Regional obesity and risk of cardiovascular disease; the Framingham Study

Fat depot origin affects adipogenesis in primary cultured and cloned human preadipocytes

Fat distribution varies among individuals with similar body fat content. Innate differences in adipose cell characteristics may contribute because lipid accumulation and lipogenic enzyme activities vary among preadipocytes cultured from different fat depots. We determined expression of the adipogenic transcription factors peroxisome proliferator activated receptor-gamma (PPAR-gamma) and CCAAT/enhancer binding protein-alpha (C/EBP-alpha) and their targets in abdominal subcutaneous, mesenteric, and omental preadipocytes cultured in parallel from obese subjects. Subcutaneous preadipocytes, which had the highest lipid accumulation, glycerol-3-phosphate dehydrogenase (G3PD) activity, and adipocyte fatty acid binding protein (aP2) abundance, had highest PPAR-gamma and C/EBP-alpha expression. Levels were intermediate in mesenteric and lowest in omental preadipocytes. Overexpression of C/EBP-alpha in transfected omental preadipocytes enhanced differentiation. The proportion of differentiated cells in colonies derived from single subcutaneous preadipocytes was higher than in mesenteric or omental clones. Only cells that acquired lipid inclusions exhibited C/EBP-alpha upregulation, irrespective of depot origin. Thus regional variation in adipogenesis depends on differences at the level of transcription factor expression and is a trait conferred on daughter cells.

Differential effects of oral estrogen versus oral estrogen-androgen replacement therapy on body composition in postmenopausal women

Menopause is associated with decreased lean body mass and increased fat due to aging and declining hormone secretion. Estrogens or estrogen-progestins have been used to alleviate vasomotor symptoms. However, estrogen-androgen (E/A) therapy is also used for vasomotor symptom relief and has been shown to increase lean body mass while decreasing fat mass. The objective of this 16-wk, double-blind, randomized, parallel group clinical trial was to compare esterified estrogen plus methyltestosterone (1.25 mg estrogen + 2.5 mg methyltestosterone/d; E/A group) vs. esterified estrogen alone (1.25 mg/d; E group) on body composition. Forty postmenopausal women (mean age, 57 yr) participated. Compared with estrogen treatment alone, women in the E/A group increased their total lean body mass and reduced their percentage fat for all body parts (P < 0.05). After E/A treatment, there were statistically significant increases in lean body mass by 1.232 kg [0.181 +/- 0.004, 0.81 +/- 0.057, and 0.24 +/- 0.009 kg in the upper body (P = 0.021), trunk (P = 0.001), and lower body (P = 0.047), respectively]. In the E group, the increase was 0.31 +/- 0.004, 0.021 +/- 0.03, and 0.056 +/- 0.05 kg in the upper body, trunk, and lower body, respectively. In the E/A group, body fat was reduced by 0.90 kg (P = 0.18 for the trunk only), and percentage body fat declined by 7.4% (P < or = 0.05 for all body parts). Lower body strength increased by 23.1 kg (51 lb) in the E/A group vs. only 11 kg (24.25 lb) in the E group (P = 0.002 between groups). A statistically significant increase in weight (2.7 +/- 5.1 vs. 0.1 +/- 4.6 lb; P < 0.05) was observed in the E/A group compared with the E group. When subjects were given self-reporting questionnaires, more improvement was noted in sexual functioning and quality of life in the E/A group when compared with patients receiving E alone. There were no noteworthy side effects. In conclusion, E/A replacement therapy can improve body composition, lower-body muscle strength, quality of life, and sexual functioning in postmenopausal women.

Body mass index and waist circumference independently contribute to the prediction of nonabdominal, abdominal subcutaneous, and visceral fat

BACKGROUND

It is unknown whether the ability of waist circumference (WC) to predict health risk beyond that predicted by body mass index (BMI) alone is explained in part by the ability of WC to identify those with elevated concentrations of total or abdominal fat.

OBJECTIVE

We sought to determine whether BMI and WC independently contribute to the prediction of non-abdominal (total fat - abdominal fat), abdominal subcutaneous, and visceral fat.

DESIGN

Fat distribution was measured by magnetic resonance imaging in 341 white men and women. Multiple regression analysis was performed to measure whether the combination of BMI and WC explained a greater variance in non-abdominal, abdominal subcutaneous, and visceral fat than did BMI or WC alone. These fat depots were also compared after a subdivision of the cohort into 3 BMI (normal, overweight, and class I obese) and 3 WC (low, intermediate, and high) categories according to the classification system used to identify associations between BMI, WC, and health risk.

RESULTS

Independent of age and sex, the combination of BMI and WC explained a greater variance in non-abdominal, abdominal subcutaneous, and visceral fat than did either BMI or WC alone (P < 0.05). For non-abdominal and abdominal subcutaneous fat, BMI was the strongest correlate; thus, by adding BMI to WC, the variance accrued was greater than when WC was added to BMI. However, when WC was added to BMI, the added variance explained for visceral fat was greater than when BMI was added to WC. Furthermore, within each of the 3 BMI categories studied, an increase in the WC category was associated with an increase in visceral fat (P < 0.05).

CONCLUSIONS

BMI and WC independently contribute to the prediction of non-abdominal, abdominal subcutaneous, and visceral fat in white men and women. These observations reinforce the importance of using both BMI and WC in clinical practice.

Trunk fat and blood pressure in children through puberty

BACKGROUND

Fat distribution is well recognized as a cardiovascular risk factor in adults. The association between android fat distribution and cardiovascular risk factors, such as blood pressure (BP), was previously reported in an African-American and Caucasian pediatric population. The aim of the present study was to investigate the relationship between BP and body fat distribution in a large cross-sectional pediatric sample. The effects of race, sex, and puberty on this relationship were assessed.

METHODS AND RESULTS

BP was measured in 920 healthy children and adolescents (African-American, Asian, and Caucasian, ages 5 to 18 years). Fat distribution was determined by skinfold thickness and dual-energy X-ray absorptiometry (DXA). Pubertal status was assessed by the criteria of Tanner. Regression analysis was used to explore the association between BP and fat distribution. Significant positive relationships between systolic and diastolic BP and trunk fat adjusted for total fat were seen in boys at all pubertal stages in all 3 races by both DXA and skinfold measurements. In girls, trunk fat was not a significant predictor of BP.

CONCLUSIONS

Our results demonstrate a sex difference in the relationship between BP and trunk fat in that a significant positive relationship was present in boys only. These findings, based on 2 independent measures of fat distribution, may help identify the specific features of individuals at risk, allow earlier intervention, and suggest sex-specific determinants for BP.

Regional differences in the response of human pre-adipocytes to PPARgamma and RXRalpha agonists

We have previously reported that omental (OM) preadipocytes respond less well to the prodifferentiating effects of thiazolidinediones than do preadipocytes from subcutaneous (SC) depots. This finding is consistent with in vivo alterations in fat distribution that occur in humans treated with thiazolidinediones. To explore these site-related differences further, we used real-time RT-PCR to quantify the specific mRNAs encoding peroxisome proliferator-activated receptor (PPAR) gamma1 and gamma2 and found that both isoforms were more highly expressed in SC than in OM preadipocytes. After 10 days of thiazolidinedione treatment, preadipocytes from both depots showed a small and comparable increase in expression of PPARgamma1 mRNA (1.7 +/- 0.2-fold [P = 0.007]) and 1.3 +/- 0.1-fold [P = 0.008] increase for SC and OM, respectively). There was a much larger increase in PPARgamma2 expression, which was significantly greater in SC compared with OM preadipocytes (11.1 +/- 2.8-fold [P = 0.0003] and 5.5 +/- 1.7-fold [P = 0.0003], respectively; P = 0.014 for SC versus OM). To establish whether the refractoriness of OM preadipocytes to differentiation was unique to activators of the PPARgamma pathway, we examined the effects of the retinoid X receptor (RXR) ligand LG100268. As assessed by glycerol-3-phosphate dehydrogenase activity, LG100268 had a greater effect on the differentiation of SC compared with OM preadipocytes when examined alone (SC = 5.7 +/- 1.7-fold vs. OM = 1.9 +/- 0.6-fold; P < 0.05) or in combination with rosiglitazone (SC = 27.0 +/- 7.5 vs. OM = 10.6 +/- 3.6-fold; P < 0.05). Consistent with this, RXRalpha mRNA levels were also higher in SC than in OM preadipocytes. In summary, the previously reported insensitivity of OM preadipocytes to the differentiating effects of thiazolidinediones may relate to their lower basal levels of PPARgamma1 and gamma2 mRNA and their diminished capacity to upregulate PPARgamma2 expression in response to ligand. That omentally derived cells also show reduced responsiveness to the prodifferentiating actions of an RXR ligand and a lower expression of RXRalpha in the undifferentiated state suggests that they may have a more generalized resistance to differentiation.

Relationship between reduced serum IGF-I levels and accumulation of visceral fat in Japanese men

OBJECTIVE

To investigate whether the changes in IGF-I concentrations after weight reduction in Japanese overweight men are associated with changes in visceral and subcutaneous fat.

DESIGN

Cross-sectional and longitudinal clinical intervention study with exercise education.

SUBJECTS

One-hundred and twelve Japanese overweight men aged 30-59 y (body mass index (BMI) 28.4+/-2.5 kg/m(2)) and 33 normal-weight men aged 30-39 y (BMI 22.1+/-1.5 kg/m(2)) at baseline. From the participants, 56 randomly selected overweight men (BMI 28.8+/-2.8) were further enrolled into a 1 y exercise program.

MEASUREMENTS

Fat distribution was evaluated by visceral fat (V) and subcutaneous fat (S) areas measured with computed tomography scanning at umbilical levels, metabolic parameters and hormones including insulin, leptin and IGF-I at baseline and after 1 y.

RESULTS

In 112 overweight subjects at baseline, insulin (10.5+/-5.0 microU/ml) and leptin (6.4+/-3.7 ng/ml) significantly correlated with both V (r=0.260, P=0.0073; r=0.410, P<0.0001) and S areas (r=0.377, P<0.0001; r=0.613, P<0.0001), respectively. IGF-I (156.8+/-48.7 microU/ml) significantly and negatively correlated with V area (r=-0.242, P=0.0125) and age (r=-0.192, P=0.0480). In normal-weight men aged 30-39 y (n=33) and age-matched subjects (n=30) selected from the 112 overweight men, the serum IGF-I further tightly correlated with V area (r=-0.467, P<0.0001). Visceral fat area and age were independently related to serum IGF-I levels by multiple regression analysis. By intervention with exercise education, 56 overweight subjects showed an increase in daily steps (6224+/-2781 to 7898+/-4141 steps/day) and reduction of BMI (28.8+/-2.8 to 27.7+/-2.9). deltaIGF-I significantly correlated with deltaV area (r=-0.432, P=0.0009) but not with DeltaS area or deltaBMI.

CONCLUSION

The present study indicated a negative correlation between IGF-I levels and visceral fat at baseline as well as an association between the reduction in visceral fat and increase in IGF-I levels after an exercise intervention.

The case for more active policy attention to health promotion

Until recently, when anthrax triggered a concern about preparedness in the public health infrastructure, U.S. health policy and health spending had been dominated by a focus on payment for medical treatment. The fact that many of the conditions driving the need for treatment are preventable ought to draw attention to policy opportunities for promoting health. Following a brief review of the determinants of population health-genetic predispositions, social circumstances, environmental conditions, behavioral patterns, and medical care-this paper explores some of the factors inhibiting policy attention and resource commitment to the nonmedical determinants of population health and suggests approaches for sharpening the public policy focus to encourage disease prevention and health promotion.

Tracking body fat distribution during growth: using measurements at two occasions vs one

OBJECTIVE

To investigate whether within-individual variation is a factor in the generally reported poor tracking of central body fat distribution (CBFD) during development and whether two measurements of CBFD during each measurement occasion would improve the estimate of tracking over time.

METHODS

A longitudinal study compared the results of two measurements of body fat (BF) and CBFD during each measurement occasion to the results of one measurement of BF and CBFD during each occasion every 4 months over 1-3 y. A total of 345 boys and 333 girls in three age cohorts of 8, 11 and 14 y at baseline were examined. BF variables were: body mass index (BMI); fat mass and percentage body fat from bioelectrical impedance; two skinfold sums; and abdominal circumference. CBFD variables were: waist/hip and waist/thigh ratios; conicity; and log upper-lower skinfold ratio.

RESULTS

Three-year tracking of BF varied from 0.79 to 0.90 for one- and from 0.81 to 0.93 for two-occasion measurements showing no apparent sex- or cohort-effects. Three-year tracking of CBFD was lower than that of BF (0.68-0.75), but improved significantly with two-occasion measurements (0.75-0.82).

CONCLUSIONS

Within-individual variation is a significant factor in reported low tracking of CBFD in childhood. Estimates of tracking currently in the literature may underestimate the predictive value of CBFD, possibly because this research has used one-occasion measurement. The increased use of two-occasion measurement should significantly improve the tracking of CBFD during development and provide a more realistic understanding of its predictive value.

Association between simple anthropometric indices and cardiovascular risk factors

OBJECTIVE

To identify which of the three simple anthropometric indices, body mass index (BMI), waist-to-hip ratio (WHR) and waist circumference (WC), best predicts cardiovascular risk factors, and to determine if the association between the anthropometric indices and cardiovascular risk factors varies with gender.

DESIGN AND METHODOLOGY

A cross-sectional population-based survey was carried out during 1995-1996. One thousand and ten Chinese people (500 men and 510 women) aged 25-74 y were recruited as subjects for the study. Metabolic profiles and anthropometric indices were measured.

RESULTS

Partial correlation and co-variance analyses showed that WC exhibited the highest degree of association with almost all of the studied metabolic profiles for both men and women. We observed significant gender differences in the association between central or general obesity with cardiovascular risk factors. BMI had an independent and significant association with metabolic risks in men, but not in women, whereas WHR was more strongly correlated with metabolic risks for women than for men. Logistic regression analysis further confirmed the magnitude of the association between the obesity indices and metabolic risks. Among the studied metabolic variables, serum insulin showed the highest degree of association with the obesity indices, followed by plasma glucose, triglyceride, HDL and blood pressure. Total cholesterol and LDL-cholesterol had a small but significant correlation with obesity. No threshold values in the relation between either the anthropometric indices and metabolic values, or with hypertension, diabetes and dislipidemia were observed.

CONCLUSION

The association of central or general obesity and metabolic syndrome varied with gender. In addition, the useful anthropometric predictors for cardiovascular risk factors were BMI and WC for men, and WC and WHR for women.

Treatment of the elderly post-myocardial infarction patient

Coronary risk factors should be modified in older persons after myocardial infarction (MI). Aspirin 160-325 mg daily and beta blockers should be administered indefinitely. Anticoagulants should be administered post-MI to patients unable to tolerate daily aspirin, to those with persistent atrial fibrillation, and to those with left ventricular thrombus. Nitrates, along with beta blockers, should be used to treat angina pectoris. Angiotensin-converting enzyme inhibitors should be administered after MI to patients who have congestive heart failure, an anterior MI, or a left ventricular ejection fraction of at or below 40%. There are no class I indications for the use of calcium channel blockers after MI. Complex ventricular arrhythmias should be treated with beta blockers. Persons with life-threatening ventricular tachycardia or ventricular fibrillation or who are at very high risk for sudden cardiac death after MI should receive an automatic implantable cardioverter-defibrillator. There are no class I indications for the use of hormonal therapy in postmenopausal women after MI. Indications for coronary revascularization after MI in older individuals are prolongation of life and relief of unacceptable symptoms despite optimal medical management.

Obesity and sarcopenia after menopause are reversed by sex hormone replacement therapy

OBJECTIVE

Menopause is linked to an increase in fat mass and a decrease in lean mass exceeding age-related changes, possibly related to reduced output of ovarian steroids. In this study we examined the effect of combined postmenopausal hormone replacement therapy (HRT) on the total and regional distribution of fat and lean body mass.

RESEARCH METHODS AND PROCEDURES

Sixteen healthy postmenopausal women (age: 55 +/- 3 years) were studied in a placebo-controlled, crossover study and were randomized to 17beta estradiol plus cyclic norethisterone acetate (HRT) or placebo in two 12-week periods separated by a 3-month washout. Total and regional body composition was measured by DXA at baseline and in the 10th treatment week in both periods. Changes were compared by a paired Student's t test.

RESULTS

The change in body weight during HRT was equal to the change during placebo (-24.6 g vs. -164 g, p = 0.42), but relative fat mass was significantly reduced (-0.5% vs. +1.24%, p < 0.01). During HRT, compared with during placebo, lean body mass increased (+347 g vs. -996 g, p < 0.01) and total fat mass decreased (-400 g vs. +836 g, p = 0.06). Total bone mineral content increased (+28.9 g vs. -4.4 g, p = 0.04) and abdominal fat decreased (-185 g vs. +253 g, p = 0.04) during HRT compared with placebo.

DISCUSSION

HRT is linked to the reversal of both menopause-related obesity and loss of lean mass, without overall change in body weight. The increase in lean body mass during HRT is likely explained by muscle anabolism, which in turn, prevents disease in the elderly.

Effects of sibutramine on body weight and serum lipids: a double-blind, randomized, placebo-controlled study in 322 overweight and obese patients with dyslipidemia

BACKGROUND

Cardiovascular risk factors associated with obesity, including dyslipidemia, can be improved by weight loss. The main dyslipidemia associated with obesity is elevated serum triglyceride and decreased serum high-density lipoprotein cholesterol (HDL-C) levels.

METHODS

A total of 322 obese patients (body mass index > or = 27) with serum triglyceride levels > or = 250 mg/dL and < or = 1000 mg/dL and serum HDL-C levels < or = 45 mg/dL (women) and < or = 40 mg/dL (men) were placed on a step I American Heart Association diet and subsequently randomized to sibutramine 20 mg (n = 162) or placebo (n = 160) once daily for 24 weeks.

RESULTS

Patients taking sibutramine had significantly greater mean weight loss than those receiving placebo (-4.9 kg vs -0.6 kg, P < or = .05). Forty-two percent of the sibutramine group lost > or = 5% of baseline weight and 12% lost > or = 10% compared with 8% and 3%, respectively, of the placebo group (P < or = .05). Mean decreases in serum triglyceride levels among 5% and 10% weight-loss responders in the sibutramine group were 33.4 mg/dL and 72.3 mg/dL, respectively, compared with an increase of 31.7 mg/dL among all patients receiving placebo (P < or = .05). Mean increases in serum HDL-C levels for 5% and 10% weight-loss responders in the sibutramine group were 4.9 mg/dL and 6.7 mg/dL, respectively, compared with an increase of 1.7 mg/dL among all patients in the placebo group (P < or = .05). Adverse events and discontinuation rates were similar in the sibutramine and placebo groups, although sibutramine-treated patients had mean increases in systolic and diastolic blood pressure of 2 to 3 mm Hg relative to placebo.

CONCLUSIONS

In overweight and obese patients with high serum triglyceride levels and low serum HDL-C levels, treatment with sibutramine was associated with significant improvements in body weight and in serum triglyceride and HDL-C levels.

Temporal trends in BMI among adults with diabetes

OBJECTIVE

Increasing obesity within the general population has been accompanied by rising rates of diabetes. The extent to which obesity has increased among people with diabetes is unknown, as are the potential consequences for diabetes outcomes.

RESEARCH DESIGN AND METHODS

Community medical records (hospital and ambulatory) of all Rochester, Minnesota, residents aged > or =30 years who first met standardized research criteria for diabetes from 1970 to 1989 (n = 1,306) were reviewed to obtain data on BMI and related characteristics as of the diabetes identification date (+/-3 months). Vital status as of 31 December 1999 and date of death for those who died were obtained from medical records, State of Minnesota death tapes, and active follow-up.

RESULTS

As of the identification date, data on BMI were available for 1,290 cases. Of the 272 who first met diabetes criteria in 1970-1974, 33% were obese (BMI > or =30), including 5% who were extremely obese (BMI > or =40). These proportions increased to 49% (P < 0.001) and 9% (P = 0.012), respectively, for the 426 residents who first met diabetes criteria in 1985-1989. BMI increased significantly with increasing calendar year of diabetes identification in multivariable regression analysis. Analysis of survival revealed an increased hazard of mortality for BMI > or =41, relative to BMI of 23-25 (hazard ratio 1.60, 95% CI 1.09-2.34, P = 0.016).

CONCLUSIONS

The prevalence of obesity and extreme obesity among individuals at the time they first met criteria for diabetes has increased over time. This is disturbing in light of the finding that diabetic individuals who are extremely obese are at increased risk of mortality compared with their nonobese diabetic counterparts.

Biomarkers in disease and health

Biomarkers have considerable potential in aiding the understanding of the relationship between diet and disease or health. However, to assess the role, relevance and importance of biomarkers on a case by case basis it is essential to understand and prioritise the principal diet and health issues. In the majority of cases, dietary compounds are only weakly biologically active in the short term, have multiple targets and can be both beneficial and deleterious. This poses particular problems in determining the net effect of types of foods on health. In principle, a biomarker should be able to contribute to this debate by allowing the measurement of exposure and by acting as an indicator either of a deleterious or of an enhanced health effect prior to the final outcome. In this review, the examples chosen - cancer (stomach, colon/rectal, breast); coronary heart disease and osteoporosis - reflect three major diet-related disease issues. In each case the onset of the disease has a genetic determinant which may be exacerbated or delayed by diet. Perhaps the most important factor is that in each case the disease, once manifest, is difficult to influence in a positive way by diet alone. This then suggests that the emphasis for biomarker studies should focus on predictive biomarkers which can be used to help in the development of dietary strategies which will minimise the risk and be of greater benefit.

Body fat distribution, obesity, overweight and stroke incidence in women and men: the NHANES I Epidemiologic Follow-up Study

OBJECTIVE

To test the hypothesis that an elevated ratio of subscapular to triceps skinfold thickness (SFR), a measure of truncal obesity, is associated with increased incidence of stroke independent of overweight.

DESIGN

Data from the NHANES I Epidemiologic Follow-up Study were analyzed.

SUBJECTS

A cohort of 3652 women and 3284 men with complete data who had no history of stroke at baseline in 1971-1975.

MEASUREMENTS

Incidence of stroke diagnosed at hospital discharge or death during the follow-up period through 1992; triceps and subscapular skinfold thickness (SSF) and body mass index (BMI) at baseline.

RESULTS

In a complex relationship, higher SFR was associated with a mildly but significantly increased incidence of stroke only in white male former smokers. In white men, SSF showed a U-shaped association with stroke risk. In white men, stroke risk was elevated in the top quartile of BMI only in never smokers. In black women, stroke risk was significantly elevated in the bottom compared to the top quartile of BMI. No significant associations were seen in white women or black men.

CONCLUSIONS

In white men, SSF showed a U-shaped association with stroke risk, which was elevated in the top quartile of BMI only in never smokers. Surprisingly, stroke risk was elevated in black women with the lowest BMI. More studies of these associations are needed, especially in black women.

Fat depot origin affects fatty acid handling in cultured rat and human preadipocytes

Regional differences in free fatty acid (FFA) handling contribute to diseases associated with particular fat distributions. As cultured rat preadipocytes became differentiated, FFA transfer into preadipocytes increased and was more rapid in single perirenal than in epididymal cells matched for lipid content. Uptake by human omental preadipocytes was greater than uptake by abdominal subcutaneous preadipocytes. Adipose-specific fatty acid binding protein (aP2) and keratinocyte lipid binding protein abundance was higher in differentiated rat perirenal than in epididymal preadipocytes. This interdepot difference in preadipocyte aP2 expression was reflected in fat tissue in older animals. Carnitine palmitoyltransferase 1 activity increased during differentiation and was higher in perirenal than in epididymal preadipocytes, particularly the muscle isoform. Long-chain acyl-CoA levels were higher in perirenal than in epididymal preadipocytes and isolated fat cells. These data are consistent with interdepot differences in fatty acid flux ensuing from differences in fatty acid binding proteins and enzymes of fat metabolism. Heterogeneity among depots results, in part, from distinct intrinsic characteristics of adipose cells. Different depots are effectively separate miniorgans.

Reduced oxidized low-density lipoprotein after weight reduction in obese premenopausal women

BACKGROUND

Several studies support the hypothesis that oxidation of low-density lipoprotein (LDL) promotes atherogenesis. Obesity is one of the risk factors of atherosclerosis, but it is not known whether obesity is related to LDL oxidation.

OBJECTIVE AND DESIGN

We investigated the effect of weight reduction and subsequent weight maintenance program on LDL oxidation in 77 obese premenopausal women (BMI 29-46 kg/m(2)). Another group of seven obese women served as a control group. Oxidized LDL was measured as baseline concentration of conjugated dienes in LDL lipids (ox-LDL). The weight reduction was performed in 12 weeks, using a very-low-energy diet.

RESULTS

The mean weight loss was 13 kg (92 vs 79 kg). During weight reduction, the concentration of LDL cholesterol decreased by 11%, the concentration of ox-LDL decreased by 40%, and the ratio of ox-LDL to LDL by 33%. The concentration of LDL antioxidant capacity (LDL-TRAP) decreased by 8%, but the decrease was caused by the decrease in LDL. The concentration of LDL, ox-LDL or LDL-TRAP did not change in the control group. The weight reduction correlated with the decrease of ox-LDL. During the subsequent 9 month weight maintenance programme, the concentrations of serum LDL (10%), ox-LDL (11%), LDL-TRAP (29%), and the ratio of LDL-TRAP to LDL (21%) decreased.

CONCLUSION

This study strengthens the evidence that the risk of atherogenesis is influenced favourably by weight reduction in obese women. This risk reduction is associated with a reduced oxidation of LDL.

Body fat, fat distribution and serum lipids, lipoproteins and apolipoproteins in African-American and Caucasian-American prepubertal children

OBJECTIVE

The purpose of the present study was to determine the impact of body fat mass and fat distribution on serum lipids, lipoproteins and apolipoproteins in African-American and Caucasian-American prepubertal children.

SUBJECTS

Study participants included 62 African-American children (age 8.3+/-1.4 y; body mass 37.3+/-13.6 kg; height 133+/-11 cm) and 39 Caucasian children (age 8.6+/-1.2 y; body mass 34.1+/-11.0 kg; height 131+/-9 cm).

METHODS

Venous blood samples were obtained after a 12 h overnight fast and serum was analyzed for total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-C), triacylglycerol (TAG), apolipoprotein A-I (ApoA-I), apolipoprotein B (ApoB) and lipoprotein (a) (Lp(a)) concentrations. Body composition and body fat distribution were measured by dual-energy X-ray absorptiometry and computed tomography, respectively.

RESULTS

African-American children had lower TAG (46+/-20 vs 61+/-32 mg/dl, P=0.015) and higher Lp(a) (34+/-25 vs 17+/-28 mg/dl, P=0.001) and HDL-C (44+/-11 vs 39+/-8 mg/dl, P=0.041). There were no ethnic differences in TC, ApoA-I and ApoB (P=0.535, P=0.218, P=0.418, respectively). The ethnic difference in TAG and Lp(a) was not explained by total fat or abdominal fat. The ethnic difference in HDL-C was explained by visceral fat and TAG.

CONCLUSION

In prepubertal children, neither body fat nor fat distribution explain the ethnic difference in TAG or Lp(a), but visceral fat and TAG may contribute to differences in HDL-C.

High plasma nonesterified fatty acids are predictive of cancer mortality but not of coronary heart disease mortality: results from the Paris Prospective Study

To assess the association of fasting plasma nonesterified fatty acid (NEFA) concentration with the risk of death from coronary heart disease and cancer, the authors computed 15-year mortality rates for the 4,589 working men aged 43-53 years who were included in the Paris Prospective Study between 1967 and 1972. A total of 251 and 126 men died from cancer and coronary heart disease, respectively. For coronary heart disease death, the age- and tobacco-adjusted relative risk for men in the highest 20% of the fasting plasma NEFA concentrations compared with those in the lowest 80% was 1.54 (95% confidence interval (CI): 1.01, 2.34). It became nonsignificant after further adjustment for blood pressure, iliac/thigh ratio, and plasma insulin and cholesterol concentrations. In contrast, a high fasting plasma NEFA concentration exhibited a strong independent relation with cancer mortality (relative risk = 1.66, 95% CI: 1.25, 2.21, after adjustment for age, cigarette consumption, heart rate, and body mass index). Despite pathophysiologic mechanisms linking NEFA metabolism with visceral fat and plasma glucose, insulin, and triglyceride concentrations, the plasma NEFA concentration does not appear to be a good marker for coronary heart disease risk. In contrast, an unexpected association with cancer mortality was found that may point to the need for further investigation.

Hypertension and type 2 diabetes comorbidity in adults in the United States: risk of overall and regional adiposity

OBJECTIVE

To evaluate the impact of generalized, abdominal, and truncal fat deposits on the risk of hypertension and/or diabetes and to determine whether ethnic differences in these fat patterns are independently associated with increased risk for the hypertension-diabetes comorbidity (HDC).

RESEARCH METHODS AND PROCEDURES

Data (n = 7075) from the Third U.S. National Health and Nutrition Examination Survey were used for this investigation. To assess risks of hypertension and/or diabetes that were due to different fat patterns, odds ratios of men and women with various cut-points of adiposities were compared with normal subjects in logistic regression models, adjusting for age, smoking, and alcohol intake. To evaluate the contribution of ethnic differences in obesity to the risks of HDC, we compared blacks and Hispanics with whites.

RESULTS

Generalized and abdominal obesities were independently associated with increased risk of hypertension, diabetes and HDC in white, black, and Hispanic men and women. The risk of HDC due to generalized, truncal, and abdominal obesities tended to be higher in whites than blacks and Hispanics. In men, the contribution of black and Hispanic ethnicities to the increased risk of HDC due to the various obesity phenotypes was approximately 73% and approximately 61%, respectively. The corresponding values for black and Hispanic women were approximately 115% and approximately 125%, respectively.

CONCLUSIONS

In addition to advocating behavioral lifestyles to curb the epidemic of obesity among at-risk populations in the United States, there is also the need for primary health care practitioners to craft their advice to the degree and type of obesity in these at-risk groups.

Determinants of body composition in postmenopausal women

BACKGROUND

Little is known about the effects of different levels of long-term physical activity on total body and regional fat and whether hormone replacement therapy interacts with physical activity level to affect body composition in postmenopausal women.

METHODS

We determined the associations between different levels of habitual physical activity, hormone replacement therapy (HRT), and total and regional body composition in postmenopausal women. Twenty sedentary, 20 active nonathletic, and 23 endurance-trained women (approximately half on HRT) had total and regional body composition assessed by dual-energy x-ray absorptiometry. The athletes and active nonathletic women had been active for the same number of years and the same number of hours per week.

RESULTS

The athletes and sedentary women weighed the same, but the active nonathletic groups on and not on HRT weighed 3-12 kg more (p < .05). Athletes had less trunk, arm, leg, and total body fat than sedentary and active nonathletic women (p < .05). Women on HRT tended to have lower total body (p = .07), but not regional, fat values. Linear regression analyses indicated that VO2max in ml/kg/min was the major independent determinant of total and regional body fat accounting for 52% to 70% of their variances. Athletes had greater caloric and carbohydrate intake than their less active peers, but all groups had similar protein, fat, saturated fat, monounsaturated fat, and polyunsaturated fat intakes.

CONCLUSIONS

Intense training, but not low- to moderate-intensity physical activity, is associated with markedly lower levels of total and regional body fat in postmenopausal women. HRT has less of an effect on body composition than intense exercise training in postmenopausal women.

Self-help weight loss versus a structured commercial program after 26 weeks: a randomized controlled study

PURPOSE

There have been few randomized controlled trials of commercial weight-loss programs. This ongoing study compares the effects of a self-help program and a commercial program on weight loss and other measures of obesity in overweight and obese men and women.

SUBJECTS AND METHODS

We report the results of the first 26 weeks of a multicenter, randomized, 2-year study of 423 subjects who had a body mass index of 27 to 40 kg/m(2). Subjects were randomly assigned to either a self-help program, consisting of two 20-minute sessions with a nutritionist and provision of printed materials and other self-help resources, or to attendance at meetings of a commercial program (Weight Watchers). Outcome measures were changes in body weight, body mass index, waist circumference, and body fat. Changes in serum homocysteine levels were measured in a subsample of participants during the first 12 weeks.

RESULTS

After 26 weeks, subjects in the commercial program, as compared with those in the self-help program, had greater decreases in body weight [mean (+/- SD) -4.8+/-5.6 vs -1.4+/-4.7 kg] and body mass index (-1.7+/-1.9 vs -0.5+/-1.6 kg/m(2), both P<0.001) in intention-to-treat analyses. Among subjects measured at week 26, mean waist circumference (-4.3+/-10.5 vs -0.7+/-12.7 cm) and fat mass (-3.8 +/-7.0 vs -1.5+/-7.6 kg, both P<0.05) also decreased more among subjects in the commercial program. Mean serum homocysteine levels improved in the commercial program compared with self-help (-0.5+/-1.3 vs 0.9+/-1.8 microM, P<0.05).

CONCLUSIONS

A structured commercial weight-loss program is more likely to be effective for managing moderately overweight patients than brief counseling and self-help.

Stroke risk from multiple risk factors combined with hypertension: a primary care based case-control study in a defined population of northwest England

PURPOSE

To examine how hypertension interacts with other known risk factors in affecting the risk of stroke in a primary care based setting.

METHODS

Cases were patients with first-ever stroke identified from the community-based stroke register in 1994-95 in northwest England. Two controls per case were randomly selected from the same primary care site and matched by age and sex. Information on predefined risk factors was extracted from medical records.

RESULTS

267 cases and 534 controls were included. Adjusted odds ratio (OR) for stroke from hypertension was 2.6 (95% confidence interval: 1.7-3.9). In hypertensives who were current smokers, risk of stroke was increased 6 fold as compared to non-smokers without hypertension. Hypertensives who had a preexisting history of myocardial infarction or obesity or diabetes had 3 fold higher risks of stroke. Subjects with hypertension and with a history of transient ischemic attack or atrial fibrillation had > or = 8 fold excess risk of stroke. Among them, the risk was greater in those with poorly controlled or untreated hypertension and in those with well or moderately controlled as compared to subjects without both risk factors. There appeared to be a steady increase in risk of stroke according to the number of risk factors present, particularly in hypertensive subjects.

CONCLUSIONS

Stroke risks in hypertensives associated with combinations of other risk factors appeared to follow an additive model. Subjects with multiple risk factors should be targeted in order to reduce the overall risk for stroke.

Inheritance of the waist-to-hip ratio in the National Heart, Lung, and Blood Institute Family Heart Study

OBJECTIVE

Considering that waist-to-hip ratio (WHR) is a simple anthropometric measure of obesity and is a better predictor of coronary heart disease than body mass index (BMI), the genetic underpinnings of WHR are of interest. The inheritance pattern of WHR, before and after adjustment for BMI (WHR-BMI), was investigated in 2713 individuals from 1038 nuclear families in the National Heart, Lung, and Blood Institute Family Heart Study (NHLBI-FHS).

RESEARCH METHODS AND PROCEDURES

Waist and hip measurements were taken twice, and the means of the measurements were used to calculate the WHR. Adjustments for age were carried out separately by sex, using stepwise multiple regression procedures for WHR and WHR-BMI phenotypes. Segregation analysis was applied using the unified model as implemented in the computer program POINTER.

RESULTS

For age-adjusted WHR, the segregation results suggested an additive major gene that accounts for 35% of the phenotypic variance, and approximately 30% of the sample are homozygous for the "high" genotype. The results for age- and BMI-adjusted WHR were also compatible with a major gene; however, the multifactorial model provided the most parsimonious fit to the data.

DISCUSSION

Although the genetic mechanisms for several obesity traits have been studied, tests of Mendelian segregation on this simple anthropometric measure (WHR) have not been reported previously. This study provides evidence for the presence of a major gene for age-adjusted WHR, suggesting that it is an appropriate trait for further genetic analysis, especially because it has strong predictive value and probably relates biologically to cardiovascular risk.

Diet and pharmacologic therapy of obesity to modify atherosclerosis

More than half of the men and women in the United States are overweight or obese. Obesity is associated with an increased risk for various diseases, most notably, hypertension, diabetes mellitus, dyslipidemia, and coronary heart disease (CHD). The location of excessive body fat, particularly in the visceral area, has the strongest association with these factors that comprise the insulin resistance syndrome. A reduction in as little as 10% of baseline weight has been shown to improve the control of blood pressure and glucose, as well as to reduce triglycerides and increase high-density lipoprotein (HDL) cholesterol. Therefore, obesity should be considered a predisposing CHD risk factor, and treatment with diet, exercise, and newer pharmacologic agents can help patients achieve and maintain desired weight-loss goals.

Body fat distribution and cardiovascular risk in normal weight women. Associations with insulin resistance, lipids and plasma leptin

OBJECTIVE

To systematically examine the correlations between insulin resistance, plasma leptin concentration, obesity and the distribution of fat assessed by anthropometry and magnetic resonance imaging in Asian women.

DESIGN

A cross sectional study of non-diabetic, normal weight women.

SUBJECTS

Twenty-one healthy women aged 38.8 y (s.d. 11.7) and BMI 22.6 kg/m2 (s.d. 2.3).

MEASUREMENTS

Intraperitoneal, retroperitoneal and subcutaneous abdominal fat volume was assessed by magnetic resonance imaging. Anthropometric data were collected. Total fat mass was assessed by bioelectric impedance analysis. Fasting serum lipids, insulin and plasma leptin were assayed.

RESULTS

Generalized obesity correlated with subcutaneous abdominal fat mass (r=0.83, P<0.001), but not with intra-abdominal fat mass. Both intraperitoneal fat mass and retroperitoneal fat mass increased with age (r=0.58, P=0.005 and r=0. 612, P=0.003, respectively). Abdominal subcutaneous fat mass was the most important determinant of insulin resistance and plasma leptin. Of the serum lipids, only fasting triglyceride correlated significantly with the waist-to-hip ratio.

CONCLUSIONS

It is possible that the large size of the subcutaneous depot compared to the intra-abdominal depot overwhelms any metabolic differences between adipose tissue from these two sites, resulting in the stronger correlation between insulin resistance and subcutaneous abdominal fat mass rather than intra-abdominal fat mass. On the other hand, the distribution of fat between subcutaneous fat depots may be important in the metabolic syndrome given the correlation of fasting triglyceride with waist to hip ratio but not with abdominal fat. However, the study population was small, younger and leaner compared to previous studies and we may not be able to generalize these results to all segments of the population. We confirm that subcutaneous fat mass is the major determinant of plasma leptin.

Dietary diacylglycerol suppresses accumulation of body fat compared to triacylglycerol in men in a double-blind controlled trial

We examined the effects of the long-term ingestion of dietary diacylglycerols (DG) in a double-blind controlled study of human lipid metabolism. Healthy men (n = 38; aged from 27 to 49 y, body mass index (BMI) ranging from 21.8 to 27.4 kg/m(2)) completed the study. To accustom the subjects to the test diets prior to the experiment, they were supplied with test diets of triacylglycerol (TG) oil for 4 wk (control period). The test oils (10 g/d) were included in bread, mayonnaise or shortbread and served for the breakfast. The target for total lipid intake was 50 g/d (15 g for breakfast, 15 g for lunch and 20 g for dinner) throughout the study. The subjects were then divided into two groups so that mean BMI and the hepatic fat content, determined by computed tomography, for each group were not different. One group (DG group) consumed test meals containing DG-rich oil (10 g/d) while the other group (TG group) consumed the same meal as during the control period. Ten grams of the DG-rich oil contained 5.5 g 1,3-DG, 2.5 g 1,2-DG and 2 g TG. The actual lipid intake during the study was 43 g/d. Body weight, BMI and waist circumference decreased in both groups at the end of the test period of 16 wk. However, the magnitudes of decreases in these variables were significantly greater in the DG group than in the TG group. Decreases of total fat, visceral fat area and subcutaneous fat area of the abdominal traverse images of computed tomography in the DG group were also significantly greater than those in the TG group. Hepatic fat content decreased significantly in the DG group while no change was observed in the TG group. Serum lipid concentrations (TG, total cholesterol, free fatty acid) and related metabolites (glucose, insulin, total ketone body) did not change significantly in either group. Thus, in contrast to TG, DG apparently suppressed accumulation of fat and possibly reduces the risk of diseases associated with visceral fat obesity.

[Factors associated with the accumulation of abdominal fat estimated with anthropometric indexes]

BACKGROUND

To evaluate lifestyle and dietary intake factors influencing the accumulation of abdominal fat in a Mediterranean population.

SUBJECTS AND METHOD

A cross-sectional study was carried-out in Spain (Asturias, Granada, Murcia, Navarra and Guipuzkoa) among 23,228 women and 14,332 men aged 29-69 years, participants of a large European prospective cohort (EPIC). Information on usual food intake and other non-dietary factors were collected by interviews. Height, weight, waist circumference and hip circumference were taken by previously trained interviewers.

RESULTS

In a multiple-linear regression analysis sports activities and educational level were negatively associated with abdominal obesity, while body mass index, age, tobacco and alcohol consumption, saturated fat intake and increased prevalence of hypertension, diabetes and myocardial infarction were positively associated. All dietary and non-dietary variables accounted for 22 and 27% of variance in the waist/hip ratio and 74 and 66% of variance in the waist circumference, in women and men respectively.

CONCLUSIONS

Body mass index and age are the most important factors influencing the accumulation of abdominal fat. Dietary factors and other lifestyle factors seem to play a minor role in increasing abdominal obesity.

Treatment with metformin of non-diabetic men with hypertension, hypertriglyceridaemia and central fat distribution: the BIGPRO 1.2 trial

BACKGROUND

In the BIGPRO 1 trial, one year of treatment with metformin in non-diabetic obese subjects with a central fat distribution had no significant effect on fasting plasma triglyceride concentration or on blood pressure despite a decrease in weight, fasting plasma insulin and glucose concentrations. To re-evaluate the effect of metformin on fasting triglyceride concentration and on blood pressure, the BIGPRO 1.2 trial included non-diabetic men (n=168) with a fasting plasma triglyceride concentration > or =1.7 and < or =6.5 mmol/l, high blood pressure (systolic > or =140 and < or =180 and/or diastolic > or =90 and < or =105 mmHg, or treatment for hypertension) and a waist-to-hip ratio > or =0.95.

METHODS

A randomised double-blind trial comparing metformin treatment (850 mg bid) with placebo.

RESULTS

Metformin had no significant effect either on blood pressure or plasma triglyceride concentration. In comparison with the placebo group, fasting plasma insulin (p<0.04), total cholesterol (p<0.05) and Apo B (p<0.008) concentrations decreased more in the metformin group in the BIGPRO 1. 2 trial, confirming most of the previous results of the BIGPRO 1 trial. Tissue plasminogen activator antigen concentration decreased significantly (p<0.01) only in the metformin group, but this was not significantly different from the placebo group (p<0.12); further, there were no significant differences in the change in plasminogen activator inhibitor 1.

CONCLUSIONS

The consistency of the two BIGPRO trials supports the conclusion that metformin affects several cardiovascular risk factors favourably in non-diabetic subjects with a central fat distribution.

Time since immigration and excess body weight

OBJECTIVES

To examine the relationship between time since immigration and excess body weight.

METHODS

Secondary data analysis of a cross-sectional survey of 19,600 Canadians.

RESULTS

The prevalence of excess weight (BMI > 25) increases with time since immigration for both men and women. After controlling for birthplace, socio-demographic, lifestyle and health correlates, only female immigrants (less than five years) are significantly less likely to have BMI scores greater than 25 kg/m2 compared to those born in Canada. Stratified analyses, however, revealed similar findings for Asian men who had immigrated less than five years prior to the survey.

DISCUSSION

Our results suggest that length of time since immigration is an important risk factor for excess weight. Further research with longitudinal data, more reliable measures of ethnicity and anthropometric measures of weight are required to confirm these initial findings.

Body-composition changes with diet and exercise in obese women: a comparison of estimates from clinical methods and a 4-component model

BACKGROUND

Most methods available to clinicians for estimating body-composition changes have been validated against estimates from densitometry, based on a 2-component (fat mass and fat-free mass) model.

OBJECTIVE

Estimates of changes in percentage body fat (%BF) from dual-energy X-ray absorptiometry (DXA), skinfold thicknesses (SFTs), bioelectrical impedance analysis (BIA), and body mass index (BMI; in kg/m2) were compared with estimates from a 4-component (fat, water, mineral, and protein) model (%BFd,w,m), a more accurate method.

DESIGN

Determinations of body density from hydrostatic weighing, body water from deuterium dilution, bone mineral and %BF from whole-body DXA, resistance from BIA, and anthropometric measures were made in 27 obese women (BMI: 31.1 +/- 4.9) assigned to 1 of 3 groups: control (C; n = 9), diet only (DO; n = 9), or diet plus aerobic exercise (DE; n = 9).

RESULTS

After the 16-wk intervention, changes in body mass (BM) averaged 0.5 +/- 2.0, -7.2 +/- 7.4, and -4.0 +/- 3.3 kg and changes in %BFd,w,m averaged 2.1 +/- 1.0%, -1.2 +/- 1.4%, and -2.4 +/- 1.6% in the C, DO, and DE groups, respectively. Compared with changes in %BFd,w,m, the errors (SD of bias) for estimates of changes in %BF by DXA, BIA, SFTs, and BMI were similar (range: +/-2.0-2.4% of BM). BIA, SFTs, and BMI provided unbiased estimates of decreases in %BFd,w,m, but DXA overestimated decreases in %BF in the DO and DE groups.

CONCLUSIONS

DXA, BIA, SFTs, and BMI are comparably accurate for evaluating body-composition changes induced by diet and exercise interventions; however, small changes in %BF may not be accurately detected by these clinical methods.

Racial differences in amounts of visceral adipose tissue in young adults: the CARDIA (Coronary Artery Risk Development in Young Adults) study

BACKGROUND

In several white populations, visceral adipose tissue (VAT) is a risk factor for development of type 2 diabetes and dyslipidemia. VAT can be accurately assessed by computed topography or magnetic resonance imaging, but is also estimated from anthropometric variables, such as waist-to-hip ratio, waist circumference, or sagittal diameter. To date, anthropometric variables have been used largely in whites and inadequate data are available to evaluate the validity of these variables in other groups.

OBJECTIVES

The objectives of this study were to 1) determine whether amount of VAT in relation to total body fatness differs in different race and sex groups and 2) determine which anthropometric variables predict amount of VAT in different race and sex groups.

DESIGN

We determined the amount and location of body fat, including assessment of VAT by computed tomography, in young adult white and black men and women participating in the 10-y follow-up of the CARDIA (Coronary Artery Risk Development in Young Adults) Study.

RESULTS

Black men had less visceral fat (73.1+/-35.9 cm2) than white men (99.3+/-40 cm2), even when VAT was corrected for total body fatness. Black women were more obese than white women and thus had more visceral fat (75.1+/-37.5 compared with 58.6+/-35.9 cm2, respectively). This difference disappeared when corrected for total body fatness.

CONCLUSIONS

Both waist circumference and sagittal diameter were good predictors of VAT in all groups. However, the nature of this relation differed such that race- and sex-specific equations will likely be required to estimate VAT from waist circumference or sagittal diameter.

The effects of potassium, magnesium, calcium, and fiber on risk of stroke

Stroke mortality represents the third leading cause of death worldwide, after coronary artery disease and cancer. High blood pressure is a major risk factor for stroke. A recent study has identified potassium, magnesium, and fiber as significant modulators of stroke risk in men. The protective effects were particularly pronounced in hypertensive subjects. The observed protection may be due to direct and indirect effects of these nutrients on blood pressure and regulatory functions, such as endothelial function. A high intake of these nutrients, singularly or in combination, is associated with a more healthful overall lifestyle. The best strategy to achieve a high intake of these nutrients is a diet rich in fruits and vegetables.

Factors associated with overweight and obesity among Kuwaiti college women

A random sample of 585 Kuwaiti college women was studied in 1997 for factors associated with overweight and obesity. Weight and height were measured. The index of adiposity used was the body mass index (BMI), which is the weight in kilograms divided by the height squared (W/H2). The women were classified as overweight or obese (BMI > 25 or > 30 Kg/m2). The associated factors obtained through questionnaires included age, marital status, area of residence, number of siblings, (brothers, sisters, total), suffering from a chronic disease, obesity among parents, parents' education and occupation, number of major meals eaten, eating between meals, family income, number of servants, number of people living at home, exercising, last dental and physical checkup, dieting, year of study, highest desired degree, countries prefer visiting, and socioeconomic status (SES). The results of the study revealed that 27.2 and 7.2% of the students were overweight (BMI > 25 Kg/m2) and obese (BMI > 30 Kg/m2), respectively. Factors that were found to be significantly associated with overweight and obesity among the women included number of brothers, having a chronic disease, obesity among parents, dieting and countries prefer visiting. Logistic regression analysis of significant associated factors revealed that the same factors contributed to the development of overweight and obesity except number of brothers and having a chronic disease.

Genetic and behavioral determinants of waist-hip ratio and waist circumference in women twins

OBJECTIVES

This study examines genetic and behavioral determinants of waist-hip ratio (WHR) and waist circumference among women twins.

RESEARCH METHODS AND PROCEDURES

Six hundred eighty participants from the second examination of the Kaiser-Permanente Women Twins Study (1989 to 1990) were included. Women ranged in age from 31 to 90 years, and included 59% monozygotic and 41% dizygotic twins. Heritabilities of WHR and waist circumference were estimated (range=0 to 1) using three different statistical methods. Linear regression models that adjusted for the lack of independence within twin pairs were used to assess associations between behavioral variables, WHR, and waist circumference.

RESULTS

Age and body mass index-adjusted heritability estimates ranged from 0.36 to 0.61 for WHR and 0.72 to 0.82 for waist circumference. When considered individually, after adjusting for age and body mass index, all behavioral characteristics, except calorie-adjusted fat intake, were significantly (p<0. 10) associated with waist circumference and WHR. Greater central adiposity was associated with lower education, higher alcohol consumption, lower physical activity, current cigarette smoking, higher parity, and postmenopausal status without hormone replacement therapy. In multivariate models, these associations persisted, except neither educational attainment nor alcohol intake was significantly associated with waist circumference. In longitudinal analyses, both measures were positively associated with current or recent-past smoking; infrequent or inconsistent physical activity; and long-term, daily consumption of alcohol.

DISCUSSION

These cross-sectional and longitudinal associations are consistent with genetic and behavioral predictors of waist circumference and WHR. Whereas the evidence for genetic influences is stronger for waist circumference, both body fat measures may be similarly influenced by the behavioral factors considered.

Management of older persons after myocardial infarction

OBJECTIVE

To review the management of the older person after myocardial infarction (MI).

DATA SOURCES

A computer-assisted search of the English language literature (MEDLINE database) followed by a manual search of the bibliographies of pertinent articles.

STUDY SELECTION

Studies on the management of persons after MI were screened for review. Studies in persons older than 60 years and recent studies were emphasized.

DATA EXTRACTION

Pertinent data were extracted from the reviewed articles. Emphasis was on studies involving older persons. Relevant articles were reviewed in depth.

DATA SYNTHESIS

Available data about therapy of persons after MI, including control of risk factors, use of aspirin and beta-blockers, and indications for use of angiotensin-converting enzyme inhibitors, long-term anticoagulant therapy, nitrates, calcium channel blockers, hormone replacement therapy, antiarrhythmic drugs, the automatic implantable cardioverter-defibrillator, and revascularization, with emphasis on studies involving older persons, were summarized.

CONCLUSIONS

Risk factors for coronary artery disease should be controlled after MI in older persons. A serum low-density lipoprotein (LDL) cholesterol >125 mg/dL after MI should be treated with lipid-lowering drug therapy to decrease the serum LDL cholesterol to <100 mg/dL. Aspirin in a dose of 160 mg to 325 mg daily should be given indefinitely. Indications for long-term anticoagulant therapy with warfarin after MI to maintain an international normalized ratio between 2.0 and 3.0 include secondary prevention of MI in persons unable to tolerate daily aspirin, persistent atrial fibrillation, and left ventricular thrombus. Beta-blockers should be given indefinitely. Angiotensin-converting enzyme inhibitors should be given to persons who have congestive heart failure, an anterior MI, or a left ventricular ejection fraction < or = 40%. Calcium channel blockers should not be used unless there is persistent angina pectoris despite beta-blockers and nitrates. Antiarrhythmic drugs other than beta-blockers should not be used. An automatic implantable cardioverter-defibrillator should be used in persons who have a history of ventricular fibrillation or serious sustained ventricular tachycardia or who are at very high risk for developing sudden cardiac death. Until data from the Heart Estrogen/ Progestin Replacement Study are available, use of an estrogen/progestin regimen is recommended in the treatment of postmenopausal women after MI unless they are at increased risk for developing breast cancer. The two indications for revascularization in older persons after MI are prolongation of life and relief of unacceptable symptoms despite optimal medical management.

Hyperinsulinemia and the risk of stroke in healthy middle-aged men: the 22-year follow-up results of the Helsinki Policemen Study

BACKGROUND AND PURPOSE

Several studies have shown that hyperinsulinemia is associated with the risk of coronary heart disease, but information on the association of hyperinsulinemia with the risk of stroke is limited. We investigated the association of hyperinsulinemia with the risk of stroke during a 22-year follow-up of the Helsinki Policemen Study population.

METHODS

The study was based on a cohort of 970 men aged 34 to 64 years who were free of cerebrovascular disease, other cardiovascular disease, or diabetes. Risk factor measurements at baseline examination included an oral glucose tolerance test with blood glucose and plasma insulin measurements at 0, 1, and 2 hours. Area under the insulin response curve during oral glucose tolerance test was used as a composite variable reflecting plasma insulin levels.

RESULTS

During the 22-year follow-up, 70 men had a fatal or nonfatal stroke. Hyperinsulinemia (highest area under the insulin response curve quintile compared with the combined 4 lower quintiles) was associated with the risk of stroke (age-adjusted hazard ratio, 2.12; 95% CI, 1.28 to 3.49), but not independently of other risk factors (multiple-adjusted hazard ratio, 1.54; 95% CI, 0.90 to 2.62), which was mainly due to the impact of obesity, particularly upper body obesity, with subscapular skinfold thickness used as an index. Of other risk factors, upper body obesity, blood pressure, and smoking were independent predictors of the risk of stroke.

CONCLUSIONS

Hyperinsulinemia was associated with the risk of stroke in Helsinki policemen during the 22-year follow-up, but not independently of other risk factors, particularly upper body obesity.

Validity of self-reported fat distribution in young adults: the CARDIA Study. Coronary Artery Risk Development in Young Adults

To determine the validity of self-reported information on body fat distribution, relationships between reported location of weight gain and measured waist-to-hip ratio (WHR), high density lipoprotein cholesterol (HDL-C), and fasting insulin were analyzed in 5115 black and white men and women aged 18-30 years. In black men, WHR adjusted for age and body mass index (BMI) ranged from 0.833 among those reporting upper and central weight gain to 0.812 among those reporting lower body weight gain (trend across five reported fat distribution categories, P = 0.0004). Corresponding values were, for white men, 0.852 to 0.831; for black women, 0.777 to 0.721; and for white women, 0.772 to 0.701 (each P < 0.0001). Reported fat distribution was associated with HDL-C in women, but not in men, and with fasting insulin in all groups. While these associations were somewhat weaker than with measured WHR, self-reported fat distribution does provide valid information about body fat distribution in young adults, particularly women.

Changes in body mass index and prevalence of obesity among adult Kuwaiti women attending health clinics

This study was undertaken to compare changes in body mass index (BMI, kg/m 2) and in prevalence of adiposity (BMI>25 and >30 kg/m 2) between two cross-sections of previously studied samples of 1171 and 1705 adult (aged >/=18 years) Kuwaiti women drawn from primary health care (PHC) clinics and studied for nutritional assessment and for prevalence of obesity in 1980-1981 and 1993-1994, respectively. Mild and moderate obesity (BMI>25 and >30 kg/m 2) were assessed based on the WHO criteria. The results of the study showed that BMI and prevalence of obesity (BMI>25 and >30 kg/m 2) increased by 6.2% (1.7 kg/m2), 22.7% and 8.4%, respectively. After controlling for sociodemographic differences between the two study periods, including period of study, age, region, education, marital status and occupation, mean BMI was 1.6 kg/m 2 higher in 1993-1994 than in 1980-1981 and prevalence of obesity (BMI>25 and >30 kg/m 2) also increased between the two periods (OR-22, 95% CI 1.6-3.0 and OR=1.4 95% CI 1.0-1.9, respectively). The rates of increase in BMI and in prevalence of obesity among Kuwaiti women were higher than in selected other countries.

Regulation of body adiposity and the problem of obesity

The hypothesis that body adiposity is homeostatically regulated is the focus of an intensive research effort, and support for this concept is rapidly growing. While generating optimism about the future of obesity treatment, these advances also bear on our current approach to the obese patient. The observation that body adiposity appears to be subject to regulation in obese as well as lean individuals suggests that common forms of obesity may result from a primary disorder of the weight-regulatory system. As a result, voluntary efforts to lower body adiposity activate compensatory responses that limit weight loss and facilitate weight regain. The use of weight-reduction strategies based on caloric restriction, therefore, effectively pits the will of the obese individual against his or her own intrinsic weight-regulatory system. Until more effective approaches to weight reduction are available, we suggest that clinical intervention should focus on patient education and strategies to limit weight gain or modestly lower weight. Since the combination of a low-fat diet with an exercise program appears to reduce the level at which body weight is regulated without active caloric restriction, this approach may be appropriate for many obese individuals.

Simple anthropometric indices associated with ischemic heart disease

In a case-control study of 217 hospitalized incident cases of ischemic heart disease and 261 controls we compared various anthropometric indices for the strength of their associations to the outcome event. The ratio of supine sagittal abdominal diameter to midthigh girth ("abdominal diameter index"; ADI) was the simple index that best discriminated cases from controls for both men (standardized difference, 0.65; p < 0.0001) and women (standardized difference, 0.95; p < 0.0001). The waist-to-thigh ratio of girths (WTR) (standardized difference, 0.57 and 0.90; p < 0.0001) was nearly as strong as the ADI and stronger than the traditional waist-to-hip ratio (standardized difference, 0.34 and 0.68; p < 0.005). After adjustments for age and race, the men's odds ratio for ischemic heart disease (tertile 3 vs. tertile 1) was 5.5 (95% CI, 2.9-10) using ADI and 5.1 (2.6-10) using the WTR. The women's odds ratio was 6.3 (1.9-20) using ADI and 8.7 (2.3-33) using the WTR. Further adjustments for body mass index and cardiovascular risk factors did not substantially change these risk estimates. Similar odds ratios were estimated by analyses restricted to 169 neighborhood-matched case-control pairs. In contrast, increased midthigh girth and subcutaneous fat mass (sum of three skinfolds) were associated with a protective effect against ischemic heart disease. Anthropometry using the ADI or WTR could offer a low-cost, noninvasive method for the clinical or epidemiologic evaluation of ischemic heart disease risk.

Life changes, locus of control and metabolic syndrome precursors in adolescents and young adults: a three-year follow-up

The relations between life changes, locus of control and changes in the parameters of the metabolic syndrome were examined. A three-year follow-up study of 671 randomly selected, healthy adolescents and young adults was used. Somatic parameters measured both at the baseline and the follow-up were serum insulin, serum HDL chol, serum triglyceride, SBP and BMI. Locus of control was measured with the Nowicki-Strickland locus of control scale and subjects were asked about life changes that they had faced during the follow-up period. Results showed that, in women, there were significant main effects for life changes in predicting (high) somatic risk level, whereas, in men, an opposite association was found. In addition, locus of control had a moderating effect on the life change-metabolic parameters relation, i.e. most of the life changes predicted a lower level of somatic risk in subjects with an external rather than internal locus of control. Results question the universal applicability of beneficial health effects of internal locus of control. It was suggested that accumulation of life changes might contribute, in interaction with locus of control, to the early development of the metabolic syndrome.

Risk factors for death from stroke in middle-aged Lithuanian men: results from a 20-year prospective study

BACKGROUND AND PURPOSE

Although in eastern Europe, mortality from stroke at present is the highest in the world, no previous prospective study of the risk factors for stroke has been reported from this part of the world. The aim of our study, therefore, was to evaluate the relations between blood pressure, serum total cholesterol, glucose intolerance, body mass index, and cigarette smoking and the risk of death from stroke in middle-aged men in Kaunas, Lithuania.

METHODS

We conducted a prospective study with an average follow-up of 17.5 years of 2295 men who had participated in risk factor surveys within the framework of the world Health Organization Kaunas-Rotterdam Intervention Study from 1972 to 1974. Risk factors included in the current analyses were smoking, blood pressure, serum total cholesterol, glucose intolerance, diabetes, and body mass index. Age-and risk factor adjusted relative risks (RR) for death of stroke were determined by use of the Cox proportional hazards model.

RESULTS

The strongest risk factors for death from stroke in middle-age men were systolic blood pressure (RR=1.02; P=.0001), diabetes (RR=4.17; P=.02), and smoking (RR=2.01; P=.004). Serum cholesterol, impaired glucose tolerance, and body mass index were not related to the risk of death from stroke. Twenty-five percent and 19% of stroke deaths were attributed to hypertension and smoking, respectively.

CONCLUSIONS

Prevention and effective control of hypertension, smoking, and diabetes are the key elements in primary prevention of stroke in eastern Europe, where stroke mortality remains high.

Concept of bridging the gap from youth to adulthood

Clinical atherosclerotic cardiovascular disease reaches substantial incidence beginning at age 45 years in men and age 55 years in women but has its onset in childhood. Lesions progress in relation to exposure to identified risk factors and, once initiated, tend to be self-perpetuating. Because predisposing factors are often initiated in childhood, interventions beginning early in life are optimal for prevention of adult disease. Even genetically predisposed people usually require an unfavorable lifestyle for the atherogenic trait to be expressed. No combination of risk factors entirely accounts for the increase in clinical atherosclerotic events with advancing age. This may be a reflection of longer exposure to risk factors or impaired ability to cope with them in advanced age. The declining risk factor risk ratios with advancing age may be a consequence of the selective early removal of those most susceptible from the population at risk. Risk of major cardiovascular events increases about 2.5-fold with each 10 years of age, even in people without major risk factors who are considered at low risk for atherosclerotic cardiovascular events. However, at any age vulnerability to cardiovascular events is strongly influenced by the burden of risk factors. Decreased risk ratios with advanced age are offset by a greater absolute risk. The female advantage over men erodes with age, with the menopause and with acquisition of an unfavorable lipid profile and glucose intolerance.

Waist circumference action levels in the identification of cardiovascular risk factors: prevalence study in a random sample

OBJECTIVE

To determine the frequency of cardiovascular risk factors in people categorised by previously defined "action levels" of waist circumference.

DESIGN

Prevalence study in a random population sample.

SETTING

Netherlands.

SUBJECTS

2183 men and 2698 women aged 20-59 years selected at random from the civil registry of Amsterdam and Maastricht.

MAIN OUTCOME MEASURES

Waist circumference, waist to hip ratio, body mass index (weight (kg)/height (m2)), total plasma cholesterol concentration, high density lipoprotein cholesterol concentration, blood pressure, age, and lifestyle.

RESULTS

A waist circumference exceeding 94 cm in men and 80 cm in women correctly identified subjects with body mass index of > or = 25 and waist to hip ratios > or = 0.95 in men and > or = 0.80 in women with a sensitivity and specificity of > or = 96%. Men and women with at least one cardiovascular risk factor (total cholesterol > or = 6.5 mmol/l, high density lipoprotein cholesterol < or = 0.9 mmol/l, systolic blood pressure > or = 160 mm Hg, diastolic blood pressure > or = 95 mm Hg) were identified with sensitivities of 57% and 67% and specificities of 72% and 62% respectively. Compared with those with waist measurements below action levels, age and lifestyle adjusted odds ratios for having at least one risk factor were 2.2 (95% confidence interval 1.8 to 2.8) in men with a waist measurement of 94-102 cm and 1.6 (1.3 to 2.1) in women with a waist measurement of 80-88 cm. In men and women with larger waist measurements these age and lifestyle adjusted odds ratios were 4.6 (3.5 to 6.0) and 2.6 (2.0 to 3.2) respectively.

CONCLUSIONS

Larger waist circumference identifies people at increased cardiovascular risks.

Evaluation of rate-pressure product in obese children

The purpose of this study was to evaluate the relationship between rate-pressure product (RPP) and degree of obesity in 511 obese 7 and 12 year old Chinese children. Obesity was assessed by anthropometry and skinfold thickness. The children were defined obese by relative weight (RW) > 120%. Bodyweight (W) and height (H) were used to derive body mass index (W/H2). Brachial systolic and diastolic pressures in these children were measured by cuff sphygmomanometry. RPP was calculated by the formula: heart rate x mean arterial pressure. More obese children (RW > or = 150%) had greater mean RPP (7 year old: 6389 vs 5976 beats/min x mmHg, P < 0.05; 12 year old: 7024 vs 6686 beats/min x mmHg) than those with RW < 150%. Children in the upper 25 percentiles of RPP had significantly larger BMI (7 and 12 year olds) and RW (12 year olds), thicker biceps, triceps and subscapular skinfolds (12 year olds) (P < 0.01-< 0.05). The results indicate that RPP is, to some extent, related to the degree of obesity in obese children. The differences in RPP may imply varying degrees of hemodynamic stress to the heart. Whether such differences may contribute to the long-term development of cardiovascular morbidity in more obese individuals is uncertain.