The relative contribution of body fat and fat pattern to blood pressure level

Blood Cholesterol and Triglycerides in Adolescent Egyptian Girls: Relation to Anthropometric Measurements

High serum cholesterol is a major risk factor for atherosclerosis. This cross-sectional study (n = 102) investigated the levels of total cholesterol (TC) and triglycerides (TG) in Egyptian girls aged 11 to 16 years attending a middle-class public school. The mean TC level was 194.27 ± 21.97 mg/dl, and 33.33% of girls had TC levels > 200 mg/dl. The mean TG level was 160.07 ± 30.83 mg/dl, with 3.92% of the girls showing TG levels > 2 00 mg/dl. Most of the girls (65.69%) were overweight, with body mass index (BMI) >25. Univariate analyses revealed an association of TC and TG with all anthropometric measures. Using stepwise regression analyses, the best model for prediction of TC was with BMI and central body fat (explaining 24.76% of TC variance); the final model for TG was with BMI, central body fat, and abdominal skinfold thickness (explaining 47.49% of TG variance). Our data show that these adolescent Egyptian girls were heavier and had higher blood lipid concentrations than subjects in the Bogalusa study and other studies worldwide. Further studies are needed to determine the factors associated with these higher lipid levels and to develop appropriate intervention programmes.

Changes in fat mass and fat-free-mass are associated with incident hypertension in four population-based studies from Germany

BACKGROUND

We estimated the association of changes in body weight, waist circumference (WC), fat mass (FM) and fat-free mass (FFM) with changes in blood pressure and incident hypertension using data from four German population-based studies.

METHODS

We analyzed data from 4467 participants, aged 21 to 82 years not taking antihypertensive medication and not having type 2 diabetes mellitus or a history of myocardial infarction at baseline and follow-up, from four population-based studies conducted in Germany. Body weight, WC, and blood pressure were measured at baseline and follow-up (median follow-up of the single studies 4 to 7 years). FM and FFM were calculated based on height-weight models derived from bioelectrical impedance studies. Hypertension was defined as systolic blood pressure ≥ 140 mmHg or diastolic blood pressure ≥ 90 mmHg. Confounder-adjusted linear and logistic regressions were used to associate changes in anthropometric markers with changes in blood pressure, incident hypertension, and incident normalization of blood pressure.

RESULTS

In a pooled dataset including all four studies, increments in body weight, WC, FM, and FFM were statistically significantly associated with incident hypertension and changes in systolic and diastolic blood pressure over time. Decreases in body weight, FM, and FFM were significantly associated with incident normalization of blood pressure.

CONCLUSIONS

Our data suggests that the well-established association between obesity and blood pressure levels might be more related to body composition rather than to total body weight per se. Our findings indicate that gaining or losing FFM has substantial impact on the development or reversion of hypertension.

Prevalence and distribution of hypertension and related risk factors in Jilin Province, China 2015: a cross-sectional study

OBJECTIVE

This study aimed to investigate the prevalence and distribution of hypertension and its related factors in Jilin province, China.

DESIGN

A cross-sectional study in four cities and four rural counties in Jilin as part of a national Chinese study.

PARTICIPANTS AND SETTING

A total of 15 206 participants who were ≥15 years old and were selected using a stratified multistage random sampling method.

MAIN OUTCOME MEASURES

The prevalence of hypertension.

RESULTS

The prevalence of hypertension in Jilin province was 24.7%. Moreover, the prevalence of hypertension increased with age in both sexes, and was higher in men than in women. The modifiable factors that were associated with hypertension were body mass index, smoking and alcohol drinking. The risk factors identified are similar to those in southern China, except smoking, which has no association with hypertension prevalence in the South.

CONCLUSIONS

Age, sex, body mass index, smoking and alcohol drinking were risk factors of hypertension. Control of these related risk factors, especially smoking, may be helpful in the treatment and management of hypertension in Jilin province.

AFestschriftfor Roland L. Weinsier: Nutrition Scientist, Educator, and Clinician1

Roland L. Weinsier, M.D., Dr.P.H., devoted himself to the fields of nutrition and obesity for more than 35 years. He contributed outstanding work related to the treatment of obesity through dietary and lifestyle change; metabolic/energetic influences on obesity, weight loss, and weight regain; body composition changes accompanying weight loss and regain; the health benefits and risks of weight loss; nutrition education for physicians; and nutrition support of sick patients. He served on the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) National Task Force on Prevention and Treatment of Obesity, as Chair of the University of Alabama at Birmingham's Department of Nutrition Sciences, and as Founder and Director of its NIDDK-funded Clinical Nutrition Research Center. He was a long-time and active member of NAASO, serving in the roles of Councilor, Publications Committee Chair, Continuing Medical Education Course Director, Public Relations Committee Chair, and Membership Committee Co-Chair, to name just a few. He was well respected as a staunch defender of NAASO's scientific integrity in these roles. Sadly, Roland Weinsier died on November 27, 2002. He will be missed and remembered by many as a revered and beloved teacher, mentor, healer, and scholar.

Weight science: evaluating the evidence for a paradigm shift

Current guidelines recommend that "overweight" and "obese" individuals lose weight through engaging in lifestyle modification involving diet, exercise and other behavior change. This approach reliably induces short term weight loss, but the majority of individuals are unable to maintain weight loss over the long term and do not achieve the putative benefits of improved morbidity and mortality. Concern has arisen that this weight focus is not only ineffective at producing thinner, healthier bodies, but may also have unintended consequences, contributing to food and body preoccupation, repeated cycles of weight loss and regain, distraction from other personal health goals and wider health determinants, reduced self-esteem, eating disorders, other health decrement, and weight stigmatization and discrimination. This concern has drawn increased attention to the ethical implications of recommending treatment that may be ineffective or damaging. A growing trans-disciplinary movement called Health at Every Size (HAES) challenges the value of promoting weight loss and dieting behavior and argues for a shift in focus to weight-neutral outcomes. Randomized controlled clinical trials indicate that a HAES approach is associated with statistically and clinically relevant improvements in physiological measures (e.g., blood pressure, blood lipids), health behaviors (e.g., eating and activity habits, dietary quality), and psychosocial outcomes (such as self-esteem and body image), and that HAES achieves these health outcomes more successfully than weight loss treatment and without the contraindications associated with a weight focus. This paper evaluates the evidence and rationale that justifies shifting the health care paradigm from a conventional weight focus to HAES.

Waist-to-hip ratio is a better anthropometric index than body mass index for predicting the risk of type 2 diabetes in Taiwanese population

Body mass index (BMI) has been reported to be related to the risk of type 2 diabetes and hypertension. However, waist circumference or waist-to-hip ratio (WHR) can better reflect the accumulation of intra-abdominal fat and might be a better predictor than BMI of the risk of type 2 diabetes and hypertension. We hypothesized that other anthropometric indices rather than BMI could more accurately predict the risk of type 2 diabetes and hypertension. The purpose of this study was to determine which anthropometric index can be a better predictor for forecasting the risk of type 2 diabetes and hypertension in the Taiwanese population. We conducted a cross-sectional study and reviewed data derived from the Nutrition and Health Survey in Taiwan, 1993-1996. The subjects were 2545 men and 2562 women, aged 18 to 96 years. Receiver operating characteristic curve analysis was used to measure the predictive diabetic and hypertensive performance of each anthropometric measurement based on the area under the curve (AUC). Among 5 anthropometric indices, WHR had a significantly adjusted odds ratio (OR) and the highest AUC (0.72 for men and 0.80 for women) to predict the risk of type 2 diabetes. Although BMI had a significantly adjusted OR, the AUC was not the highest among the 5 anthropometric indices used to predict the risk of hypertension. Our findings suggested that WHR is a better anthropometric index for predicting the risk of type 2 diabetes, and the optimal cutoff values of WHR are considered as 0.89 for men and 0.82 for women in the Taiwanese population.

Regional obesity and coronary artery atherosclerosis in females: a non-human primate model

The relationships between regional obesity, atherosclerosis and atherosclerosis risk factors were studied in female cynomolgus monkeys (Macaca fascicularis). In a retrospective necropsy study it was found that females with relatively high central: peripheral fat deposition had three times more extensive coronary artery atherosclerosis. In a second experiment it was found that females with high central fat ratios and females with high levels of whole body obesity were relatively hyperglycemic. In a third experiment it was found that females with relatively high whole body obesity, and females with relatively central fat deposition had higher blood pressures. Females with relatively central fat deposition had higher total and lower high density lipoprotein plasma cholesterol concentrations, and exacerbated coronary artery atherosclerosis. Social subordinates were more likely to exhibit a central fat deposition pattern than dominants. These findings suggest that female cynomolgus macaques may be a potential animal model of the health impact of regional obesity.

Relationship of anthropometric measurements of body fat distribution to metabolic profile in premenopausal women

Regional fat distribution has emerged as an independent predictor of metabolic aberrations including glucose intolerance, hyperinsulinemia, insulin resistance, hyperlipidemia and hypertension. We investigated the comparative efficacy of various body fat distribution indices in predicting these aberrations. The relationship of circumferential ratios, skinfold measurements, and computerized tomography (CT)-derived indices of intra- and extra-abdominal fat distribution to the metabolic variables and blood pressure was examined in a cohort of healthy premenopausal women. All indices denoting preponderance of fat in the central, upper body or abdominal region were predictive of the metabolic profile. The subscapular skinfold, subscapular-triceps ratio, waist-hip ratio (WHR), and the CT derived intra-abdominal fat area (CT-IFA) were closely related to alterations in glucose and insulin concentrations independent of age and obesity. The WHR and CT-IFA were better predictors of plasma triglyceride levels and blood pressure profile and thus the overall aberrations than skinfold measurements. Despite a high degree of intercorrelation between the anthropometric indices measured, only the relationship of WHR to CT-IFA remained significant after adjusting for the effects of age and degree of adiposity, suggesting that WHR indexes not only the relative distribution of truncal to gluteofemoral subcutaneous fat but also the abundance of intra-abdominal or visceral fat depots. The greater reproducibility of CT-IFA and WHR also suggests that these measurements are the most useful in predicting the regional obesity-associated metabolic abnormalities with their morbidity and mortality risks.

Association between body composition and blood pressure in a contemporary cohort of 9-year-old children

Elevated blood pressure (BP) in children is an early risk factor for cardiovascular disease and is positively associated with body mass index (BMI). However, BMI does not distinguish between fat and lean masses, and the relationship of BP in children to different elements of body composition is not well established. BP, BMI and body composition were measured in 6863 children enrolled in the Avon Longitudinal Study of Parents and Children. Fat mass, lean mass and trunk fat were assessed using dual-energy X-ray absorptiometry. After full adjustment for confounders, total body fat and BMI were positively associated with systolic blood pressure (SBP) (beta=3.29, 95% confidence interval CI 3.02, 3.57 mm Hg/standard deviation (s.d.) and beta=3.97, 95% CI 3.73, 4.21 mm Hg/s.d., respectively) and diastolic blood pressure (DBP) (beta=1.26, 95% CI 1.05, 1.46 mm Hg/s.d. and beta=1.37, 95% CI 1.19, 1.54 mm Hg/s.d., respectively). SBP was also positively associated with lean mass (beta=3.38, 95% CI 2.95, 3.81 mm Hg/s.d.), and weakly associated with trunk fat (beta=1.42, 95% CI -0.06, 2.90 mm Hg/s.d., independent of total fat mass), which was robust in girls only. The association between lean mass and SBP remained even after accounting for fat mass. SBP in 9-year-old children is independently associated with fat mass and lean mass and, to a lesser extent, trunk fat in girls. In this analysis, because both fat and lean masses are associated with BP, BMI predicts BP at least as well as these components of body composition.

Body mass index in primary and secondary pediatric hypertension

The objectives of this study were (1) to determine the relationship of body mass index (BMI) to primary or secondary hypertension in children and adolescents and (2) to assess BMI at the age of onset of hypertension in children and adolescents. Patient demographics, BMI, family history, presentation of disease, etiology of hypertension, medication, laboratory data, and findings from other procedures were recorded for all patients with hypertension followed in the Pediatric Nephrology Clinic at Children's Hospital, Columbus, Ohio, over a 4-year period. In total, 314 patients were studied: 218 with primary hypertension and 96 with secondary hypertension. Our patient population (166 males, 148 females) was diverse in age (13+/-6.3 years) and ethnicity (237 Caucasians, 54 African-Americans, 23 other). BMI was greater in patients with primary (27.5+/-9.2 kg/m2) versus secondary (23.9+/-9.3 kg/m2) hypertension (P=0.002). Children with primary hypertension with an increased BMI presented at an earlier age than children with secondary hypertension and an increased BMI. The age of onset (10.5+/-2.6 years) in primary hypertension was related to increased BMI (r=0.12, P=0.001); however, there was no relationship between BMI and age of onset of secondary hypertension (P=0.21). Children whose family members had essential hypertension had increased BMI compared with children without a family history of essential hypertension. Based on the logistic regression model constructed from our data, the likelihood of primary versus secondary hypertension was influenced by the presence of family history of hypertension independent of presence of obesity in the child. In conclusion, increased BMI is more common in children with primary than secondary hypertension; earlier onset of primary hypertension in the pediatric population was associated with increased BMI; the assessment of BMI is important in the evaluation of secondary as well as primary hypertension; the role of obesity in the development of secondary as well as primary hypertension in children merits further study.

The epidemiology of central fat distribution in relation to disease

The effect of fat distribution on disease risk is a subject of great interest. Central fat has been measured anthropometrically, by computed tomography, and by magnetic resonance imaging. Both cross-sectional and longitudinal studies have related central fat to type 2 diabetes mellitus and cardiovascular disease, independent of body mass index. The mechanism may relate to increased lipolysis causing the liver to increase glucose and very low density lipoprotein output, while muscle uses less. This leads to a rise in blood glucose and triglycerides, a drop in HDL cholesterol, and an increase in small, dense LDL particles. There is also an increase in blood pressure and inflammatory markers. Certain populations put on excess fat more centrally than others. These include Asian populations. It is likely that with better differentiation of abdominal fat into visceral and subcutaneous depots, clearer data will accrue on their impact on disease risk.

Systemic hypertension and obstructive sleep apnoea

This article is a review of the current evidence that links systemic hypertension with obstructive sleep apnoea. Whilst a causal association has been suspected for some time, the day to day variability of both blood pressure and sleep apnoea severity, and clustering of confounding cardiovascular risk factors in sleep apnoea patients has made this association difficult to prove. There is unassailable evidence that obstructive apnoeas raise blood pressure acutely in both animal models and humans, through a combination of autonomic and state dependent arousal with some mechanical influences, and these rises can be controlled by nasal continuous positive airway pressure. Thus, although repetitive apnoeas alter the blood pressure variability and raise sleeping blood pressure in patients with OSA and sophisticated animal models have demonstrated increases in daytime blood pressure after the onset of OSA in the short term, such effects on diurnal BP have yet to be proven in humans. Recent rigorously designed large epidemiological studies have proven an independent association between OSA and systemic hypertension in both general and sleep clinic populations, with closely matched case control series also reporting raised blood pressure in OSA patients. A direct temporal causal association between the onset of obstructive sleep apnoea and raised blood pressure is expected to be confirmed by longitudinal data from the continuing epidemiological population studies. Finally, several studies on the beneficial effects of nasal continuous positive airway pressure in reducing blood pressure in OSA patients have preliminary results in abstract form, with one published in full.

Case-control study of 24 hour ambulatory blood pressure in patients with obstructive sleep apnoea and normal matched control subjects

BACKGROUND

There is considerable debate regarding the relationship between obstructive sleep apnoea (OSA) and hypertension. It is unclear whether OSA is an independent vascular risk factor as studies attempting to assess this association have produced conflicting results because of confounding variables such as upper body obesity, alcohol, and smoking. A case-control study of 24 hour ambulatory blood pressure was undertaken in patients with OSA and matched controls to assess whether OSA is an independent correlate of diurnal hypertension.

METHODS

Forty five patients with moderate to severe OSA and excessive daytime sleepiness were matched with 45 controls without OSA in a sleep study. Matched variables included age, body mass index (BMI), alcohol, cigarette usage, treated hypertension, and ischaemic heart disease. Upper body obesity was compared by waist:hip and waist:height ratios; 24 hour ambulatory blood pressure recordings were performed (before treatment for OSA) in all subjects.

RESULTS

Patients with OSA had significantly increased mean (SD) diastolic blood pressure (mm Hg) during both daytime (87.4 (10.2) versus 82.8 (9.1); p=0.03, mean difference 4.6 (95% CI 0.7 to 8.6) and night time (78.6 (9.3) versus 71.4 (8.0); p<0.001, mean difference 7.2 (95% CI 3.7 to 10.6)), and higher systolic blood pressure at night (119.4 (20.7) versus 110.2 (13.9); p=0.01, mean difference 9.2 (95% CI 2.3 to 16.1)). The nocturnal reduction in blood pressure ("dipping") was smaller in patients with OSA than in control subjects.

CONCLUSIONS

Compared with closely matched control subjects, patients with OSA have increased ambulatory diastolic blood pressure during both day and night, and increased systolic blood pressure at night. The magnitude of these differences is sufficient to carry an increased risk of cardiovascular morbidity. The slight excess of upper body fat deposition in the controls may make these results conservative.

Comparison of anthropometric characteristics between normotensive and hypertensive individuals among a population of Bengalee Hindu elderly men in Calcutta, India

A comparative investigation of 99 normotensive and 111 hypertensive Bengalee Hindu elderly men (aged 55 years and above) of Kalighat, South Calcutta, India, was undertaken to study differences in levels of adiposity, body fat distribution and body composition between these two groups. Results revealed that there were significant differences between normotensive (NT) and hypertensive (HT) subjects in the mean values for weight (p < 0.05), body mass index (BMI, p < 0.01); waist (p < 0.001) and hip circumferences (p < 0.05); waist-hip ratio (WHR, p < 0.001), conicity index (CI, p < 0.01) and fat free mass (FFM, p < 0.001). Percentile distributions for all these variables and indices showed consistently higher values among the HT patients as compared with NT subjects. However, the frequency of obesity (BMI > or = 25) was similar (NT = 6.1%, HT = 11.7%) in both groups. Thus, these results indicated that there existed significant differences in central adiposity and FFM between NT and HT subjects although their level of obesity was similar. Hypertensive individuals have significantly enhanced levels of central body fat distribution.

Dyslipidemia and abdominal obesity: an assessment in three general populations

Several studies show a relationship between abdominal obesity and cardiovascular diseases, partially mediated through an altered metabolism of dyslipidemia. The present study was aimed at testing the robustness of this association across three contrasted populations and at assessing the performances of abdominal obesity as a screening tool for dyslipidemia. Data were drawn from three population health surveys recently conducted in two regions of a developed country (Switzerland, mostly of Caucasian origin, n = 2650) and in a less developed country (Seychelles, Indian Ocean, mostly of black descent, n = 806). Dyslipidemia was defined as a ratio of total cholesterol to high-density lipoprotein cholesterol (TC-HDL) greater than 5. Two anthropometric circumference measurements, waist-to-hip ratio (WHR) and waist circumference (WC), were used to define abdominal obesity either as WHR >/= 0.9 in men and WHR >/= 0.8 in women or as WC >/= 94 cm and WC >/= 80 cm, respectively. A consistent direct association between abdominal obesity and dyslipidemia (odds ratios varying from 1.85 to 4.56) was found in the three populations, independently of gender, age, body mass index, blood pressure, and smoking. This consistency across ethnicities and environments strengthens the hypothesis of a common etiopathological mechanism. The sensitivity for detecting dyslipidemia was generally higher for abdominal obesity, based on either WHR or WC, than for criteria based on the other risk factors under study. In addition, the sensitivity was higher in the study populations with a low prevalence of dyslipidemia (Swiss women and Seychellois of both sexes) than in the others. These findings support that WHR and WC may be useful as simple and inexpensive screening tools to select individuals eligible for more sophisticated and costly serum lipid determinations, especially in developing countries.

Health risks among Japanese men with moderate body mass index

BACKGROUND

Despite the westernized lifestyle, most Japanese are not prominently obese. As their obesity may be obscured, we want to further explore central fat distribution and health risks among this population.

METHODS

2668 men (body mass index (BMI) 20- < 26.4 kg/m2) were identified from 3343 men (BMI 14.0-37.7, median of waist-to-height ratio (W/Ht) 0.50) who underwent routine health examinations. They were divided into four groups: (1) BMI 20- < 24, W/Ht < 0.50; (2) BMI 20- < 24, W/Ht > or = 0.50; (3) BMI 24- < 26.4, W/Ht < 0.50; and (4) BMI 24- < 26.4, W/Ht > or = 0.50. The metabolic risks and physical activities were compared.

RESULTS

W/Ht > or = 0.50 comprised 35% of the subjects of BMI 20- < 24, 91% of BMI 24- < 26.4, only 1% of BMI < 20 and up to 99% of BMI > or = 26.4. After adjusting for age and smoking and with group 1 as the reference group, odds ratios (ORs) were significantly higher in both groups 2 and 4 for the risk of hypertension (1.42, 1.98), hyperglycaemia (1.49, 1.78), hypertriglyceridaemia (1.95, 2.56), low HDL cholesterol (1.87, 2.20), hyperuricaemia (2.00, 2.51) and fatty liver (2.57, 5.64) and additionally in group 4 for hypercholesterolaemia (1.35). ORs in group 3 were only significantly higher for risk of hypertension (1.86) and fatty liver (1.89). Significantly lower frequencies of regular physical activity were noted in the higher W/Ht groups (0.75, 0.47, 1.10, 0.52 days per week, from groups 1-4, respectively).

CONCLUSIONS

Measurement of waist circumference may be a preliminary method for the survey of people at higher risk of lifestyle-related disorders in Japanese men, especially among those with moderate BMI.

Blood pressure in relation to obesity, insulin and the hypothalamic-pituitary-adrenal axis in Swedish men

OBJECTIVE

Some studies have shown a clustering of obesity, insulin and hypertension. The present study was performed to further characterize these associations.

SUBJECTS AND METHODS

In a population of 51-year-old men (n=284), measurements of systolic and diastolic blood pressure were analyzed in relation to general obesity (body mass index) and central obesity (waist: hip circumference ratio and abdominal sagittal diameter), and to the fasting insulin and insulin: glucose ratio as an approximation of insulin sensitivity. The regulation of diurnal cortisol secretion was examined in repeated salivary samples.

RESULTS

Linear regression analysis showed that all three parameters of obesity were significantly and strongly related to both systolic and diastolic blood pressure, more powerfully than insulin, glucose and insulin sensitivity (insulin: glucose ratio). Stepwise multiple regression showed that only central obesity, measured as the abdominal sagittal diameter, remained significantly (P< 0.001), and independently of insulin and insulin sensitivity, associated with both systolic and diastolic blood pressure (beta=7.5 and 4.2, respectively). A diurnal cortisol curve with normal rhythm was associated with lower than average blood pressures (P< 0.001) but not with insulin levels or the heart rate. In contrast, a flattened diurnal cortisol curve, indicating perturbations in the activity of the hypothalamic-pituitary-adrenal axis, was directly related to blood pressures, heart rate and insulin (P<0.001), and has previously been found to be strongly associated with abdominal obesity.

CONCLUSIONS

These findings suggest that general and central obesity is independently related to blood pressure, and that insulin may account for only part of this association. The activity of the hypothalamic-pituitary-adrenal axis is apparently important for blood pressure regulation, suggesting that mechanisms of the central nervous system have an impact.

Influence of body fatness on the coronary risk profile of physically active postmenopausal women

We have shown previously that endurance-trained postmenopausal runners demonstrate more favorable coronary heart disease (CHD) risk factors compared with age-matched sedentary women. However, the runners exhibited higher levels of physical activity and lower levels of body fatness, both of which can influence CHD risk factors. To gain insight into the influence of body fatness per se, we studied 38 postmenopausal healthy women: 10 swimmers, 10 runners, and nine obese and nine leaner sedentary subjects matched for age, hormone replacement use, and years postmenopause. Swimmers and runners were further matched for exercise training volume (4.5+/-0.2 v 4.6+/-0.6 h/wk) and relative competitive performance (79%+/-5% v 77+/-3% of age-adjusted world record). Maximal oxygen consumption (VO2max) on the treadmill was lower (P < .01) in swimmers versus runners. Body mass (65.0+/-2.0 v 59.0+/-1.3 kg), percent body fat (29%+/-2% v 23%+/-2%), and waist circumference (79+/-3 v 71+/-1 cm) were greater (P < .01) in swimmers than in runners. There were no significant differences in total caloric intake or dietary composition between swimmers and runners. Insulin sensitivity (via Bergman's minimal model) and fasting plasma concentrations of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), triglyceride (TG), glucose, and plasminogen activator inhibitor-1 (PAI-1) activity were not different between the groups. However, plasma high-density lipoprotein cholesterol (HDL-C), HDL2-C, HDL-C/TC, insulin, fibrinogen, fibrin D-dimer, PAI antigen, tissue plasminogen activator (t-PA) activity, and t-PA antigen levels all were less favorable (P < .05) in swimmers versus runners. Daytime, nighttime, and 24-hour systolic blood pressure (SBP) was 6 to 10 mm Hg higher in swimmers compared with runners, but resting blood pressure, 24-hour blood pressure load, and blood pressure variability were not significantly different. Stepwise regression showed that measures of body fatness were the primary independent determinants of most of the metabolic CHD risk factors. When analysis of covariance (ANCOVA) was performed with body fatness as a covariate, differences in CHD risk factors between swimmers and runners were abolished (P=.18 to .90). We conclude that among endurance-trained postmenopausal women matched for training volume and competitive eliteness, higher total and abdominal body fatness is, in general, associated with a less favorable metabolic CHD risk profile. Thus, high levels of habitual aerobic exercise do not appear to negate the deleterious effects of adiposity on the coronary risk profile of healthy middle-aged and older women.

Exaggerated blood pressure response to exercise: importance of resting blood pressure

Normotensive individuals who exhibit an exaggerated blood pressure (BP) response to exercise have an increased risk of future hypertension. However, previous studies failed to control for resting BP despite the fact that an elevated resting BP in the normotensive range is also a strong predictor of future hypertension. Therefore, we determined whether maximal systolic BP is associated with resting BP. Resting BP was measured in 68 healthy normotensive men on three separate days. The subjects then performed a graded, maximal exercise test on a Monark cycle ergometer. Maximal systolic BP was strongly correlated with resting systolic BP (r = 0.64, P < 0.0001). Subjects with elevations in systolic BP during maximal exercise (> 220 mmHg) also had higher (P < 0.005) resting BP than those without (< 220 mmHg). When stepwise regression analyses were performed, systolic BP at rest was a significant independent predictor of maximal systolic BP, explaining over 40% of the variability. These results suggest that exaggerated BP response as a predictor of future hypertension reported in previous studies may be little more than a simple reflection of elevated resting BP. Specifically, these studies should not be interpreted as demonstrating that exercise BP is a better predictor of future hypertension than resting BP alone. In the future, defining the BP 'response' to exercise as a change score (i.e. maximal BP minus resting BP) may be advantageous as it permits the effects of exercise to be examined independently of the level of resting BP.

Aldosterone in obesity

Plasma aldosterone levels were measured in adults whose body mass index ranged from lean to obese. Blood was drawn while subjects rested supine for 30-90 minutes. Aldosterone was higher in obese subjects, but could not be explained by renin or K+. The best predictors of plasma aldosterone were abdominal obesity measured as waist/hip ratio or by CT scan, and insulin resistance measured by insulin or oral glucose tolerance tests, or euglycemic clamp. In one cohort, these correlations were limited to women; in the other, they were also found in men. In the women with a strong correlation between aldosterone and visceral fat, aldosterone also correlated with cortisol and DHEA-S. The data are consistent with an effect of visceral fat on adrenal steroidogenesis. Visceral adipocytes have a high rate of triglyceride turnover, and their circulation drains directly to the liver. In an experiment based on these characteristics, rat hepatocytes responded to fatty acids by releasing an unidentified secretagogue that stimulated aldosterone production by rat adrenal glomerulosa cells. The clinical data suggest that aldosterone participates in hypertension associated with the "Insulin Resistance Syndrome". The adrenal in viscerally obese subjects may be driven by a secretagogue released from the liver by fatty acids from abdominal adipocytes.

Blood pressure and adiposity: A comparative study of socioeconomically diverse groups of Andhra Pradesh, India

The effect of adiposity on blood pressures, systolic (SBP), and diastolic (DBP), was examined in a sample of 1119 individuals (456 males, 663 females), 18-75 years, from socioeconomically diverse populations from Southern Andhra Pradesh, India. The populations were graded into four socioeconomic groups, group I-seminomadic Yerukalas, group II-hard working scheduled caste Mala and the Muslims, group III-land owning agricultural castes Reddy and Balija, and group IV-sedentary urban dwelling castes such as Brahmins, Vyshyas, and Marwadis. There was a trend of increase in mean blood pressures and the frequency of hypertensives (SBP ≥160 and/or DBP ≥95) with increasing age in all groups, and the increase was more distinct from group I to group IV. Mean values of body mass index (BMI: weight/height² ) and body fat (SF4: sum of biceps, triceps, subscapular, and suprailiac skinfolds) also showed an increasing trend from group I to group IV. A somewhat opposite trend was evident in two indices of fat distribution, centripetal fat ratio (CFR: ratio of subscapular to the sum of subscapular and triceps skin fold thicknesses) and the relative fat pattern index (RFPI: ratio of subscapular skinfold thickness to the sum of subscapular and suprailiac skinfold thicknesses). Step-wise regression analysis indicated that while one or the other adiposity measures along with one of the age terms significantly contributed to SBP variation among males in the affluent groups III and IV, neither any adiposity measure nor age explain the variation in group I, and only body fat, not age, in group II. A qualitatively similar pattern was observed in females, except that BMI explained a significant amount of variation in SBP in group I, and only age and not any of the adiposity measures, in group IV. Besides age, BMI and fat pattern indices accounted for a significant amount of variation in DBP, while RFPI explained a significant amount of variation in group IV. The amount of variation in SBP explained by the age and adiposity measures increased from the traditional to urbanized groups in males (2.4% to 24.8%) and females (11.4% to 43.6%). A similar trend was observed in case of DBP in both males (0.2% to 15.4%) and females (7.6% to 21.8%). Analysis of covariance of the pooled sample suggested that each of five categorical variables-physical activity, smoking, income, food habit, and group membership-independently explained a significant amount of residual variation in SBP of males, while only food habit and social status did so in females. DBP variation, however, was significantly accounted for by only three of the five (excluding food habit and smoking) categorical variables in males and by none in females. The effect of categorical variables on the residual variation in SBP becomes increasingly significant from the traditional to the urbanized groups in males, while this trend is not consistent in females. Am. J. Hum. Biol. 10:5-21, 1998. © 1998 Wiley-Liss, Inc.

Blood pressure risks factors in healthy postmenopausal women: physical activity and hormone replacement

The prevalence of cardiovascular disease (CVD) increases with advancing age in women, particularly after menopause. CVD risk is lower in physically active women relative to their sedentary peers, but the responsible mechanisms are not well understood. The aims of this study were to test the hypotheses that 1) physically active postmenopausal women demonstrate more favorable blood pressure (BP)-related risk factors for CVD than do sedentary healthy women and 2) women on hormone replacement therapy (HRT) also have more favorable levels of these CVD risk factors. BP-related CVD risk factors were measured in physically active women (n = 18; age 55 +/- 1 yr; n = 8 on HRT) and in healthy less-active controls (n = 34; age 59 +/- 1 yr; n = 17 on HRT). Maximal oxygen consumption was higher in the active group, whereas waist-to-hip ratio and waist circumference were lower (all P < 0.005). The active women demonstrated marginally lower (5-8 mmHg; P < or = 0.10) levels of casual, 24-h, and daytime systolic BP (SBP). They also tended to have lower (P = 0.11) daytime SBP loads (percentage of BP recordings > 140/90 mmHg) and lower daytime and nighttime BP variabilities (P = 0.04) and a reduced (P < 0.007) SBP response to submaximal exercise. Women on HRT tended to have lower (3-4 mmHg; P = 0.07) levels of 24-h and nighttime diastolic BP (DBP) relative to the nonusers and smaller (P < 0.04) daytime and 24-h DBP loads. Stepwise multiple regression indicated that waist circumference was the primary predictor of most of the SBP-related CVD risk factors while HRT use was the best predictor for DBP loads. These findings indicate that, in general, physically active postmenopausal women demonstrate more favorable SBP-related CVD risk factors relative to their less-active healthy peers, which may be mediated, in party, by their lower levels of abdominal adiposity. In addition, HRT use tends to be associated with lower levels of DBP-related CVD risk factors.

Therapeutic challenges in the obese diabetic patient with hypertension

Obesity, diabetes mellitus, and hypertension are common and interrelated medical problems in Westernized, industrialized societies. These medical conditions are associated with an increased risk of cardiovascular disease and are more prevalent among minorities, such as African-American and Hispanic populations. The associated cardiovascular risks of these problems are more thoroughly addressed in another review in this supplement. Obesity markedly enhances the development of type II diabetes. Moreover, it enhances the cardiovascular risk associated with other risk factors, such as hypertension and dyslipidemia. Weight reduction in association with an aerobic exercise program improves metabolic abnormalities and reduces blood pressure in individuals with diabetes and hypertension. Frequently, however, pharmacologic treatment is required to lower blood pressure. Individual therapy with an angiotensin-converting enzyme (ACE) inhibitor is preferred initially in these individuals, with the addition of either a low dose diuretic or a nondihydropyridine calcium antagonist if additional blood pressure reduction is required. These additive agents are recommended, since each has been shown individually to reduce cardiovascular morbidity and to preserve renal function among diabetic patients. Other issues, such as aggressive therapy of lipids and adequate glycemic control, are also important strategies for reducing cardiovascular and renal morbidity and mortality in this very high-risk population.

Correlates of the hemodynamic determinants of blood pressure

The purpose of this study was to investigate the association of sex, race, lean body mass, and fat mass with the hemodynamic determinants of blood pressure, including stroke volume, heart rate, and total peripheral vascular resistance. The study included 201 subjects aged 6 to 17 years, 105 of whom were male and 98 of whom were black. Lean body mass and fat mass were both significant (P < .05) independent determinants of stroke volume, cardiac output, and total peripheral vascular resistance. However, the direction of the effect of lean body mass was opposite for stroke volume and cardiac output compared with that of total peripheral vascular resistance. The direct relationship of lean body mass with systolic blood pressure (SBP) and diastolic blood pressure (DBP) (regression coefficients, 0.55 +/- 0.05 for SBP and 0.47 +/- 0.05 for DBP) indicates that the effect of lean body mass on cardiac output may predominate. Lean body mass explained substantially more of the variance of the hemodynamic variables than did fat mass. After control for the effects of body size, male subjects had higher heart rate and cardiac output, and female subjects had higher vascular resistance. White subjects had higher stroke volume and cardiac output, and black subjects had higher peripheral vascular resistance. This study demonstrates that lean body mass is a more important correlate of the hemodynamic determinants of blood pressure than is fat mass and that sex and race have significant independent relationships with the hemodynamic determinants of blood pressure in children and adolescents.

Body weight, cardiovascular risk factors, and coronary mortality. 15-year follow-up of middle-aged men and women in eastern Finland

BACKGROUND

Body weight is closely related to several known cardiovascular risk factors, but it may also have an independent effect on the risk of coronary heart disease (CHD). In this study, we analyzed the association between body mass index (BMI) and smoking, serum cholesterol, and blood pressure at baseline, as well as how BMI and the other risk factors are related to CHD mortality.

METHODS AND RESULTS

A total of 16 113 men and women aged 30 to 59 years were examined in eastern Finland in either 1972 or 1977. Serum cholesterol and blood pressure had a positive association and smoking had a negative association with BMI. During the 15-year prospective follow-up, mortality from CHD was positively associated with BMI. The BMI-associated risk ratio of CHD mortality, adjusted for age and study year, estimated from the Cox proportional hazards model was 1.04 (per kg/m2) (P < .001) among men. Inclusion of smoking in the model increased the risk ratio for BMI, whereas inclusion of serum cholesterol and blood pressure decreased it. In the model that included age, study year, and all three major cardiovascular risk factors, the BMI-associated risk ratio was 1.03 (P = .027). Among women, the BMI-associated risk ratio of CHD mortality adjusted for age and study year was 1.05 (P = .023) and the multifactorial adjusted risk ratio was 1.03 (P = .151).

CONCLUSIONS

Obesity is an independent risk factor for CHD mortality among men and also contributes to the risk of CHD among women. Part of the BMI-associated risk of CHD mortality is mediated through other known cardiovascular risk factors. By preventing overweight, a substantial part of CHD mortality may be prevented.

Is it possible to derive a reliable estimate of human visceral and subcutaneous abdominal adipose tissue from simple anthropometric measurements?

The aim of the study was to generate equations predicting visceral (VAT) and subcutaneous (SAT) abdominal adipose tissue (AT) from simple anthropometric measurements. Magnetic resonance imaging (MRI) was used to measure VAT and SAT cross-sectional areas at the level of L4 in 49 subjects (19 men and 30 women) with a large range of age and body mass index (BMI). BMI, waist and hip circumferences, waist to hip ratio (WHR), subscapular and paraumbilical skinfolds (i.e., "simple" anthropometric measurements), total body fat content by the isotope-dilution method, and abdominal sagittal diameter by MRI (i.e., "nonsimple" anthropometric measurements) were also measured. Equations to estimate VAT and SAT from age and simple anthropometric measurements (i.e., excluding total body fat and abdominal sagittal diameter) were developed. These equations were then used in 24 subjects (nine men and 15 women) to cross-validate them. The best regression equations, including waist circumference in men and waist circumference and age in women, explained 56% and 68% of VAT variability, respectively. The corresponding standard error of the estimate (SEE) in men was approximately 40% and in women approximately 37% of the mean value of VAT measured by MRI. The best regression equations developed to predict SAT had a higher explained variability (approximately 87% in both men and women) and a lower SEE (< 20% of the mean values of SAT measured by MRI). In men, the equation included BMI and hip circumference, and in women, BMI and age. The inclusion of a higher number of simple anthropometric parameters in the predictive models neither significantly increased the explained variability of VAT or SAT nor significantly decreased the SEE of VAT or SAT. Also, inclusion in the multiple regression analysis of total body fat content and abdominal sagittal diameter did not improve prediction. In the cross-validation study, differences between predicted and observed values of VAT were large, with a tendency to overestimation in both men and women. In contrast, differences between predicted and observed values of SAT were small. We suggest that SAT but not VAT can be estimated from age and simple anthropometric measurements. Direct methods (MRI, computed tomography [CT], or other options) should be used for assessment of VAT.

Effect of lean body mass, fat mass, blood pressure, and sexual maturation on left ventricular mass in children and adolescents. Statistical, biological, and clinical significance

BACKGROUND

Left ventricular hypertrophy has been established as an independent risk factor for the development of cardiovascular morbidity and mortality. It is clear that left ventricular mass increases during childhood and adolescence with body growth. The extent to which other factors, such as obesity, stage of sexual maturation, and level of blood pressure, determine left ventricular mass has been controversial.

METHODS AND RESULTS

The study was a cross-sectional evaluation of the relationship of left ventricular mass determined by echocardiography with lean body mass and fat mass determined by dual-energy x-ray absorptiometry, which is the most valid and reliable method for determination of body composition in children and adolescents. The relationship of left ventricular mass with the stage of sexual maturation and with systolic and diastolic blood pressure was also evaluated. Two hundred one subjects (105 boys, 96 girls; 103 white and 98 black) 6 to 17 years old were studied. Age (r = .72), height (r = .81), weight (r = .84), body surface area (r = .87), sexual maturation (r = .75), lean body mass (r = .86), fat mass (r = .54), systolic BP (r = .58), and diastolic BP (r = .48) were all univariate correlates of left ventricular mass. In a multiple regression analysis, only lean body mass, fat mass, and systolic blood pressure were statistically significant independent correlates of left ventricular mass. Lean body mass alone explained 75% of the variance of left ventricular mass, whereas fat mass and systolic blood pressure explained only 1.5% and 0.5% of the variance, respectively. Lean body mass was the strongest determinant of left ventricular mass in all four race-sex groups.

CONCLUSIONS

This study provides an opportunity to separate the effects on left ventricular mass of lean body mass resulting from linear growth from those of fat mass resulting from obesity. Lean body mass, fat mass, and systolic blood pressure all have a statistically significant independent association with left ventricular mass, suggesting that all three play an important biological role in determining left ventricular mass. However, fat mass and systolic blood pressure have only a small impact on left ventricular mass. This indicates that fat mass and blood pressure would be expected to be of only minor clinical importance in determining left ventricular mass in normal children and adolescents.

Glucose metabolism in abdominally obese hypertensive and normotensive subjects

To determine whether the combination of obesity and hypertension results in additive defects in oxidative and nonoxidative glucose metabolism and the association of these changes with altered hemodynamic actions of insulin, we studied 11 abdominally obese hypertensive, 6 abdominally obese normotensive, and 7 lean normotensive nondiabetic subjects. Endogenous glucose production and glucose metabolized were calculated from a euglycemic clamp at 72 and 287 pmol insulin/m2 per minute. Glucose metabolized divided by insulin was lower at 72 pmol/m2 per minute in both obese groups than in lean normotensive subjects, at 148 +/- 14, 144 +/- 33, and 373 +/- 69 (mumol/m2 per minute)/(pmol/L), respectively (P < .01). Similar results were obtained during the higher insulin dose. Nonoxidative and oxidative glucose disposals by indirect calorimetry were lower in both abdominally obese groups (P < .05). Hepatic glucose production was completely suppressed in lean subjects at the lower insulin dose and in all three groups at the higher insulin dose. Hemodynamic responses during the clamp were not significantly different among the three groups. Abdominal obesity is associated with defects in insulin-regulated oxidative and nonoxidative glucose disposal as well as in insulin suppression of hepatic glucose production. Mild hypertension does not exacerbate these defects. Whereas the global impairment in glucose metabolism suggests the presence of an early defect or defects, including reduced tissue perfusion, systemic and regional hemodynamic responses to insulin were not altered. These findings do not support a direct role for insulin resistance in the pathogenesis of the hypertension associated with abdominal obesity.

Association of body mass index and regional fat distribution with blood pressure investigated by 24-hour ambulatory blood pressure monitoring in android-type obese

In 46 female outpatients with android-type obesity, body mass index (BMI) 36.6 +/- 1.0, waist to hip ratio (WHR) > 0.86, and normal glucose tolerance (NGT) who were hypertensive at entry study [blood pressure (BP) > 140/90 mm Hg] and in 10 clinically healthy, nonobese, normotensive women, we evaluated the relationship between BMI, fat mass, WHR, fasting blood glucose, sum of blood glucose levels during oral glucose tolerance test and casual BP levels, 24-h ambulatory BP monitoring (ABP) parameters as the 24-hour mean, day-time mean, night-time mean and, by using a periodic model of cosine regression, MESOR (midline estimating statistic of rhythm), amplitude, acrophase, and baric impact. In android obese women, a negative correlation between ABP levels (day-/night-time, MESOR, and baric impact of systolic BP; night-time and MESOR of diastolic BP) and BMI has been documented. A positive correlation between systolic BP (casual, night-time mean, MESOR, amplitude, and baric impact), diastolic baric impact, and the WHR has been found. No correlation has been demonstrated between ABP monitoring parameters, and BMI, body fat, and WHR in the control group. Our data could suggest that, when enrolling obese subjects, it must be taken into account that obesity is a heterogeneous disorder. There are in fact obese subjects with normal or impaired glucose tolerance, as well as diabetics with moderate to severe obesity and with gynecoid or android-type obesity. In our android obese subjects with NGT, the WHR rather than the BMI was found to be a better predictor of hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)

Body weight and fat cell size in young men with mild blood pressure elevation

The aim of the study was to assess the relationship between body fat distribution and blood pressure. Forty-four men, aged 19-22 years, with mild blood pressure elevation (MBPE) and 29 normotensive controls (NC) were investigated. Body fat distribution was assessed by calculating fat cell size in biopsy samples of adipose tissue from different subcutaneous depots. The subjects in MBPE group were heavier than those in NC group (79.7 +/- 2.7 and 71.5 +/- 1.6 kg, p < 0.05). Total body fat was also significantly higher in the MBPE group (12.5 +/- 1.6 and 8.1 +/- 1.3 kg, p < 0.05) but not the lean body cell mass (36.8 +/- 1.1 and 34.7 +/- 0.9 kg, n.s.). Fat cell size (microgram/cell) in the lower abdominal area were significantly bigger in MBPE than in NC (respectively 40.9 +/- 4.4 and 28.0 +/- 3.1, p < 0.05). The same differences applied for fat cell size in the upper abdominal (respectively 43.1 +/- 3.0 and 26.8 +/- 3.0, p < 0.001) and averaged abdominal areas (respectively 40.1 +/- 3.4 and 26.8 +/- 2.8; p < 0.05). Fat cell size in gluteal, femoral and averaged gluteofemoral areas did not differ between MBPE and NC. Therefore, the abdominal/gluteofemoral ratio was significantly higher in MBPE than in NC (respectively 1.1 +/- 0.1 and 0.7 +/- 0.1; p < 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Relation between weight and body fat's distribution and ambulatory blood pressure in Chinese elderly

Ninety-five subjects aged 60 years and over underwent casual and ambulatory blood pressure (BP) measurements as well as weight, height, both waist and hip circumferences and both upper arm and thigh circumferences. Most anthropometric variables were significantly correlated with measures of BP. One stepwise regression analysis was applied to reveal that among measures of BP, 24-hour systolic BP had the strongest correlation with waist/hip ratio and awaking diastolic BP the strongest correlation with weight, both waist and hip circumferences and body mass index. Another was used to show that waist/hip ratio was the best overall predictor of systolic BP and weight the best overall predictor of diastolic BP. We suggest that (1) ambulatory BP be superior to casual BP in evaluating effect of weight and body fat's distribution on BP and (2) waist/hip ratio more important than weight in the hypertensive target organ damage and the prognosis of hypertension in Chinese elderly population.

The association of waist/hip ratio with diabetes complications in an adult IDDM population

Cross-sectional data from the Epidemiology of Diabetes Complications Study were used to examine the relationships between waist to hip circumference ratio (WHR) and the presence of diabetes complications in IDDM adults ages 18-45 years (N = 586). Significantly higher WHRs were observed among both genders with proliferative retinopathy or peripheral vascular disease and only among males with either neuropathy or nephropathy compared to those free of these complications. Logistic regression to determine the strength of association between WHR and each complication demonstrated that although WHR was significantly related to each complication (except nephropathy among females), WHR was only independently related to neuropathy in males and PVD in females in the final model when hypertension, LDL- and HDL-cholesterol and fibrinogen were included. These findings suggest that WHR acts as a marker of risk for diabetes complications mainly through an influence on other complication risk factors.

Correlates of blood pressure in Seventh-Day Adventist (SDA) and non-SDA adolescents

OBJECTIVE

This comparative study was designed to discover early determinants of systolic (S) and diastolic (D) blood pressure (BP) elevations in 138 Seventh-Day Adventist (SDA) and 89 non-SDA male and female adolescents (median age, 17 years) living at three residential secondary schools in North Carolina.

METHODS

Measurements were made of blood pressure, body weight, and height, and information was collected on lifestyle factors, dietary intake, and other behaviors, including exercise, religiosity, Type A behavior, and anger, by questionnaire. Multiple stepwise regression analyses were performed with BP, either SBP or DBP, as the independent variable.

RESULTS

A significant direct association was found only between body weight and BP, but weak associations were shown between BP and other variables, including exercise, diet, religiosity, Type A behavior, and anger. Male and female SDA students showed significantly higher SBPs and DBPs than did non-SDA adolescents though the differences were small (approximately 5 mm for each sex).

CONCLUSIONS

These findings suggest that the higher BP values of SDA adolescents, who were all practicing lacto-ovo-vegetarians, compared to similarly aged health-conscious non-SDAs, are determined more by eating behaviors that contribute to gains in body weight than by any other lifestyle variable. Furthermore, these data support the notion that the BP-protective effects of the vegetarian diet may not emerge in these SDA youth until early adulthood.

Indices of obesity and body fat distribution in arteriographically defined coronary artery disease in men

Anthropometric measurements descriptive of obesity, body fat distribution and body build were made in 186 males undergoing diagnostic coronary arteriography. Using stepwise multiple logistic regression analysis, two indices of body fat distribution were independently associated with coronary disease, while the widely used indices of obesity, namely body mass index and percentage body fat, were not. A significant association with disease was found for the ratio of waist to thigh circumferences (waist/thigh ratio), which emerged in the first step of the multivariate model (p < 0.005). The ratio of waist to hip circumferences (waist/hip ratio), a widely used index of body fat distribution, was found to have a negative association with disease (p < 0.05). This study suggests that use of body fat distribution indices may assist in the assessment of the risk factor profile of cardiac patients.

Relationship between insulin resistance and coronary heart disease in diabetes mellitus and the general population: a critical appraisal

The hypothesis that a causal relationship exists between insulin resistance and atherogenesis was first proposed over 23 years ago, and has given rise to a vast literature. Biological plausibility has been lent to the hypothesis by studies in which insulin has produced some effects in cell and tissue culture, and in vivo in arterial tissue, consistent with our understanding of the pathogenesis of atherosclerosis. Clinical studies demonstrating a complex interrelationship between insulin resistance-hyperinsulinaemia and established risk factors for CHD--hypertension, hypertriglyceridaemia, low HDL cholesterol levels and abdominal obesity--are reviewed. A review of the studies examining an independent association between hyperinsulinaemia and coronary heart disease is presented. Cross-sectional studies in both the general population and diabetes support the relationship; however, prospective studies in the general population provide limited and inconsistent support for this hypothesis and highlight the confounding effects of blood pressure, dyslipidaemia and obesity on the effects of hyperinsulinaemia. In subjects with NIDDM and impaired glucose tolerance, prospective studies have not shown a deleterious effect of insulin treatment per se, nor have they consistently shown a significantly increased risk for those with higher endogenous insulin levels. The therapeutic implications of the evidence to date are less complex and involve weight reduction by diet and exercise, the lowering of elevated blood pressure with metabolically neutral agents, the judicious use of lipid lowering drugs and, in diabetes, the use of insulin where clinically indicated.

Toward a definition of a successful dieter

The purpose of the research was to examine the characteristics of successful weight losers and to compare the findings with a control group of unsuccessful weight losers. The project was designed around a definition of successful dieters, based on the Metropolitan Life Insurance weight tables. The definition, in fact, was not particularly useful. This article describes the difficulties associated with using the original definition as the inclusion criteria for sample selection, the reanalysis of data using the Body Mass Index (BMI), and finally, the creation of a new definition developed from the construction of weight history based on changes in the BMI as an adult. This article presents the final outcome of what a definition of a successful dieter should consist in future research.

The role of diet in the genesis and treatment of hypertension

In this brief review, we have not been able to address all of the various dietary factors which have been implicated as causal in hypertension. Because of the heterogeneity of hypertension, it is quite difficult to find a simple answer to the question of how important dietary factors are in causing hypertension and even more difficult to answer the question of how diet should be therapeutically altered in treating a hypertensive patient. Given the difficulties in achieving good compliance to almost any dietary prescription and the lifestyle changes these therapies often require, significant benefit must be demonstrated to justify the efforts. It is worth emphasizing that many of the dietary alterations which have been proposed for treating hypertension have even better established preventative health rationales which justify their use. Although salt intake is a factor in the genesis of hypertension, the effectiveness of salt restriction varies between patients. Despite the absence of good predictors of response, moderate sodium reduction is a reasonable first step when dealing with a hypertensive patient. In obese hypertensive patients, weight loss provides a modest but significant BP reduction. Added benefit may be obtained by lowering total fat content and increasing the ratio of polyunsaturated to saturated fats. The reduction in cardiovascular risk with these changes in dietary fat, over and above the lowering of BP, make this approach appropriate in all hypertensive patients. Potassium supplementation, while sometimes effective, is more difficult to recommend broadly. Calcium supplementation is certainly reasonable in women, for whom such therapy should be seen as good dietary advice for the prevention of osteoporosis. Moderate alcohol intake probably has little deleterious effect, whereas heavy alcoholism does contribute to increased BP. Again, reduction of alcohol intake is important for reasons other than the modest BP reduction attained.

A review of the association between abdominal fat distribution, health outcome measures, and modifiable risk factors

PURPOSE OF THE REVIEW. This review of the literature examines the relationship between abdominal fat distribution and specific health outcome measures, modifiable risk factors, the impact of intervention efforts, and the significance of measurement methods. SEARCH METHODS USED. The research material that was received was found through several on-line data bases, including MEDLINE and CINAHL, an examination of references from selected articles, a manual review of recent relevant journals, and interviews with several physicians and epidemiologists who are experts in this field of inquiry. Forty-three research articles were reviewed for the section on health risk outcomes and abdominal fat distribution. Twenty studies were reviewed in the section on modifiable variables associated with fat distribution. Finally, 10 studies which examined the effect of behavior change on fat distribution were included in this review. SUMMARY OF IMPORTANT FINDINGS. Recent research indicates that people whose body fat is deposited more in the central or abdominal area, especially the intra-abdominal area, than it is in the gluteofemoral area are at increased risk for cardiovascular disease. This risk is independent of, but exacerbated by, the degree of obesity. Several nonmodifiable factors such as age, gender, and menopause as well as some modifiable factors such as obesity, smoking, physical inactivity, and alcohol intake are positively associated with abdominal fat deposition. MAJOR CONCLUSIONS. Intervention results indicate that it is possible to decrease abdominal fat with total weight loss or smoking cessation.

Genetic and environmental covariance of serum cholesterol and blood pressure in female twins

Blood pressure elevation is frequently associated with elevated cholesterol, triglyceride or low density lipoprotein (LDL-C) or low high density lipoprotein (HDL-C). The relative importance of genetic and environmental factors in these associations is unclear. We examined the relative contribution of genetic and environmental influences to the association between blood pressure and serum lipids in 75 pairs of female twins using path analysis and maximum-likelihood model fitting. Associations between systolic blood pressure and total cholesterol (r = 0.44, P < 0.001), and LDL-C (r = 0.38, P < 0.001), but not HDL-C (r = 0.05, N.S.), remained significant after age and body mass index adjustment. Univariate models suggested genetic effects contributed 60-70% to the variance of total cholesterol, LDL-C, HDL-C and systolic blood pressure. The remaining variance was explained by age and/or unique environmental influences. Using bivariate models, we demonstrated genetic (P = 0.017) and unique environmental covariance (P = 0.011) of cholesterol and systolic blood pressure. Significant genetic covariance (P = 0.038) was observed between LDL-C and systolic blood pressure. The association between blood pressure and total cholesterol in these twins results from shared genetic and similar unique environmental influences. The association between LDL-C and blood pressure is partly due to shared genetic influences. We conclude that both additive genetic and environmental factors unique to the individual are important determinants of the relationships between serum lipids and blood pressure.

Subscapular and triceps skinfold thicknesses, body mass index and cardiovascular risk factors in a cohort of middle-aged employed men

Associations of indices of adiposity with cardiovascular risk factors were examined in 1860 middle aged men employed by the Western Electric Company in Chicago in 1960 and 1961. Body mass index and subscapular and triceps skinfolds were examined for associations with systolic and diastolic blood pressure, serum cholesterol, and post-load serum glucose. Correlations of study variables measured one year apart suggest that triceps and subscapular skinfold measurements are less reproducible than body mass index, but more reproducible than measurements of systolic and diastolic blood pressure and serum cholesterol. Associations with blood pressure were stronger for body mass index than for skinfolds, and subscapular skinfold was associated with blood pressure independently of triceps skinfold, as well as age, heart rate, alcohol intake, and family history of cardiovascular disease. Body mass index was also generally more strongly related to serum cholesterol than skinfold measurements. Triceps skinfold was more strongly related to serum cholesterol than subscapular skinfold based on average values for the variables in 1960-61, but subscapular skinfold was more strongly related to one-year change in serum cholesterol. Subscapular skinfold was as strongly related to serum glucose as body mass index. This association was also independent of triceps skinfold and other variables. These analyses demonstrate positive associations of subscapular skinfold, an index of central adiposity, with blood pressure and serum glucose levels. Associations of subscapular and triceps skinfolds with serum cholesterol levels were not consistent in the cross-sectional and longitudinal analyses and require further investigation.

Long-term morbidity and mortality of overweight adolescents. A follow-up of the Harvard Growth Study of 1922 to 1935

BACKGROUND

Overweight in adults is associated with increased morbidity and mortality. In contrast, the long-term effect of overweight in adolescence on morbidity and mortality is not known.

METHODS

We studied the relation between overweight and morbidity and mortality in 508 lean or overweight adolescents 13 to 18 years old who participated in the Harvard Growth Study of 1922 to 1935. Overweight adolescents were defined as those with a body-mass index that on two occasions was greater than the 75th percentile in subjects of the same age and sex in a large national survey. Lean adolescents were defined as those with a body-mass index between the 25th and 50th percentiles. Subjects who were still alive were interviewed in 1988 to obtain information about their medical history, weight, functional capacity, and other risk factors. For those who had died, information on the cause of death was obtained from death certificates.

RESULTS

Overweight in adolescent subjects was associated with an increased risk of mortality from all causes and disease-specific mortality among men, but not among women. The relative risks among men were 1.8 (95 percent confidence interval, 1.2 to 2.7; P = 0.004) for mortality from all causes and 2.3 (95 percent confidence interval, 1.4 to 4.1; P = 0.002) for mortality from coronary heart disease. The risk of morbidity from coronary heart disease and atherosclerosis was increased among men and women who had been overweight in adolescence. The risk of colorectal cancer and gout was increased among men and the risk of arthritis was increased among women who had been overweight in adolescence. Overweight in adolescence was a more powerful predictor of these risks than overweight in adulthood.

CONCLUSIONS

Overweight in adolescence predicted a broad range of adverse health effects that were independent of adult weight after 55 years of follow-up.