Antimetabolites and an optic neuropathy epidemic in Cuba.
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Antimetabolites↗
Biomedical subjects
A Ascherio
Publications and source records attributed to A Ascherio.
Health effects of trans fatty acids.
trans Fatty acids are formed during the process of partial hydrogenation in which liquid vegetable oils are converted to margarine and vegetable shortening. Concern has existed that this process may have adverse consequences because natural essential fatty acids are destroyed and the new artificial isomers are structurally similar to saturated fats, lack the essential metabolic activity of the parent compounds, and inhibit the enzymatic desaturation of linoleic and linolenic acid. In the past 5 y a series of metabolic studies has provided unequivocal evidence that trans fatty acids increase plasma concentrations of low-density-lipoprotein cholesterol and reduce concentrations of high-density-lipoprotein (HDL) cholesterol relative to the parent natural fat. In these same studies, trans fatty acids increased the plasma ratio of total to HDL cholesterol nearly twofold compared with saturated fats. On the basis of these metabolic effects and the known relation of blood lipid concentrations to risk of coronary artery disease, we estimate conservatively that 30,000 premature deaths/y in the United States are attributable to consumption of trans fatty acids. Epidemiologic studies, although not conclusive on their own, are consistent with adverse effects of this magnitude or even larger. Because there are no known nutritional benefits of trans fatty acids and clear adverse metabolic consequences exist, prudent public policy would dictate that their consumption be minimized and that information on the trans fatty acid content of foods be available to consumers.
Cholesterol↗
Vasectomy and prostate cancer: a case-control study in India.
BACKGROUND: The role of vasectomy in the development of prostate cancer remains controversial. In particular, there has been concern about detection bias and confounding in the previously published epidemiological studies examining this hypothesis. With the goal of minimizing detection bias, we have evaluated the relation between vasectomy and prostate cancer in a population without routine prostate cancer screening. METHODS: A case-control study consisting of 175 prostate cancer cases and 978 controls with cancer diagnoses other than prostate cancer was conducted at hospitals covered by the Bombay Cancer Registry in Bombay, India. History of vasectomy, demographic, and lifestyle factors were obtained by structured interview. Multiple logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI). RESULTS: Standardizing by age, 8.7% of cases and 8.3% of controls had had a vasectomy. The OR for prostate cancer comparing men who had had a vasectomy to those who did not was 1.48 (95% CI: 0.80-2.72) controlling for age at diagnosis, smoking status, alcohol drinking, and other demographic and lifestyle factors. Risk of prostate cancer associated with vasectomy appeared to be higher among men who underwent vasectomy at least two decades prior to cancer diagnosis or who were at least 40 years old at vasectomy. CONCLUSIONS: Although not statistically significant, the results of this hospital-based case-control study are consistent with the hypothesis of a positive association between vasectomy and prostate cancer. Because routine prostate cancer screening is not common in this population, detection bias was unlikely to account for this association.
Adult↗
Calcium intake and the incidence of forearm and hip fractures among men.
High calcium intakes are thought to be associated with strong bones and lower risk of fractures. However, findings from epidemiologic studies have not been consistent. In addition, the vast majority of such studies were conducted among women, leading to a relative lack of data concerning men. The objective of this study therefore was to investigate the relation between adult calcium intake and risk of fractures among men in the Health Professionals Follow-up Study (HPFS). During 331,234 person-years of follow-up over an 8-y period, 201 forearm and 56 hip fractures due to low or moderate trauma were reported among 43,063 men 40-75 y of age in 1986 when they first completed a questionnaire about diet and lifestyle factors. After controlling for age, smoking status, body mass index (BMI), physical activity, alcohol consumption and total energy intake, the relative risk (RR) of forearm fractures for men in the highest quintile of calcium intake (from foods plus supplements) compared with those in the lowest quintile was 0.98 [95% confidence interval (CI) = 0.59-1.61; P for trend = 0.78]; for hip fractures, the comparable RR was 1.19 (95% CI = 0.42-3.35; P for trend = 0.58). Relative risks for consuming >2.5 glasses (600 mL) of milk per day compared with one (240 mL) or fewer per week were 1.06 (95% CI = 0.69-1.62; P for trend = 0.82) for forearm fractures and 0.97 (95% CI = 0.39-2.42; P for trend = 0.56) for hip fractures. In conclusion, these results do not support a relation between calcium intake and the incidence of forearm or hip fractures in men.
Adult↗
Dietary fiber, glycemic load, and risk of NIDDM in men.
OBJECTIVE: Intake of carbohydrates that provide a large glycemic response has been hypothesized to increase the risk of NIDDM, whereas dietary fiber is suspected to reduce incidence. These hypotheses have not been evaluated prospectively. RESEARCH DESIGN AND METHODS: We examined the relationship between diet and risk of NIDDM in a cohort of 42,759 men without NIDDM or cardiovascular disease, who were 40-75 years of age in 1986. Diet was assessed at baseline by a validated semiquantitative food frequency questionnaire. During 6-years of follow-up, 523 incident cases of NIDDM were documented. RESULTS: The dietary glycemic index (an indicator of carbohydrate's ability to raise blood glucose levels) was positively associated with risk of NIDDM after adjustment for age, BMI, smoking, physical activity, family history of diabetes, alcohol consumption, cereal fiber, and total energy intake. Comparing the highest and lowest quintiles, the relative risk (RR) of NIDDM was 1.37 (95% CI, 1.02-1.83, P trend = 0.03). Cereal fiber was inversely associated with risk of NIDDM (RR = 0.70; 95% CI, 0.51-0.96, P trend = 0.007; for > 8.1 g/day vs. < 3.2 g/day). The combination of a high glycemic load and a low cereal fiber intake further increased the risk of NIDDM (RR = 2.17, 95% CI, 1.04-4.54) when compared with a low glycemic load and high cereal fiber intake. CONCLUSIONS: These findings support the hypothesis that diets with a high glycemic load and a low cereal fiber content increase risk of NIDDM in men. Further, they suggest that grains should be consumed in a minimally refined form to reduce the incidence of NIDDM.
Adult↗
Body size and fat distribution as predictors of stroke among US men.
Evidence for an association between general obesity and risk of stroke is weak. However, abdominal obesity may be more closely related to stroke risk. The association of body mass index and abdominal obesity (waist/hip ratio) with stroke incidence was examined in 28,643 US male health professionals, aged 40-75 years in 1986, who had no history of cardiovascular disease or stroke. In 5 years of follow-up, there were 118 cases of stroke, of which 80 were ischemic. Compared with men in the lowest quintile of body mass index, men in the highest quintile had an age-adjusted relative risk of stroke of 1.29 (95% confidence interval 0.73-2.27). In contrast, the age-adjusted relative risk for extreme quintiles of waist/hip ratio was 2.33 (95% confidence interval 1.25-4.37). This relative risk was not substantially altered in a multivariate model including body mass index, height, and other potential risk factors. There was a weaker relation with waist circumference alone, with men in the highest quintile (> 40.2 inches) having a relative risk of 1.52 (95% confidence interval 0.82-2.82) compared with men in the lowest quintile (< or = 34.5 inches) (1 inch = 2.54 cm). The results suggest that abdominal obesity, but not elevated body mass index, predicts risk of stroke in men.
Adult↗
Relation between intake of flavonoids and risk for coronary heart disease in male health professionals.
OBJECTIVE: Flavonols and flavones are subgroups of flavonoids and are found in tea, vegetables, fruits, and red wine. Because they have antioxidant properties, we investigated whether intake of these dietary compounds is associated with a lower risk for fatal and nonfatal coronary heart disease. DESIGN: Prospective cohort study. SETTING: United States. PATIENTS: 34,789 male health professionals, 40 to 75 years of age, who responded to a questionnaire in 1986. MEASUREMENTS: In 1986 and 1990, detailed, 131-item questionnaires were used to assess dietary intake of flavonols and flavones. RESULTS: Between 1986 and 1992, 496 patients received a new diagnosis of nonfatal myocardial infarction. The relative risk for nonfatal myocardial infarction was 1.08 (95% Cl, 0.81 to 1.43) for the highest (median, 40.0 mg/d) compared with the lowest (median, 7.1 mg/d) quintiles for intake of flavonols and flavones after adjustment for age, obesity, smoking, intake of vitamin E, intake of alcohol, diabetes, hypertension, hypercholesterolemia, and family history of coronary heart disease. Among the 4814 men who reported that they had previously had coronary heart disease, we found a modest but nonsignificant inverse association between intake of flavonols and flavones and subsequent coronary mortality rates (relative risk, 0.63 [Cl, 0.33 to 1.20] for the highest compared with the lowest quintile for intake of flavonoids). CONCLUSION: The data do not support a strong inverse association between intake of flavonoids and total coronary heart disease, but they do not exclude the possibility that flavonoids have a protective effect in men with established coronary heart disease.
Adult↗
Dietary fat and risk of coronary heart disease in men: cohort follow up study in the United States.
OBJECTIVE: To examine the association between fat intake and the incidence of coronary heart disease in men of middle age and older. DESIGN: Cohort questionnaire study of men followed up for six years from 1986. SETTING: The health professionals follow up study in the United States. SUBJECTS: 43 757 health professionals aged 40 to 75 years free of diagnosed cardiovascular disease or diabetes in 1986. MAIN OUTCOME MEASURE: Incidence of acute myocardial infarction or coronary death. RESULTS: During follow up 734 coronary events were documented, including 505 non-fatal myocardial infarctions and 229 deaths. After age and several coronary risk factors were controlled for significant positive associations were observed between intake of saturated fat and risk of coronary disease. For men in the top versus the lowest fifth of saturated fat intake (median = 14.8% v 5.7% of energy) the multivariate relative risk for myocardial infarction was 1.22 (95% confidence interval 0.96 to 1.56) and for fatal coronary heart disease was 2.21 (1.38 to 3.54). After adjustment for intake of fibre the risks were 0.96 (0.73 to 1.27) and 1.72 (1.01 to 2.90), respectively. Positive associations between intake of cholesterol and risk of coronary heart disease were similarly attenuated after adjustment for fibre intake. Intake of linolenic acid was inversely associated with risk of myocardial infarction; this association became significant only after adjustment for non-dietary risk factors and was strengthened after adjustment for total fat intake (relative risk 0.41 for a 1% increase in energy, P for trend < 0.01). CONCLUSIONS: These data do not support the strong association between intake of saturated fat and risk of coronary heart disease suggested by international comparisons. They are compatible, however, with the hypotheses that saturated fat and cholesterol intakes affect the risk of coronary heart disease as predicted by their effects on blood cholesterol concentration. They also support a specific preventive effect of linolenic acid intake.
Adult↗
Calcium, vitamin D, and dairy foods and the occurrence of colon cancer in men.
To examine the associations between intakes of calcium, Vitamin D, and dairy foods and the risk of colon cancer, the authors analyzed data from a prospective study of 47,935 US male professionals, 40-75 years of age and free of cancer in 1986. Within this cohort, 203 new cases of colon cancer were documented between 1986 and 1992. After adjusting for age and total energy intake, the authors found that the intake of calcium from foods and supplements was inversely associated with colon cancer risk (relative risk (RR) = 0.58, 95% confidence interval (CI) 0.39-087 between high and low intakes of calcium). However, after adjusting for confounding variables, they found that the trend was no longer statistically significant (p = 0.22), and the relative risk for the highest quintile group of intake was attenuated: 0.75 (95% CI 0.48-1.15). Similar results were observed for total vitamin D intake; the age- and energy-adjusted relative risk was 0.54% (95% CI 0/34-0/85) for the highest versus lowest quintile group, and this was attenuated in the multivariate model (RR = 0.66, 95% CI 0.42-1.05). The inverse association was weaker for dietary vitamin D (RR highest vs. lowest quintile = 0.88. 95% CI 0.54-1.42) and strongest for vitamin D arising from vitamin supplements (RR = 0.48, 95% CI 0.22-1.02). Thus, it is possible that other components of multivitamin use rather than vitamin D accounted for the reduction in risk. Consumption of milk and fermented dairy products was not significantly associated with the risk of colon cancer; individuals consuming two or more glasses of "whole" or skim milk per day had a relative risk of 1.09 (95% CI 0.69-1.72), compared with those who consumed "whole or skim milk less than once a month. These prospective data do not support the hypothesis that calcium intake is strongly protective against colon cancer risk, although a modest association cannot be excluded.
Adult↗
Premature coronary deaths in Asians.
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Adipose Tissue↗
Vegetable, fruit, and cereal fiber intake and risk of coronary heart disease among men.
OBJECTIVE: To examine prospectively the relationship between dietary fiber and risk of coronary heart disease. DESIGN: Cohort study. SETTING: In 1986, a total of 43,757 US male health professionals 40 to 75 years of age and free from diagnosed cardiovascular disease and diabetes completed a detailed 131-item dietary questionnaire used to measure usual intake of total dietary fiber and specific food sources of fiber. MAIN OUTCOME MEASURE: Fatal and nonfatal myocardial infarction (MI). RESULTS: During 6 years of follow-up, we documented 734 cases of MI (229 were fatal coronary heart disease). The age-adjusted relative risk (RR) for total MI was 0.59 (95% confidence interval [CI], 0.46 to 0.76) among men in the highest quintile of total dietary fiber intake (median, 28.9 g/d) compared with men in the lowest quartile (median, 12.4 g/d). The inverse association was strongest for fatal coronary disease (RR, 0.45; 95% CI, 0.28 to 0.72). After controlling for smoking, physical activity and other known nondietary cardiovascular risk factors, dietary saturated fat, vitamin E, total energy intake, and alcohol intake, the RRs were only modestly attenuated. A 10-g increase in total dietary fiber corresponded to an RR for total MI of 0.81 (95% CI, 0.70 to 0.93). Within the three main food contributors to total fiber intake (vegetable, fruit, and cereal), cereal fiber was most strongly associated with a reduced risk of total MI (RR, 0.71; 95% CI, 0.55 to 0.91 for each 10-g increase in cereal fiber per day). CONCLUSIONS: Our results suggest an inverse association between fiber intake and MI. These results support current national dietary guidelines to increase dietary fiber intake and suggest that fiber, independent of fat intake, is an important dietary component for the prevention of coronary disease.
Adult↗
Reproducibility and validity of a self-administered physical activity questionnaire for male health professionals.
We assessed the reproducibility and validity of a self-administered physical activity questionnaire used in a prospective study of 51,529 men. The questionnaire was administered by mail twice to 238 participants 2 years apart. During this interval, the participants completed a past-week recall and a 1-week activity diary at four times corresponding to different seasons throughout a year. Also, a step test was taken by a subset of the study participants. The intraclass correlation coefficients used to measure reproducibility were 0.39 for inactivity, 0.42 for nonvigorous activity, and 0.52 for vigorous activity. The correlations between diary-based and questionnaire-based activity scores, adjusted for variation in the diary measurements, were 0.41 for inactivity, 0.28 for nonvigorous activity, and 0.58 for vigorous activity. The distribution of activity scores was similar between the questionnaires and the average of past-week recalls, indicating the participants' ability to incorporate seasonal variation into their recall on a questionnaire. The correlation between vigorous activity and resting pulse was -0.45, whereas, for the pulse rate after stepping, the correlation was -0.41. These data indicate that this physical activity questionnaire is reproducible and provides a useful measure of average weekly activity, particularly vigorous activity, over a 1-year period.
Adult↗
A prospective study of social networks in relation to total mortality and cardiovascular disease in men in the USA.
STUDY OBJECTIVE: Previous studies have established a relationship between low levels of social networks and total mortality, but few have examined cause specific mortality or disease incidence. This study aimed to examine prospectively the relationships between social networks and total and cause specific mortality, as well as cardiovascular disease incidence. DESIGN: This was a four year follow up study in an ongoing cohort of men, for whom information on social networks was collected at baseline. The main outcome measures were total mortality, further categorised into deaths from cardiovascular disease (stroke and coronary heart disease), total cancer, accidents/suicides, and all other causes; as well as stroke and coronary heart disease incidence. PARTICIPANTS: Altogether 32,624 US male health professionals aged 42 to 77 years in 1988, who were free of coronary heart disease, stroke, and cancer at baseline. RESULTS: A total of 511 deaths occurred during 122,911 person years of follow up. Compared with men with the highest level of social networks, socially isolated men (not married, fewer than six friends or relatives, no membership in church or community groups) were at increased risk for cardiovascular disease mortality (age adjusted relative risk, 1.90; 95% CI 1.07, 3.37) and deaths from accidents and suicides (age adjusted relative risk 2.22; 95% CI 0.76, 6.47). No excess risks were found for other causes of death. Socially isolated men were also at increased risk of stroke incidence (relative risk, 2.21; 95% CI, 1.12, 4.35), but not incidence of non-fatal myocardial infarction. CONCLUSIONS: Social networks were associated with lower total mortality by reducing deaths from cardiovascular disease and accidents/suicides. Strong social networks were associated with reduced incidence of stroke, though not of coronary heart disease. However, social networks may assist in prolonging the survival of men with established coronary heart disease.
Accidents↗
Prospective study of nutritional factors, blood pressure, and hypertension among US women.
We examined prospectively the relation of nutritional factors with hypertension and blood pressure levels among 41,541 predominantly white US female nurses, aged 38 to 63 years, who completed a detailed semiquantitative food frequency questionnaire in 1984 and were without diagnosed hypertension, cancer, or cardiovascular disease. During 4 years of follow-up, from 1984 to 1988, 2,526 women reported a diagnosis of hypertension. Age, relative weight, and alcohol consumption were the strongest predictors for the development of hypertension. Dietary calcium, magnesium, potassium, and fiber were not significantly associated with risk of hypertension, after adjusting for age, body mass index, alcohol, and energy intake. Among women who did not report hypertension during the follow-up period, calcium, magnesium, potassium, and fiber were each significantly inversely associated with self-reported systolic and diastolic pressures, after adjusting for age, body mass index, alcohol consumption, and energy intake. When the four nutrients were added simultaneously to the regression model, only fiber and magnesium intakes retained significant inverse associations with systolic and diastolic pressures. In analyses of food groups, intakes of fruit and vegetables were inversely associated with systolic and diastolic pressures, and intakes of cereals and meat were directly associated with systolic pressure. These results support hypotheses that age, body weight, and alcohol consumption are strong determinants of risk of hypertension in middle-aged women. They are compatible with the possibilities that magnesium and fiber as well as a diet richer in fruits and vegetables may reduce blood pressure levels.
Adult↗
Poor oral health and coronary heart disease.
A few recent studies have shown associations between poor oral health and coronary heart disease (CHD). The objective of this study was to examine the incidence of CHD in relation to number of teeth present and periodontal disease, and to explore potential mediators of this association, in a prospective cohort study. This study is a part of the ongoing Health Professionals Follow-Up Study (HPFS). Participants included a US national sample of 44,119 male health professionals (58% of whom were dentists), from 40 to 75 years of age, who reported no diagnosed CHD, cancer, or diabetes at baseline. We recorded 757 incident cases of CHD, including fatal and non-fatal myocardial infarction and sudden death, in six years of follow-up. Among men who reported pre-existing periodontal disease, those with 10 or fewer teeth were at increased risk of CHD compared with men with 25 or more teeth (relative risk = 1.67; 95% confidence interval, 1.03 to 2.71), after adjustment for standard CHD risk factors. Among men without pre-existing periodontal disease, no relationship was found (relative risk = 1.11; 95% confidence interval, 0.74 to 1.68). The associations were only slightly attenuated after we controlled for dietary factors. No overall associations were found between periodontal disease and coronary heart disease. Tooth loss may be associated with increased risk of CHD, primarily among those with a positive periodontal disease history; diet was only a small mediator of this association.
Adult↗
Intake of carotenoids and retinol in relation to risk of prostate cancer.
BACKGROUND: Several human studies have observed a direct association between retinol (vitamin A) intake and risk of prostate cancer; other studies have found either an inverse association or no association of intake of beta-carotene (the major provitamin A) with risk of prostate cancer. Data regarding carotenoids other than beta-carotene in relation to prostate cancer risk are sparse. PURPOSE: We concluded a prospective cohort study to examine the relationship between the intake of various carotenoids, retinol, fruits, and vegetables and the risk of prostate cancer. METHODS: Using responses to a validated, semiquantitative food-frequency questionnaire mailed to participants in the Health Professionals Follow-up Study in 1986, we assessed dietary intake for a 1-year period for a cohort of 47,894 eligible subjects initially free of diagnosed cancer. Follow-up questionnaires were sent to the entire cohort in 1988, 1990, and 1992. We calculated the relative risk (RR) for each of the upper categories of intake of a specific food or nutrient by dividing the incidence rate of prostate cancer among men in each of these categories by the rate among men in the lowest intake level. All P values resulted from two-sided tests. RESULTS: Between 1986 and 1992, 812 new cases of prostate cancer, including 773 non-stage A1 cases, were documented. Intakes of the carotenoids beta-carotene, alpha-carotene, lutein, and beta-cryptoxanthin were not associated with risk of non-stage A1 prostate cancer; only lycopene intake was related to lower risk (age- and energy-adjusted RR = 0.79; 95% confidence interval [CI] = 0.64-0.99 for high versus low quintile of intake; P for trend = .04). Of 46 vegetables and fruits or related products, four were significantly associated with lower prostate cancer risk; of the four--tomato sauce (P for trend = .001), tomatoes (P for trend = .03), and pizza (P for trend = .05), but not strawberries--were primary sources of lycopene. Combined intake of tomatoes, tomato sauce, tomato juice, and pizza (which accounted for 82% of lycopene intake) was inversely associated with risk of prostate cancer (multivariate RR = 0.65; 95% CI = 0.44-0.95, for consumption frequency greater than 10 versus less than 1.5 servings per week; P for trend = .01) and advanced (stages C and D) prostate cancers (multivariate RR = 0.47; 95% CI = 0.22-1.00; P for trend = .03). No consistent association was observed for dietary retinol and risk of prostate cancer. CONCLUSIONS: These findings suggest that intake of lycopene or other compounds in tomatoes may reduce prostate cancer risk, but other measured carotenoids are unrelated to risk. IMPLICATIONS: Our findings support recommendations to increase vegetable and fruit consumption to reduce cancer incidence but suggest that tomato-based foods may be especially beneficial regarding prostate cancer risk.
Adult↗
Deaths and injuries caused by land mines in Mozambique.
Land mines in Mozambique are still causing death and injuries years after the initial dispute. Since 1980, 3400 people have had an amputation because of land mine injuries. However, there are no direct estimates of the number of deaths or casualties which are not treated in hospitals. In March, 1994, a medical team assembled by Physicians for Human Rights (PHR) conducted household surveys in the province of Manica and in the sub-district of Metuchira, province of Sofala. The object was to assess the frequency and severity of injuries and mortality caused by land mines in the civilian population. We found ratios of 8.1 and 16.7 casualties per 1000 living people in Manica and Metuchira, respectively. The prevalence of amputees was 3.2 per 1000 in Manica, and 2.3 in Metuchira. These figures are several folds higher than suggested by hospital data. The case fatality rate was 48%. Most of the victims were civilians (68%) and were injured by antipersonnel mines (81%). 16% of victims were women, and 7% were under 15 years of age. Our results suggest that the impact of land mines is substantially higher than originally thought.
Adolescent↗
Body size and fat distribution as predictors of coronary heart disease among middle-aged and older US men.
Obesity, android fat distribution, and other anthropometric measures have been associated with coronary heart disease in long-term prospective studies. However, fluctuations in weight due to age-related hormonal changes and changes in lifestyle practices may bias relative risk estimates over a long follow-up period. The authors prospectively studied the association between body mass index (BMI) (kg/m2), waist-to-hip ratio, and height as independent predictors of incident coronary heart disease in a 3-year prospective study among 29,122 US men aged 40-75 years in 1986. The authors documented 420 incident coronary events during the follow-up period. Body mass index, waist-to-hip ratio, short stature, and weight gain since age 21 were associated with an increased risk of coronary heart disease. Among men younger than 65, after adjusting for other coronary risk factors, the relative risk was 1.72 (95% confidence interval (CI) 1.10-2.69) for men with BMI of 25-28.9, 2.61 (95% CI 1.54-4.42) for BMI of 29.0-32.9, and 3.44 (95% CI 1.67-7.09) for obese men with BMI > or = 33 compared with lean men with BMI < 23.0. Among men > or = 65 years of age, the association between BMI and risk of coronary heart disease was much weaker. However, in this age group, the waist-to-hip ratio was a much stronger predictor of risk (relative risk = 2.76, 95% CI 1.22-6.23 between extreme quintiles). These results suggest that for younger men, obesity, independent of fat distribution, is a strong risk factor for coronary heart disease. For older men, measures of fat distribution may be better than body mass index at predicting risk of coronary disease.
Adipose Tissue↗