The epidemiologic follow-up of the First National Health and Nutrition Examination Survey (1971-1992) was examined to determine the relationship of caloric intake, BMI, and physical activity to CVD mortality. Of 14,407 participants, 9790 subjects aged 25 to 74 years met inclusion criteria. The CVD mortality rate was the outcome. RESULTS: During the 17 years of follow-up, there were 3183 deaths, 1531 of which were due to CVD (9.11/1000 person-years). People with relatively less physical activity, lower caloric intake, and who were overweight (BMI 25 to 29.9 kg/m(2)) and obese (BMI > or =30 kg/m(2)) had a less favorable baseline CVD risk profile than did those who were more active and of normal weight and had greater caloric intake. Age- and race/ethnicity-adjusted CVD mortality rates were highest among those with the least physical activity and lowest caloric intake, and who were overweight or obese. Moreover, subjects of normal weight who exercised most were more likely to have high caloric intake and lower CVD mortality (5.9 vs 14.7 per 1000 person-years, p =0.01) than subjects who were obese and exercised least. In Cox regression analysis, controlling for relevant CVD risk factors, least physical activity was independently associated with increased CVD mortality (hazard ratio=1.32, 95% confidence interval [CI]=1.13-1.53); and obesity was associated with increased CVD mortality (hazard ratio=1.24, 95% CI=1.06-1.44). Although highest dietary caloric intake was associated with reduced CVD mortality (hazard ratio=0.83, 95% CI=0.74-0.93), after adjusting for physical activity and BMI, there was no significant association of highest caloric intake with CVD mortality (hazard ratio=0.91, 95% CI=0.81-1.01). CONCLUSIONS: In this large general population sample, lower levels of physical activity and obesity were independently associated with decreased CVD survival. Moreover, when BMI, physical activity, and other relevant characteristics were taken into account, caloric intake was not related to CVD mortality.     

Commuting physical activity is favourably associated with biological risk factors for cardiovascular disease

Background Little is known about the effects of commuting physical activity on biological cardiovascular risk factors although such knowledge may form an important basis for interventions aimed at reducing cardiovascular disease (CVD) by increasing physical activity. We examined the associations between commuting, leisure time and total physical activity and biological risk factors for CVD. Design A cross-sectional study of men and women, who participated in a health screening programme. Methods The study population comprised persons aged 30–60 years from a population-based random sample, response rate 53% (n = 6,906). Weight, height, waist circumference and blood pressure were measured and blood samples were collected. Physical activity was assessed by a self-administered questionnaire. Results Time spent on commuting, leisure time and total physical activity was positively associated with high-density lipoprotein cholesterol and negatively associated with low-density lipoprotein cholesterol, triglycerides, waist circumference and body mass index. Time spent on total physical activity was negatively associated with total cholesterol and diastolic blood pressure. Among men there was no relationship between time spent on physical activity and systolic blood pressure. Time spent on commuting physical activity and total physical activity was negatively associated with systolic blood pressure among women. Conclusion Commuting physical activity, independent of leisure time physical activity, was associated with a healthier level of most of the cardiovascular risk factors. An increase in commuting physical activity in the population may therefore reduce the incidence of CVD.     

Sex difference in the effects of sociocultural status on diabetes and cardiovascular risk factors in Mexican Americans. The San Antonio Heart Study

The authors postulated that as Mexican Americans became more affluent and/or acculturated to "mainstream" United States life-style they would progressively lose their "obesity-related" pattern of cardiovascular risk factors which were defined as: obesity, diabetes, hypertriglyceridemia and low levels of high density lipoprotein cholesterol. This hypothesis was tested in 1979-1982 in the San Antonio Heart Study, a population-based study on 1,288 Mexican Americans and 929 Anglos living in three San Antonio neighborhoods: a low-income barrio, a middle-income transitional neighborhood, and a high-income suburb. The study population comprised 25-65-year-old men and nonpregnant women. In Mexican American women, all of the "obesity-related" risk factors fell sharply with rising socioeconomic status. In Mexican American men, by contrast, diabetes was the only "obesity-related" risk factor which fell with rising socioeconomic status. Moreover, it fell less steeply, there being an approximately twofold difference in diabetes prevalence between the barrio and the suburbs in men compared to a fourfold difference in women. Also, total and low density lipoprotein cholesterol rose with rising socioeconomic status in Mexican American men, but not in Mexican American women. "Obesity-related" risk factors were generally higher in Mexican Americans of both sexes than in their Anglo neighbors who were of similar socioeconomic status. These results suggest that cultural factors exert a stronger influence on diabetes and cardiovascular risk factors in Mexican Americans than do purely socioeconomic factors.     

The role of acculturation in nutrition, lifestyle, and incidence of type 2 diabetes among Latinos

Latinos have become the largest ethnic minority group in the U.S. and will become 25% of the population by 2050. The purpose of this critical review is to examine the influence of acculturation on type 2 diabetes and corresponding risk factors, including 1) dietary intake, 2) physical activity patterns, 3) smoking and alcohol consumption, and 4) obesity. Among Latinos, acculturation has been associated with obesity risk, suboptimal dietary choices including lack of breast-feeding, low intake of fruits and vegetables, a higher consumption of fats and artificial drinks containing high levels of refined sugar, smoking, and alcohol consumption. In contrast, acculturation has been positively associated with physical activity and a lower likelihood of type 2 diabetes among Latinos. However, findings have been inconsistent across acculturation indicators and appear to be strongly modified by Latino subethnicity and gender. It is important to improve existing acculturation measures available. Mexican Americans have been the target group in the majority of studies. Research in this group must continue but it is important to conduct additional research with other Latino subgroups that have been left out of most of the acculturation, lifestyles, and health outcomes research. Differences between acculturation and health-related outcomes may be confounded by socio-economic status, age, and movement from urban to rural areas. Longitudinal multivariate acculturation research is essential to disentangle these relations and to develop sound behavioral change theories that adequately predict behavioral change among Latinos.     

The association between physical fitness and cardiovascular disease risk factors in children in a five-year follow-up study

The relation between physical fitness and cardiovascular disease (CVD) risk factors was studied in 633 children selected from all fourth grades in 37 elementary schools in New York. They were participating in the control group of an intervention study to reduce CVD risk factors in children. Blood pressure, total and high-density lipoprotein (HDL) cholesterol and physical fitness were measured at baseline and at four subsequent examinations during five years of follow-up. Systolic blood pressure (SBP) at baseline was highest in children with poor physical fitness. The five-year change in physical fitness was inversely associated with the change in SBP, ie, children with the strongest decline in physical fitness showed the largest rise in SBP. HDL cholesterol at baseline was lowest in boys with poor physical fitness. The five-year change in physical fitness was positively related to the change in HDL cholesterol levels in boys; ie, boys with the largest decline in physical fitness had the largest decrease in HDL cholesterol level. These observations indicate that unfavourable long-term changes in physical condition in childhood may be related to unfavourable changes in blood pressure and serum lipids.     

Central adiposity and gallbladder disease in Mexican Americans

Obesity is widely recognized as a risk factor for gallstones. However, to the authors' knowledge, only one study has examined the effect of body fat distribution on the prevalence of gallbladder disease. Mexican Americans are a population characterized by both a high prevalence of gallbladder disease and an unfavorable body fat distribution. The authors examined whether central adiposity (as measured by the ratio of subscapular-to-triceps skinfold) was related to clinically evident gallbladder disease in 1,202 Mexican Americans and 908 non-Hispanic whites in the San Antonio Heart Study from 1979 to 1982. After adjustment for overall adiposity (as measured by body mass index) and the ratio of subscapular-to-triceps skinfold, an increased prevalence of gallbladder disease was still observed in Mexican-American women. Both body mass index and the ratio of subscapular-to-triceps skinfold were positively and independently associated with gallbladder disease in women, while in men, body mass index, but not the subscapular-to-triceps skinfold ratio, was associated with gallbladder disease. Central adiposity is also related to the adverse pattern of cardiovascular risk factors observed in women with gallbladder disease.     

Biogeographic ancestry, self-identified race, and admixture-phenotype associations in the Heart SCORE Study

Large epidemiologic studies examining differences in cardiovascular disease (CVD) risk factor profiles between European Americans and African Americans have exclusively used self-identified race (SIR) to classify individuals. Recent genetic epidemiology studies of some CVD risk factors have suggested that biogeographic ancestry (BGA) may be a better predictor of CVD risk than SIR. This hypothesis was investigated in 464 African Americans and 771 European Americans enrolled in the Heart Strategies Concentrating on Risk Evaluation (Heart SCORE) Study in March and April 2010. Individual West African and European BGA were ascertained by means of a panel of 1,595 genetic ancestry informative markers. Individual BGA varied significantly among African Americans and to a lesser extent among European Americans. In the total cohort, BGA was not found to be a better predictor of CVD risk factors than SIR. Both measures predicted differences in the presence of the metabolic syndrome, waist circumference, triglycerides, body mass index, very low density lipoprotein cholesterol, lipoprotein A, and systolic and diastolic blood pressure between European Americans and African Americans. These results suggest that for most nongenetic cardiovascular epidemiology studies, SIR is sufficient for predicting CVD risk factor differences between European Americans and African Americans. However, higher body mass index and diastolic blood pressure were significantly associated with West African BGA among African Americans, suggesting that BGA should be considered in genetic cardiovascular epidemiology studies carried out among African Americans.     

Excess stroke in Mexican Americans compared with non-Hispanic Whites: the Brain Attack Surveillance in Corpus Christi Project

Mexican Americans are the largest subgroup of Hispanics, the largest minority population in the United States. Stroke is the leading cause of disability and third leading cause of death. The authors compared stroke incidence among Mexican Americans and non-Hispanic Whites in a population-based study. Stroke cases were ascertained in Nueces County, Texas, utilizing concomitant active and passive surveillance. Cases were validated on the basis of source documentation by board-certified neurologists masked to subjects' ethnicity. From January 2000 to December 2002, 2,350 cerebrovascular events occurred. Of the completed strokes, 53% were in Mexican Americans. The crude cumulative incidence was 168/10,000 in Mexican Americans and 136/10,000 in non-Hispanic Whites. Mexican Americans had a higher cumulative incidence for ischemic stroke (ages 45-59 years: risk ratio = 2.04, 95% confidence interval: 1.55, 2.69; ages 60-74 years: risk ratio = 1.58, 95% confidence interval: 1.31, 1.91; ages >or=75 years: risk ratio = 1.12, 95% confidence interval: 0.94, 1.32). Intracerebral hemorrhage was more common in Mexican Americans (age-adjusted risk ratio = 1.63, 95% confidence interval: 1.24, 2.16). The subarachnoid hemorrhage age-adjusted risk ratio was 1.57 (95% confidence interval: 0.86, 2.89). Mexican Americans experience a substantially greater ischemic stroke and intracerebral hemorrhage incidence compared with non-Hispanic Whites. As the Mexican-American population grows and ages, measures to target this population for stroke prevention are critical.     

Impact of age at smoking initiation, dosage, and time since quitting on cardiovascular disease in african americans and whites: the atherosclerosis risk in communities study

Despite reportedly having less tobacco exposure compared with whites, African Americans account for a disproportionate number of smoking-related deaths. The purpose of this study was to compare the prospective associations between smoking and cardiovascular risk in whites and African Americans. Smoking status was obtained on 14,200 participants from the Atherosclerosis Risk in Communities Study. Incidence of cardiovascular disease (CVD) was ascertained from 1987 through 2007. Adjusted Cox proportional hazard models were used to estimate the CVD incidence associated with smoking behavior. Over 17 years' follow-up, there were 2,777 cardiovascular events. In men, compared with never smoking, current smoking was independently associated with 67% (95% confidence interval (CI): 43, 95) and 72% (95% CI: 30, 126) greater risk of CVD in whites and African Americans, respectively. In women, the smoking-related cardiovascular risk was higher: 136% (95% CI: 88, 196) and 169% (95% CI: 126, 219) in African-American and white women, respectively. Early age at smoking initiation was independently associated with increased risk among all participants irrespective of race. Smoking cessation during follow-up was equally beneficial in both whites and African Americans. African Americans who smoke incur a similar level of cardiovascular risk as white smokers and would derive the same benefits from quitting as whites.     

The associations between current recommendation for physical activity and cardiovascular risks associated with obesity

OBJECTIVE: To examine associations between current recommended physical activity levels and body mass index (BMI) with some cardiovascular disease (CVD) risk factors (total cholesterol, high-density lipoprotein cholesterol (HDL-C), non-HDL-cholesterol (non-HDL-C), C-reactive protein (CRP), fibrinogen, and blood pressure), general health score (GHQ12) and predicted coronary heart disease (CHD) risk. DESIGN: Further analysis of the cross-sectional Scottish Health Survey 1998 data. SUBJECTS: Five thousand four hundred and sixty adults 16-74 years of age. RESULTS: After controlling for some confounding factors, obesity was significantly associated with higher odds ratio (OR) for elevated cholesterol, CRP, systolic blood pressure, non-HDL-C and lower HDL-C (P<0.001), and with greater predicted CHD risk compared to BMI <25 kg/m(2). Regular self-reported physical activity was associated with smaller OR of lower HDL-C and higher CRP, and average predicted 10-year CHD risk in obese subjects, but did not eliminate the higher risk of the measured CVD risk factors in this group. The OR of these two risk factors were still high 4.39 and 2.67, respectively, when compared with those who were inactive with BMI <25 kg/m(2) (P<0.001). Those who reported being physically active had better GHQ scores in all BMI categories (P<0.001). CONCLUSION: Reporting achievement of recommended physical activity levels may reduce some CVD risk factors, predicted CHD risk and improve psychosocial health, but may not eliminate the extra risk imposed by overweight/obesity. Therefore, increasing physical activity and reducing body weight should be considered to tackle CVD risk factors.     

Composition (lean and fat tissue) of weight changes in adult Danes

BACKGROUND: Weight loss may be associated with unfavorable changes in body composition not compensated for by subsequent weight gain. OBJECTIVE: We examined the composition of weight change in relation to obesity, previous weight changes, weight-loss attempts, and physical activity. DESIGN: Part of the Danish MONICA (Monitoring Trends in Cardiovascular Disease) project, this was a longitudinal population study of changes in weight and body composition, with examinations in 1982-1983, 1987-1988, and 1993-1994. A total of 1236 men and 1200 women aged 35, 45, 55, or 65 y in 1987-1988 participated. Changes in fat and fat-free mass were measured by bioelectrical impedance. RESULTS: Before adjustment for age-related changes, fat-free mass made up 41% of weight lost and 24% of weight gained in men. In women, loss of fat-free mass (35%) was more than double that of gains (15%). After adjustment, the fractions of weight gained as fat-free mass were not significantly different from the fractions lost. These fractions were independent of age, obesity, and weight changes in the previous 5 y; successful weight-loss attempts; and physical activity. Independent of age and degree of obesity, weight changes were associated with greater changes in fat-free mass in men than in women. CONCLUSIONS: These data do not support the theory that weight loss or weight cycling may lead to an unfavorable body composition, nor do they provide a biological explanation for why long-term weight loss is often unsuccessful. However, the metabolic and health consequences of weight change may differ in men and women.     

Prevalence of pre-obesity and obesity in urban adult Mexicans in comparison with other large surveys

OBJECTIVE: 1. To estimate the prevalence of pre-obesity and obesity in a 1992 to 1993 national survey of the Mexican urban adult population. 2. To compare our findings with other national surveys and with data for Mexican Americans. RESEARCH METHODS AND PROCEDURES: The national representative sample of the Mexican urban adult population included 8462 women and 5929 men aged 20 to 69 years from 417 towns of >2500 people. Body mass index (BMI), calculated from measured weight and height, was classified using the World Health Organization categories of underweight (BMI < 18.5 kg/m2), normal weight (BMI 18.5 to 24.9 kg/m2), pre-obesity (PreOB = BMI 25 to 29.9 kg/m2) and obesity (OB = BMI 30+ kg/m2). Estimates for Mexican Americans were calculated from U.S. survey data. RESULTS: Overall, 38% of the Mexican urban adult population were classified as pre-obese and 21% as obese. Men had a higher prevalence of pre-obesity than women did at all ages, but women had higher values of obesity. Both pre-obesity and obesity increased with age up to the age range brackets of 40 to 49 or 50 to 59 years for both men and women. Both pre-obesity and obesity prevalence estimates were remarkably similar to data for Mexican Americans from 1982 through 1984. Comparison with other large surveys showed that countries differed more in the prevalence of obesity than of pre-obesity, leading to differences in the PreOB/OB ratio, and that countries also differed in the gender ratio (female/male) for both pre-obesity and obesity. DISCUSSION: Pre-obesity and obesity were high in our population and increased with age. Our approach of characterizing large surveys by PreOB/OB and gender ratios appeared promising.     

Indices of adipose tissue distribution, apolipoproteins B and AI, lipoprotein (a), and triglyceride concentration in children aged 4-11 years: the Third National Health and Nutrition Examination Survey

This study examined the association of body fat distribution with serum apolipoproteins, lipoprotein (a), and triglyceride, risk factors for cardiovascular morbidity, in a representative sample of U.S. black, white, and Hispanic children. Data from the Third National Health and Nutrition Examination Survey for children aged 4-11 years revealed the mean waist-to-hip ratio (WHR) varied consistently with age, gender, and ethnic group. Levels were highest in Mexican Americans. WHR showed significant negative associations with apo AI concentration and positive associations with apo B and the ratio of apo B to apo AI independent of age but not body mass index (BMI). Associations of WHR with serum triglyceride concentration were independent of age and BMI. Other indices of body fat distribution were not superior to WHR. Lp (a) was not consistently associated with WHR. In conclusion, after controlling for BMI and age, body fat distribution was not significantly associated with apo AI and apo B with few exceptions. Nor was Lp (a) significantly associated with body fat distribution. Casual serum triglyceride levels were significantly positively associated with WHR independent of age and BMI in non-Hispanic white and Mexican American children.