Secular trends in body mass in the United States, 1960-1980

A Female Career in Research

After a long career at the National Center for Health Statistics, I retired and joined the Stanford Prevention Research Center as an unpaid associate. I was once described by a former US Food and Drug Administration commissioner as "one of the great epidemiologists." The chair of the Harvard nutrition department, speaking on National Public Radio, once described my research as "rubbish." Both may be exaggerations. Here I address some of the events that led to these contrasting descriptions. I also address the extent to which the so-called Matilda effect may have influenced my career. Are women in science on an equal footing with men? The Matilda effect suggests not. Unlike the Matthew effect for scientists, whereby those of higher prestige accrue a disproportionate share of recognition and rewards, the Matilda effect proposes that women scientists are systematically undervalued and underrecognized. I could never get a faculty job and was often treated like an underling. Nonetheless I persevered to publish highly cited research on several high-profile and sometimes controversial topics. Though overt sexism in science and workplaces has diminished over the course of my career, progress toward eliminating unconscious bias has been slower. The Matthew and Matilda effects are still powerful forces that distort incentives and rewards in science. Expected final online publication date for the Annual Review of Nutrition, Volume 42 is August 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Biological Well-Being during the "Economic Miracle" in Spain: Height, Weight and Body Mass Index of Conscripts in the City of Madrid, 1955-1974

Typifying historical populations using anthropometric indicators such as height, BMI and weight allows for an analysis of the prevalence of obesity and malnutrition. This study evaluates secular changes in height, weight and body mass for men cohorts at 21 years old, born between 1934 and 1954 who were called up between 1955 and 1974, in the city of Madrid, Spain. In this study we prove the hypothesis that anthropometric variables increase thanks to improvement in diet and significant investments in hygiene and health infrastructure during the 1960s. The results of our analysis show a positive secular change in the trends for height (an increase of 4.67 cm), weight (6.400 kg) and BMI (0.90 Kg/m2), the result of a recovery in standards of living following the war and the autarchy of the 1940s. We also observed a slight trend towards obesity and a reduction in underweight categories at the end of the period is also observed. In conclusion, the secular trends of anthropometric variables in the city of Madrid reflect the recovery of living standards after the deterioration of the nutritional status suffered during the Spanish Civil War (1936-1939) and the deprivation of the autarchic period.

APOL1 renal risk variants are associated with obesity and body composition in African ancestry adults: An observational genotype-phenotype association study

ABSTRACT

While increased obesity prevalence among persons of African ancestry (AAs) compared to persons of European ancestry (EAs) is linked to social, environmental and behavioral factors, there are no gene variants that are common and significantly associated with obesity in AA populations. We sought to explore the association between ancestry specific renal risk variants in the apolipoprotein L1 (APOL1) gene with obesity related traits in AAs.We conducted a genotype-phenotype association study from 3 electronic medical record linked cohorts (BioMe Biobank, BioVU, nuGENE); randomized controlled trials (genetic testing to understand and address renal disease disparities) and prospective cohort study (Jackson Heart Study). We analyzed association of APOL1 renal risk variants with cross-sectional measures of obesity (average body mass index (BMI), and proportion of overweight and obesity) and with measures of body composition (in Jackson Heart Study).We had data on 11,930 self-reported AA adults. Across cohorts, mean age was from 42 to 49 years and percentage female from 58% to 75.3%. Individuals who have 2 APOL1 risk alleles (14% of AAs) have 30% higher obesity odds compared to others (recessive model adjusted odds ratio 1.30; 95% confidence interval 1.16-1.41; P = 2.75 × 10-6). An additive model better fit the association, in which each allele (47% of AAs) increases obesity odds by 1.13-fold (adjusted odds ratio 1.13; 95% confidence interval 1.07-1.19; P = 3.07 × 10-6) and increases BMI by 0.36 kg/m2 (∼1 kg, for 1.7 m height; P = 2 × 10-4). APOL1 alleles are not associated with refined body composition traits overall but are significantly associated with fat free mass index in women [0.30 kg/m2 increment per allele; P = .03].Thus, renal risk variants in the APOL1 gene, found in nearly half of AAs, are associated with BMI and obesity in an additive manner. These variants could, either on their own or interacting with environmental factors, explain a proportion of ethnic disparities in obesity.

Secular trends for skinfolds differ from those for BMI and waist circumference among adults examined in NHANES from 1988-1994 through 2009-2010

BACKGROUND

Although the prevalence of a body mass index [BMI (in kg/m²)] ≥30 has tripled among US adults since the 1960s, BMI is only moderately correlated with body fatness. Because skinfolds can more accurately estimate body fatness than can BMI, it is possible that skinfolds could be useful in monitoring secular trends in body fatness.

OBJECTIVE

We examined whether there were similar secular trends for skinfolds (triceps and subscapular), BMI, and waist circumference between US adults.

DESIGN

This study was an analysis of 45,754 adults who participated in the NHANES from 1988-1994 through 2009-2010. Approximately 19% of the subjects were missing ≥1 skinfold-thickness measurement. These missing values were imputed from other characteristics.

RESULTS

Trends in mean levels and in the prevalence of high levels of the 4 body size measures were fairly similar between men, with mean levels increasing by ≥5% from 1988-1994 through 2009-2010. Slightly larger increases were seen in women for BMI and waist circumference (7-8%), but trends in skinfolds were markedly different. The mean triceps skinfold, for example, increased by 2 mm through 2003-2004, but subsequently decreased so that the mean in 2009-2010 did not differ from that in 1988-1994. Compared with obese women in 1988-1994, the mean BMI of obese women in 2009-2010 was 1 higher, but mean levels of both skinfolds were 5-10% lower.

CONCLUSIONS

Although there were fairly similar trends in levels of BMI, waist circumference, and skinfold thicknesses in men in the United States from 1988-1994 through 2009-2010, there were substantial differences in women. Our results indicate that it is unlikely that skinfold thicknesses could be used to monitor trends in obesity.

Standards and classification: a perspective on the 'obesity epidemic'

In this paper I critique the increasing standardization of obesity. Specifically, I consider two 'definitional turns': the way language has been standardized to such an extent that it obscures uncertainty and variation, and the appearance of objectivity through quantification and standardized measurement. These, I suggest, have fostered a simplified picture of obesity, promoting the classification of weight and thereby facilitating the emergence of the 'obesity epidemic'. These definitional turns fail to acknowledge the distinctions between fat and mass and intraclass variation within weight categories. A consequence of this process of simplification has been the erroneous application of population level information to individuals in a clinical context, with potentially harmful results.

Associations of Body Mass and Body Fat Distribution with Parity Among African-American and Caucasian Women: The CARDIA Study

Associations of parity with body fat and its distribution are poorly understood; therefore, we examined the relationships between parity and obesity in young adult women. Body mass index (BMI), skin-folds, and waist-hip ratio were compared in 1452 African-American and 1268 Caucasian nonpregnant women aged 18 to 30, adjusting for age (where no age-parity interactions were present), education, physical activity (assessed by questionnaire) and fitness (assessed by graded exercise test), dietary fat intake, alcohol and smoking. Adjusted mean BMI was significantly higher in African-American women aged 25-30 years with three or more children (28.5 kg/m2) than in those with two (27.0 kg/m2), one (26.2 kg/m2), or no children (26.3 kg/m2). Similar trends were found in Caucasians (BMI = 23.3, 23.4, 23.7, 25.0 kg/m2 for parity = 0, 1, 2, > or = 3, respectively), but the mean BMI was significantly higher in African Americans in each parity group. The association between BMI and parity was not present among women 18-24 years of age. Skinfolds were directly associated with parity in African Americans only. Waist-hip ratios were generally lower among nulliparous than parous women in both ethnic groups; race differences were present only among nulliparas. In conclusion, parity was associated with BMI in women aged 25 to 30 years but did not explain ethnicity-related differences in body mass.

Management of upper extremity injuries in obese patients

Upper extremity injuries are more prevalent in obese people than in nonobese people after low-energy falls. Because splinting and casting are inefficient methods of stabilization in the setting of obesity, internal fixation provides stability for mobilization and realignment. Morbid obesity adversely affects positioning, surgical exposures, and complications associated with operative fixation. Avoiding short cuts and complications, morbidly obese patients should be able to return to normal functioning.

The timing of the rise in U.S. obesity varies with measure of fatness

There are several ways to measure fatness and obesity, each with its own strengths and weaknesses. The primary measure for tracking the prevalence of obesity has historically been body mass index (BMI). This paper compares long-run trends in the prevalence of obesity when obesity is defined using skinfold thickness instead of BMI, using data from the full series of U.S. National Health Examination Surveys. The results indicate that when one uses skinfold thickness rather than BMI to define obesity, the rise in the prevalence of obesity is detectable 10-20 years earlier. This underscores the importance of examining multiple measures of fatness when monitoring or otherwise studying obesity.

A Review of the Relationship Between 100% Fruit Juice Consumption and Weight in Children and Adolescents

Studies assessing a relationship between consumption of 100% fruit juice by children and adolescents and weight are contradictory. The purpose of this review was to assess the 9 cross-sectional and 12 longitudinal studies that have looked at this association. Of the 9 cross-sectional studies reviewed, only 3 reported any association. Those studies used small, local convenience samples of preschool children; furthermore, selection criteria were not well defined. One found that preschool children consuming ≥ 12 fluid oz/day of 100% fruit juice had a higher prevalence of overweight than those who consumed less than 12 oz/day (32% vs 9%). Later, a separate study showed that this relationship held only for apple juice. Another study demonstrated an association of overweight and energy from juice. These 3 studies were not nationally representative. Only 3 of the longitudinal studies showed an association between 100% fruit juice consumption and weight; 1 found an association only in adolescent girls, and 2 reported an association in children who were already overweight. None of the longitudinal studies was nationally representative, but 5 had sample sizes of at least 1000, 2 were ethnically diverse, and 3 had geographically separate sites, suggesting that the findings could be applicable to wider populations. Based on the currently available evidence, it can be concluded that there is no systematic association between consumption of 100% fruit juice and overweight in children or adolescents. Data do support consumption of 100% fruit juice in moderate amounts and suggest that consumption of 100% fruit juice may be an important strategy to help children meet the current recommendations for fruit.

Diabetes mellitus in the Hispanic/Latino population: an increasing health care challenge in the United States

The prevalence of diabetes in the U.S. Hispanic population has grown to epidemic proportions. The prevalence of diagnosed diabetes in Hispanics is 1.9 times higher than that in Caucasians. Diabetes is diagnosed at an earlier age, and, for a multiplicity of reasons, Hispanics suffer from higher rates of diabetic complications and mortality. The etiology for the higher prevalence of diabetes and its complications is not clear, but it is thought to be related to genetic and environmental factors. In this manuscript, we review recent epidemiologic information on the prevalence, pathophysiology, and complications of diabetes, as well as the recommendations for the management of Hispanics with type 2 diabetes.

Forecasting the obesity epidemic in the aging U.S. population

OBJECTIVE

The objective was to forecast BMI distribution in the U.S. population along with demographic changes based on past race-, sex-, and birth cohort-specific secular trends.

RESEARCH METHODS AND PROCEDURES

We compiled data from 44,184 subjects from 4 National Health and Nutrition Examination Surveys (NHANES; 1971 to 2004). By race and sex, we fit regression models to create smoothed mean BMI curves by age for 1970 to 2010. Linking corresponding birth cohorts across age- and year-specific mean BMI projections, we estimated the trajectory of relative BMI throughout each cohort's lifetime. These projections were validated using actual cohorts in the Nurses' Health Study and Health Professionals Follow-up Study. Combined with U.S. census, we predicted BMI distributions in 2010 and examined the joint impact of the obesity epidemic and population aging.

RESULTS

BMI secular trends in the past 3 decades differ significantly by birth cohort, sex, and race. If these trends continue, the prevalence of obesity is expected to reach 35%, 36%, 33%, and 55% in 2010 among white men, white women, black men, and black women, respectively, far from the Healthy People 2010 goal of 15%. Such forecasts translate into 9.3 million more obese adults 20 to 74 years of age than in 2000, 8.3 million of whom would be 50 years of age or older, and 8.5 million of whom would be white. The mean age among obese men and women is also expected to rise from 47 to 49 years among whites and from 43 to 44 years among blacks.

DISCUSSION

As the baby boom generation approaches retirement age, the continuing obesity epidemic signals a likely expansion in the population with obesity-related comorbidities. A framework to combine BMI and demographic trends is essential in evaluating the burden and disparity associated with the epidemic in the aging U.S. population.

Fifteen-year time trends in energy and macronutrient intake in German children and adolescents: results of the DONALD study

The DONALD study (Dortmund Nutritional and Anthropometric Longitudinally Designed study) gives the opportunity to evaluate long-term food and nutrient intake data on the basis of 3 d weighed dietary records of infants, children and adolescents since 1985. In this paper, we examine changes in energy and macronutrient intakes (protein, fat, saturated, mono- and polyunsaturated fatty acids, carbohydrates and added sugars) of 795 2–18-year-old subjects between 1985 and 2000 (4483 records). No significant changes in intakes of energy and of protein, polyunsaturated fatty acids and added sugars (as % energy intake, E %) were found. Fat intake decreased significantly in all age groups (between -0·20 and -0·26 E %/year), as well as intake of saturated fatty acids (between -0·11 and -0·14 E %/year) and monounsaturated fatty acids (between -0·07 and -0·014 E %/year). This decline was compensated for by a significant increase in carbohydrate intake (between +0·18 and +0·27 E %/year). The changes in macronutrient intake were mainly due to a decreased consumption of fats–oils (between -0·29 and -1·26 g/year) and meat–fish–eggs (between -0·21 and -2·92 g/year), whereas consumption of bread–cereals (between +0·12 and +2·42 g/year) and potatoes–pasta–rice (between +0·15 and +2·26 g/year) increased slightly. However, since recommended fat intake and fatty acid composition was not reached at the end of the study period by far, further efforts will be necessary to improve macronutrient composition and to stabilize favourable dietary habits.

Temporal changes in the physical fitness of US Army recruits

This article defines physical fitness and then reviews the literature on temporal trends in the physical fitness of new US Army recruits. Nineteen papers were found that met the review criteria and had published recruit fitness data from 1975 to 2003. The limited data on recruit muscle strength suggested an increase from 1978 to 1998 (20-year period). Data on push-ups and sit-ups suggested no change in muscular endurance between 1984 and 2003 (19-year period). Limited data suggested that maximal oxygen uptake (VO2max) [mL/kg/min] of male recruits did not change from 1975 to 1998 (23-year period), while there was some indication of a small increase in female recruit VO2max in the same period. On the other hand, slower times on 1-mile (1.6km) and 2-mile (3.2km) runs indicate declines in aerobic performance from 1987 to 2003 (16-year period). The apparent discrepancy between the VO2max and endurance running data may indicate that recruits are not as proficient at applying their aerobic capability to performance tasks, such as timed runs, possibly because of factors such as increased bodyweight, reduced experience with running, lower motivation and/or environmental factors. Recruit height, weight and body mass index have progressively increased between 1978 and 2003 (25-year period). Both the body fat and fat-free mass of male recruits increased from 1978 to 1998 (20-year period); however, body composition data on female recruits did not show a consistent trend. In this same time period, the literature contained little data on youth physical activity but there was some suggestion that caloric consumption increased. This article indicates that temporal trends in recruit fitness differ depending on the fitness component measured. The very limited comparable data on civilian populations showed trends similar to the recruit data.

Age-dependent changes in body size of Greek boys from 1982 to 2002

OBJECTIVE

The prevalence of childhood obesity has been rising during the past decades in many parts of the world, including Greece. The dispersion of these trends across age, however, is less clear. The aim of this study was to examine the relationship between age and 20-year changes in anthropometric characteristics of Greek boys.

RESEARCH METHODS AND PROCEDURES

A total of 204 and 106 boys 9 years old, 163 and 274 boys 12 years old, and 161 and 240 boys 15 years old were randomly recruited in 1982 and 2002, respectively, throughout the county of Iraklio, Crete, Greece. Height, weight, and BMI were measured.

RESULTS

Contemporary 9 and 12 year olds were taller than their peers in 1982 (+2.9% and +1.2%, respectively; p < 0.005), but this was not the case for 15 year olds (-0.8%; p = 0.083). Body weight and BMI were higher now than in the 1980s, and this held true for all age groups (p < 0.001). Increases in weight also showed a decline with advancing age (+17.4%, +13.9%, and +4.0% for 9, 12, and 15 year olds, respectively), whereas BMI changes were similar for those 9 and 12 years of age (approximately 10.5%), but were almost 2-fold higher than in 15 year olds (+5.5%).

DISCUSSION

Contemporary boys are taller, heavier, and have higher BMI values than their peers in 1982, but the magnitude of these increases gradually declines with advancing age. Rates of increase in BMI, however, seem to have greatly accelerated compared with previous decades.

Changing relationships of obesity and dyslipidemia in Greek children: 1982-2002

BACKGROUND

The prevalence of childhood overweight and obesity has been increasing rapidly during the past decades in many parts of the world. Less is known with respect to the effects of increasing adiposity on blood lipid profile. The present study was designed to examine the influence of adiposity on secular trends in anthropometric characteristics and plasma lipids of Greek children.

METHODS

A total of 419 and 374 boys with normal body weight and 109 and 246 boys with abnormal body weight (overweight and obese) were randomly recruited in 1982 and 2002, respectively (aged 12.1 +/- 0.1 years). Height, weight, body mass index (BMI, kg/m(2)), Rohrer index (kg/m(3)), plasma total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), triglyceride (TG), TC/HDL-C ratio, and LDL-C/HDL-C ratio were determined.

RESULTS

Temporal changes in weight (positive), BMI (positive), HDL-C (negative), and cholesterol ratios (positive) were greater among overweight and obese vs. normal-weight boys (P < 0.05), while those for height (positive), LDL-C (positive), TG (positive), and TC (no change) were of similar magnitude. The increase in Rohrer index since 1982 failed to reach significance for children with normal body weight (P = 0.077) but did so for overweight and obese subjects (P = 0.027).

CONCLUSIONS

These results indicate that secular increases in measures of fatness and adverse changes in plasma lipids were more pronounced among overweight and obese children than among normal-weight individuals, although qualitatively similar shifts were observed across the entire population.

Obesity prevention in children: opportunities and challenges

OBJECTIVE

Longitudinal survey data from a number of countries confirm that the number of overweight children continues to increase at alarming rates, and even developing countries are experiencing a rise in their overweight population. There is ample consensus that prevention strategies are essential to turn the tide of the obesity epidemic, and yet there are still relatively few proven prevention approaches for children. This paper briefly discusses some of the common features of childhood obesity prevention programs, focusing on the experience in the US and Canada.

APPROACH

Most prevention programs include at least one of the following components: dietary changes, physical activity, behavior and social modifications, and family participation. School-based prevention programs may also include elements related to the school environment and personnel. Primary prevention programs cannot usually restrict caloric intake, but may effectively reduce the energy intake by reducing the energy density of foods, increasing offering of fresh fruits and vegetables, using low-calorie versions of products, and reducing offering of energy-dense food items. Physical activity interventions have recently focused more on reducing inactive time, particularly television viewing. Results from recent studies have reported success in reducing excess weight gain in preadolescents by restricting TV viewing.

SUMMARY

Integrating all the activities of a multi-component prevention intervention, and delivering and sustaining it in different environments, continues to be a major challenge for health professionals as well as for parents, educators, and children themselves. Still, encouraging progress has been made in several areas, and the increased awareness of the problem of childhood obesity by all concerned will continue to foster our efforts in this area.

Are Kuwaitis getting fatter?

The purpose of the study is to compare temporal changes in BMI, overweight (BMI > 25 Kg/m2) and obesity (BMI > 30 Kg/m2) of two independent cross-sectional samples of Kuwaitis studied in 1980-81 and 1993-94. The earlier sample of 2067 (896 men and 1171 women) and the latter sample of 3435 (1730 men and 1705 women) adult Kuwaitis (aged > or = 18 years), were drawn from primary health care (PHC) clinics and studied for nutritional assessment and for prevalence of obesity in 1980-81 and 1993-94, respectively. Weight was measured in kilograms and height in meters to obtain the body mass index (BMI), which is the weight in kilograms divided by the height in meters squared (Kg/m2). BMI > 25 and > 30 Kg/m2 were classified as overweight and obesity, respectively. The results of the study show that mean BMI (Kg/m2) increased significantly (p < 0.001) by 10.0 and 6.2% (2.5 and 1.7 Kg/m2) among men and women, respectively. Prevalence of overweight and obesity (BMI > 25 and > 30 Kg/m2) increased by 20.6 and 15.4% and by 13.7 and 8.4% among men and women, respectively. After controlling for sociodemographic differences between the two study periods, mean BMI was 2.0 and 1.6 Kg/m2 higher in 1993-94 than in 1980-81 among men and women, respectively. Prevalence of overweight and obesity (BMI > 25 and > 30 Kg/m2) also increased among both genders between the two periods (OR = 2.1 , 95% CI 1.7-2.7 and OR = 1.9, 95% CI 1.5-2.4, for men and OR = 2.2, 95% CI 1.6-3.0 and OR = 1.4, 95% CI 2.2 CI 1.0-1.9, for women). It can be concluded that the BMI, prevalence of overweight and obesity increased among Kuwaitis between 1980-81 and 1993-94, probably due to the effects of modernization, affluence, increased food consumption and the concomitant changes to sedentary lifestyles. The rate of temporal changes in BMI and obesity were higher, by comparison, in Kuwait than in selected other countries.

Body composition and overweight prevalence in 1704 schoolchildren from 7 American Indian communities

BACKGROUND

Nationwide data on obesity prevalence in American Indian communities are limited.

OBJECTIVE

We describe the body composition and anthropometric characteristics of schoolchildren from 7 American Indian communities enrolled in the Pathways study, a randomized field trial evaluating a program for the primary prevention of obesity.

DESIGN

A total of 1704 children in 41 schools were enrolled in the study. Basic anthropometric measurements included weight, height, and triceps and subscapular skinfold thicknesses. Percentage body fat was estimated from bioelectrical impedance and anthropometric variables with the use of an equation developed and validated for this population.

RESULTS

The children's mean (+/- SD) age was 7.6 +/- 0.6 y, and their mean weight and height were 32.1 +/- 8.9 kg and 129.8 +/- 6.3 cm, respectively. Mean body mass index (BMI; in kg/m(2)) was 18.8 +/- 3.9, and mean percentage body fat was 32.6 +/- 6.8%. With the use of current Centers for Disease Control and Prevention reference values, 30.5% of girls and 26.8% of boys were above the 95th percentiles for BMI-for-age, and 21% of girls and 19.6% of boys were between the 85th and 95th percentiles. Although there was a wide range in BMI across study sites and for both sexes, the percentage of children with a BMI above the 95th percentile was consistently higher than the national averages in all communities studied and in both girls and boys.

CONCLUSIONS

Overweight can be documented in a substantial number of American Indian children by the time they reach elementary school. Despite differences in the prevalence of overweight observed among communities, rates are uniformly high relative to national all-race averages.

The secular trend in human physical growth: a biological view

Nutritionists and anthropometric historians alike are familiar with the secular trend-height and weight in adults, and the rate of physical development in children, increasing since at least the mid 19th century. The social conditions which drive this trend are of interest to anthropometric historians, but the underlying biology is also important. Here the trends for height, weight and menarcheal age are summarised and contrasted. In Northern Europe, adult height has largely stabilised, and the age of menarche has also settled at around 13 years, while weight continues to increase due to obesity. The increase in height from one generation to the next occurs mainly in the first 2 years of life, due to increases in leg length. The height trend has lasted for 150 years or more, i.e. for six generations, because the rate of catch-up from one generation to the next is biologically constrained to avoid the cost of too rapid catch-up.

Childhood obesity in Canada: a review of prevalence estimates and risk factors for cardiovascular diseases and type 2 diabetes

Childhood obesity in Canada has become increasingly prevalent over the past 2 decades. Despite inconsistencies regarding different anthropometric indicators, cut-offs, and reference populations, both regional and national investigations have revealed high numbers of overweight and obese children and adolescents. A number of risk factors and health consequences have been associated with increased levels of body fatness in youth. Specifically, risk factors for cardiovascular diseases (CVD) and type 2 diabetes are known to develop early in life and tend to emerge in clusters among overweight youngsters. Unhealthy lifestyle behaviours (i.e., physical inactivity), a genetic disposition, and a centralized body fat distribution, all contribute to increased risk. In order to prevent future generations of children from experiencing increased morbidity and mortality as overweight and obese adults, coordinated efforts at all levels (family, school, community, and government) must be established with a long-term commitment to promote healthy nutrition and physical activity behaviours in our youth.

Dopamine transporter genotype as a risk factor for obesity in African-American smokers

OBJECTIVE

To assess the association between a polymorphism related to dopamine function, dopamine transport (SLC6A3), and obesity in smokers.

RESEARCH METHODS AND PROCEDURES

Logistic regression was used to assess the relationship between this genetic polymorphism and obesity (body mass index > or = 30 kg/m(2)) from a sample of 510 smokers who smoked at least 10 cigarettes per day and who were participating in a study designed to examine genetic and nongenetic predictors of response to a pharmacological treatment.

RESULTS

The likelihood of obesity in African Americans (N = 90) with the 10/10 SLC6A3 genotype was 5.16 times that of African Americans with 9/9 or 9/10 SLC6A3 genotypes (odds ratio = 5.16, confidence interval = 1.60 to 16.65). There was no association of the SLC6A3 genotype with obesity for non-Hispanic whites (N = 420).

DISCUSSION

These results suggest that variants of the dopamine transporter gene may be related to obesity in African-American smokers. Possible mechanisms responsible for the association between dopamine transport and obesity in African-American smokers are discussed.

Comparison between body mass index, triceps skin fold thickness and mid-arm muscle circumference in Saudi adolescents

INTRODUCTION

Adolescence is an important period in an individualâs life. Overweight and obesity are fraught with several health problems even later in life. The objective of this study was to estimate the overweight, obesity, body fat and muscle content of Saudi adolescents as compared to a recognized reference population.

SUBJECTS AND METHODS

Data were collected from a sample of Saudi adolescents in Jeddah from 42 boys' and 42 girls' schools during the month of April 2000. Data collection was done by personal interviews to collect sociodemographic factors and by direct measurement of weight, height, triceps skin fold thickness (TSF) and mid-arm circumference (MAC). The 50th, 85th, and 95th percentiles (P50, P85 and P95) for body mass index (BMI) and triceps skin fold thickness (TSF) were taken, then the 50th, 90th, and 95th percentiles (P50, P90 and P95) for the mid-arm muscle circumference (MAMC) were calculated. These measurements were compared with corresponding values of the National Health and Nutrition Examination Survey I (NHANES I).

RESULTS

The P85 and P95 for BMI and TSF were higher for Saudi adolescents than the NHANES I and the difference was wider for P95. Conversely, there was a lower MAMC at P90 and P95 than the NHANES I reference population curves. The lower MAMC curves were less marked in girls than in boys. On the other hand, Saudi boys and girls showed on average similar body mass index indicated by BMI at P50, which was misleading, since those adolescents showing similar body mass index had more fatness than the average reference population indicated by TSF at P50, and less muscularity on average than reference population indicated by MAMC at P50.

CONCLUSION

Overweight and obesity with increased body fat content and decreased body muscle content appear to be widespread among Saudi adolescents even among those adolescents showing average body mass index. Public health interventions are required to improve quality of food, encourage physical activity and exercise, as well as correct the perception of appropriate body stature.

Update on cardiovascular disease in post-menopausal women

Cardiovascular disease (CVD), and in particular coronary artery heart disease (CAHD), is the leading cause of morbidity and mortality in women. Until recently, most of our knowledge about the pathophysiology of CVD in women - and, subsequently, management guidelines - were based on studies conducted mostly in men. While similar mechanisms operate to induce CVD in women and men, gender-related differences exist in the anatomy and physiology of the myocardium, and sex hormones modify the course of disease in women. Women, more than men, have their initial manifestation of CAHD as angina pectoris; are likely to be referred for diagnostic tests at a more advanced stage of disease, and are less likely than men to have corrective invasive procedures. The overall morbidity and mortality following the initial ischaemic heart event is worse in women, and the case fatality rate is greater in women than in men. Also, the relative impact of impaired vasoreactivity of the coronary artery, increased viscosity of the blood and dysregulation of automaticity and arrhythmia, is greater in women than in men. The most effective means of decreasing the impact of CVD on women's health is by an active approach from childhood to proper principles of healthcare in order to modify the contribution of specific risk factors. The latter include obesity, abnormal plasma lipid profile, hypertension, diabetes mellitus, cigarette smoking, sedentary lifestyle, increased blood viscosity, augmented platelet aggregability, stress and autonomic imbalance. The use of lipid-lowering drugs has not been adequately studied in women but reports from studies conducted mostly in men do predict an advantage also to women. Oestrogen deficiency after spontaneous or medically induced menopause is an important risk factor for CVD and CAHD. Observational and mechanistic data suggest a role for oestrogen replacement after menopause for primary, and possibly secondary, prevention of CVD. However, two recent prospective trials suggest that treatment de novo with hormone replacement of older post-menopausal women after an acute coronary event may not confer cardiovascular protection and may increase the risk of thromboembolic disease. Results of ongoing long-term studies may determine the beneficial role of hormone replacement versus potential risks involved with this treatment.

The relation between self-rated health, socioeconomic status, body mass index and disability pension among middle-aged men

The aim of this study was to assess the relations between self-rated health (SRH), socioeconomic status (SES), body mass index (BMI) and disability pension. Five birth-year cohorts of middle-aged male residents in Malmö, Sweden, were invited and 5313 with complete data constituted the cohort in this study. Each subject was followed for approximately 11 years. Of all subjects, 73% perceived their health as perfect and among obese men and blue collar workers, the corresponding figures were 67 and 68% respectively. The adjusted odds ratios for SRH less than perfect was 1.3 (CI: 1.1-1.7) for obese subjects and 1.7 (CI: 1.5-1.9) for blue collar workers. The interaction between low SES and obesity was estimated to 11% which was not statistically significant. The adjusted relative risks (RR) of disability pension was 3.3 for subjects with SRH less than perfect, 2.2 for blue collar workers and 2.0 for obese subjects, all statistically significant and only marginally less than the crude RR. Thus, SRH among middle-aged men was associated with obesity as well as low SES, but no evidence of synergism between obesity and low SES in relation to SRH was found. Furthermore, poor SRH in particular, but also low SES and obesity, independently predicted disability pension.

Secular increases in body fat percentage in male children of Zaragoza, Spain, 1980-1995

BACKGROUND

Data on temporal changes on total body fat percentage (TBF%) are scarce, and no such data are known to exist in Spain. The aim of our study was to describe secular increases in TBF% in male children and adolescents of Zaragoza, Spain, from 1980 to 1995.

METHODS

The samples analyzed in the present study have been included in two cross-sectional surveys conducted in 1980 and 1995. The samples selected for the 1980 and 1995 surveys comprised 1553 and 701 male children with ages ranging from 6.0 to 14.9 years. Weight, height, and four skinfold thicknesses were measured. From these measurements we have calculated TBF%.

RESULTS

Concerning body mass index (BMI), we have observed significant increases from 8.5 to 11.5 years, ranging in this age group from 0.80 to 1.45 kg/m(2). TBF% showed significant increases at all age groups, with percentage increases of 2.46% at 13.5 years and 6.03% at 11.5 years.

CONCLUSIONS

We have shown a secular increase in TBF% in children aged 6.0 to 15.0 years that is greater than the increase in BMI. The similarity of our findings for both relative weight and skinfold thickness, even with less significant differences for BMI, suggests that, in children of Zaragoza, Spain, adiposity has increased during the 1980-1995 period.

The genesis of atherosclerosis and risk factors: a review

Atherosclerosis constitutes the most common medical and surgical problem. This can be manifested clinically as stroke, coronary artery disease, or peripheral vascular disease. In the present review the microscopic appearance of the normal arterial wall, the definition of atherosclerosis and the five theories of atherogenesis are described. These are: the lipid theory, the hemodynamic theory, the fibrin incrustation theory, the nonspecific mesenchymal hypothesis and the response to injury hypothesis. Based on the above theories the sequence of events in atherogenesis is analyzed. The classification of the atherosclerotic lesions according to Stary (types I-VI) and their characteristics appear in a table. The epidemiology and the role of the following risk factors are presented in detail: age, sex, lipid abnormalities, cigarette smoking, hypertension, diabetes mellitus, physical inactivity, alcohol consumption, obesity, and hemostatic factors. In addition, less common genetically determined associations like homocystinuria, Tangier disease, Hutchinson-Gilford syndrome (progeria), Werner's syndrome, radiation induced atherosclerosis and the implications of Chlamydia pneumoniae on the arterial wall are discussed.

Genetic inheritance of body mass index in African-American and African families

Numerous studies have shown recessive major gene inheritance of body mass index (BMI) in white populations; few have examined the inheritance of BMI in the African-American population where obesity is more prevalent, nor in African populations where obesity is comparatively rare. To evaluate the inheritance of obesity in two different populations of African origin, we used segregation analysis to determine the transmission of BMI in 95 African-American families and 400 Nigerian families. Probands were selected from participants in the population-based International Collaborative Study on Hypertension in Blacks. Using class D regressive models, results from the segregation analysis of the African-American data showed evidence of a major gene effect on BMI. The Nigerian results were strikingly similar, with comparable estimates for the genotype frequencies and means and strong evidence for a major effect in the transmission of BMI. The high BMI allele frequency estimate of 24% is consistent with estimates in other studies, but the mode of transmission appeared codominant, which differs from studies involving predominantly white populations. In the Nigerian analysis, however, the probability of a high BMI homozygote parent transmitting a low BMI allele to his/her offspring was significantly different from the Mendelian expectation of zero (estimated tau(BB) = 0.45), suggesting that additional complexities exist in the major gene inheritance of BMI in this population. The strong similarity of the genotype frequencies and means obtained from the African-American and Nigerian samples suggests that a common codominant major gene effect may contribute to the variation in BMI in both populations.

Radiographically defined osteoarthritis of the hand and knee in young and middle-aged African American and Caucasian women

Osteoarthritis (OA) has been characterized as a slowly evolving degenerative disease affecting cartilage and bone, with a multifactorial etiology that may differ depending on the joint site. Because OA has been considered a disease of the elderly, few population-based studies have examined its frequency and characteristics in persons under the age of 45.

OBJECTIVE

In this cross-sectional study, we examined X-rays of both knees and the dominant hand in a population of younger black and white pre- and perimenopausal women in southeastern Michigan (N = 1053) for evidence of osteoarthritis, and reported these outcomes according to the risk factors of age, body size, injury, and smoking behavior.

DESIGN

Sixteen joints of the dominant hand as well as both knee joints (weight bearing) were evaluated using the Kellgren and Lawrence Atlas of Standard Radiographs of Arthritis.

RESULTS

By age 40, radiographically-defined osteoarthritis emerges in both the hands and knees. These age characteristics are observed in both black and white women, however prevalence of knee OA was higher in black females (23.1%) compared with white females (8.5%), and although prevalence of hand OA was more comparable between black (25.5%) and white females (19.2%), the joint sites affected differed. The major risk factors reported in studies of older populations are present in this younger population where OA is newly emerging.

CONCLUSIONS

This study provides strong evidence that primary prevention of OA must be implemented in young adulthood to curtail the emergence of radiographically-defined OA at the mid-life.

Dietary fat patterns in urban African American women

The purpose of this study was to describe the scope of fatty food preferences of urban African American women and to examine factors associated with the selection of high fat foods. A volunteer sample of urban African American women church-goers were invited for dietary and risk factor screening at health fairs held following Sunday services. A standardized instrument, the Fat Intake Scale (FIS), was administered primarily by dietitians to estimate dietary fat intake and usual food choices. A sum score of 25 or more is thought to be associated with higher fat and cholesterol intake. As a validation of the FIS, a 24-hour recall was administered to a subsample. Sociodemographics, smoking status and comorbidity were assessed by self-report. Body weight, height, and total blood serum cholesterol were assessed using standardized measurement techniques. In the 521 participating women, 61% were classified as obese based on national reference norms for body mass index (BMI). More than 81% had an FIS of 25 or greater. On multiple logistic regression analysis, significant predictors of a higher fat diet (FIS > or = 25) included age greater than 45 years, obesity, and the absence of comorbidity. These findings suggest that there are independent predictors of selection of a diet high in fat. This has implications for planning and targeting community-based nutrition interventions for African American women who exhibit among the highest rates of obesity in the U.S. and who suffer an excess burden of obesity-related diseases.

Prevalence of multiple cardiovascular disease risk factors among women in the United States, 1992 and 1995: the Behavioral Risk Factor Surveillance System

We sought to examine the prevalence of self-reported multiple cardiovascular disease (CVD) risk factors (hypertension, high blood cholesterol, diabetes, overweight, and current smoking) among women in 1992 and 1995 in the United States using data from the Behavioral Risk Factor Surveillance System. In 1992, 37.5%, 34.4%, and 28.1% of women had zero, one, and two or more of the five risk factors, respectively. In 1995, the respective estimates were 35.5%, 34.3%, and 30%. In both years, the prevalence of two or more risk factors increased with age, decreased with educational level, was higher among black women (lowest among Hispanic women and women of other ethnic groups), and higher among women reporting cost as a barrier to healthcare. The percentage of women with two or more risk factors was higher in 1995 than in 1992 for 35 of 48 states, being statistically significant for 7 states. The percentage of women with at least two risk factors was not significantly lower in 1995 than in 1992 for any state. A higher percentage of women reported having multiple CVD risk factors in 1995 compared with 1992. A multifactorial approach to primary prevention and risk factor reduction should be encouraged to help reduce the prevalence and burden of CVD among women.

Trends in growth and obesity in ethnic groups in Britain

AIM

To estimate trends in growth for 5 to 11 year old ethnic minority and inner city children and comparative representative samples from 1983 to 1994.

DESIGN

Mixed longitudinal.

SUBJECTS

At each of six surveys, more than 2000 inner city white, 1500 Urdu or Punjabi speaking, 5000 English representative white, 3000 Scottish representative white, and around 1000 Afro-Caribbean, 500 falling to 300 Gujarati speaking, and 260 increasing to 300 other Indian children.

MAIN OUTCOME MEASUREMENTS

Height, weight for height, and triceps skinfold thickness.

RESULTS

Height increased in all inner city groups by approximately 1.5 cm, but group differences were maintained. Trends in triceps skinfold varied, but increased by 4-12% in Indian subcontinent girls. Weight for height increased generally. Inner city white children showed conflicting trends in weight for height and fatness.

CONCLUSIONS

Afro-Caribbean children are maintaining their tall, slim build, but other groups emphasise the diversity of obesity patterns in a multi-ethnic society, with a predominant trend towards greater obesity. Monitoring of these groups should continue.

Secular trends of weight, height and obesity in cohorts of young Portuguese males in the District of Lisbon: 1960-1990

OBJECTIVE

To examine the secular trend of weight, height and obesity among young Portuguese males at the time of military inspection for national conscription purposes in the region of Lisbon, during the last thirty years.

DESIGN

Cross-sectional study, based on the review of military census files.

SETTING

Military selection centre of Lisbon.

SUBJECTS AND METHODS

In Portugal, military service is obligatory and medical inspections are carried out every year on males at the age of twenty. For study purposes, representative samples were taken from the young male population undergoing inspection for the Armed Forces on a five year basis, between 1960 and 1990 in the region of Lisbon. Weight and height were evaluated by a trained team, using standard measurement instruments and procedures.

RESULTS

A progressive and significant increase in weight, height and BMI of the young male population was found between 1960 and 1990. For certain variables the increase was also statistically significant within a five-year period, as it was the case for height between 1965-1980 and for weight between 1985-1990. The increase in BMI experienced some minor fluctuation along the reference period, however, it was statistically significant between 1985-1990. The increase in weight and in BMI was greater in the highest percentiles and particularly noticeable between 1985 and 1990. The percentage of young males with BMI over 25 kg/m2 was of 8.1% in 1960 and of 18.0% in 1990, while those having a BMI over 27 kg/m2 varied between 3.6% and 6.4% in the same period, respectively. The percentage of young adult males with BMI higher than 25 kg/m2 doubled between 1960 and 1990.

Impact of multiple risk factor profiles on determining cardiovascular disease risk

BACKGROUND

We examined the association between clustering of risk factors and the risk for coronary heart disease, stroke, and all-cause mortality.

METHODS

Data from the First National Health and Nutrition Examination Survey Epidemiologic Follow-Up Study (N = 12,932) were used to estimate the relative risk for coronary heart disease (N = 2,255), stroke (N = 929), and death from any cause (N = 4,506) by the number of cardiovascular disease risk factors present. Risk factors included current smoking, overweight, hypertension, high blood cholesterol, and diabetes.

RESULTS

The proportions of respondents with 0, 1, 2, 3, or > or = 4 risk factors were 25.0, 32.8, 27.8, 12.3, and 2.1%, respectively. Relative risks for coronary heart disease associated with having 1, 2, 3, and > or = 4 risk factors were 1.6 (95% confidence interval [CI] 1.4, 1.9), 2.2 (95% CI 1.9, 2.6), 3.1 (95% CI 2.6, 3.6), and 5.0 (95% CI 3.9, 6.3), respectively. Relative risks for stroke associated with the same risk levels were 1.4 (95% CI 1.1, 1.8), 1.9 (95% CI 1.5, 2.4), 2.3 (95% CI 1.7, 3.0), and 4.3 (95% CI 3.0, 6.3), respectively. Similar results were observed for all-cause mortality.

CONCLUSIONS

Risk for cardiovascular disease and all-cause mortality increased substantially with each additional risk factor. This supports the continued need for primary prevention of cardiovascular disease risk factors.

Increasing prevalence of overweight among US low-income preschool children: the Centers for Disease Control and Prevention pediatric nutrition surveillance, 1983 to 1995

OBJECTIVE

To determine whether the prevalence of overweight in preschool children has increased among the US low-income population.

DESIGN

Analysis using weight-for-height percentiles of surveillance data adjusted for age, sex, and race or ethnicity.

SETTING

Data from 18 states and the District of Columbia were examined.

SUBJECTS

Low-income children <5 years of age who were included in the Centers for Disease Control and Prevention Pediatric Nutrition Surveillance System.

RESULTS

The prevalence of overweight increased from 18.6% in 1983 to 21.6% in 1995 based on the 85th percentile cutoff point for weight-for-height, and from 8.5% to 10.2% for the same period based on the 95th percentile cutoff point. Analyses by single age, sex, and race or ethnic group (non-Hispanic white, non-Hispanic black, and Hispanic) all showed increases in the prevalence of overweight, although changes are greatest for older preschool children.

CONCLUSION

Overweight is an increasing public health problem among preschool children in the US low-income population. Additional research is needed to explore the cause of the trend observed and to find effective strategies for overweight prevention beginning in the preschool years.

Nutrition, Activity, and Health in Children

This chapter reviews current understanding of the associations between physical activity and nutrition in children 1 to 10 years of age. In general, both undernutrition and overnutrition are accompanied by lower levels of physical activity than in controls. In children of normal nutritional status, an association between physical activity and body composition has been difficult to demonstrate. It is clear that levels of physical activity in children are responsive to the physical and social environments, as well as to a child's nutritional status. In children of normal nutritional status, the level of physical activity increases with age in young children and then decreases in early adolescence, and males tend to be more physically active than females in a given population. Although there is a perception that children are less physically active than they were in the past, trends in physical activity through time are not known.

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.

Seven-year trends in body weight and associations with lifestyle and behavioral characteristics in black and white young adults: the CARDIA study

OBJECTIVES

This study estimated the amount of weight change in a biracial cohort of young adults and the separate components attributable to time-related and aging-related changes, as well as identified possible determinants of weight change.

METHODS

In this population-based prospective study of 18- to 30-year-old African-American and White men and women, body weight and prevalence of overweight were measured from 1985/86 to 1992/93.

RESULTS

Average weight increased over the 7 years, increases ranging from 5.2 kg (SE = 0.2, n = 811) in White women to 8.5 kg (SE = 0.3, n = 882) in African-American women. Significant time-related increases in weight, ranging from 2.0 kg (SE = 1.0) in White women to 4.8 kg (SE = 1.0, n = 711) in African-American men, accounted for 40% to 60% of the average total weight gain. Aging-related increases were also significant, ranging from 2.6 kg (SE = 0.8, n = 944) in White men to 5.0 kg (SE = 1.1) in African-American women. The prevalence of overweight increased progressively in each group. Decreased physical fitness was most strongly associated with weight gain in both sexes.

CONCLUSIONS

The observed dramatic time-related weight gains, most likely due to secular (period-related) trends, are a serious public health concern.

Secular increases in relative weight and adiposity among children over two decades: the Bogalusa Heart Study

OBJECTIVE

To examine trends in relative weight and obesity among 5- to 24-year-olds between 1973 and 1994.

DESIGN

A panel design consisting of seven cross-sectional surveys of schoolchildren and three surveys of post-high-school subjects. Anthropometric measurements included height, weight, and subscapular and triceps skinfolds.

STUDY POPULATION

All schoolchildren residing in Ward 4 of Washington Parish, Louisiana, a biracial community, were considered eligible; participation rates were >80%. Young adults were eligible if they had participated previously as schoolchildren. A total of 26,371 examinations were performed on 11,564 persons.

RESULTS

During the study period, substantial increases in mean levels of weight (0.2 kg/y) and skinfold thickness (0.15 mm/y) were observed; these changes were independent of height, age, and other covariates. The prevalence of overweight, defined by the 85th percentile of weight-for-height in 1973 to 1974, increased approximately twofold by 1994. Although secular increases were seen both among boys and girls and among blacks and whites, the largest increases were seen among 19- to 24-year-olds. Furthermore, the yearly increases in relative weight and obesity during the latter part of the study period (1983 through 1994) were approximately 50% greater than those between 1973 and 1982.

CONCLUSIONS

The increasing prevalence of obesity in early life indicates a need for primary prevention. Additional study is needed to determine whether these trends are continuing to accelerate and to examine possible explanations, such as diet and physical activity, for these changes.

Measures of adiposity and coronary heart disease mortality in the Chicago Western Electric Company Study

Associations of body mass index (BMI), two measures of percent body fat derived from skinfolds, body weight adjusted for height, triceps and subscapular skinfolds, and their sum, with 22-year coronary heart disease (CHD) mortality were compared in 1707 white men ages 40-55 years at baseline (1958) and free of CHD and cancer in 1961 in the Western Electric Study. Because associations of adiposity measures with CHD mortality differed by length of follow-up, analyses were conducted separately for the first 14 years of follow-up and years 15 through 22. In Cox regression analyses, none of the adiposity measures was significantly related to CHD mortality for the first 14 years of follow-up. For years 15-22, all adiposity measures, except triceps skinfold, were significantly related with adjustment for age, as well as eight other covariates. These results indicate that a positive relation of adiposity to CHD risk may not become apparent until several years after the assessment of adiposity.

Trends in obesity differences by educational level in Spain

Our objective was to study the trend in differences in the frequency of obesity by educational level in the general population 20 to 64 years of age. We used data from two cross-sectional health surveys carried out in 1987 and 1993 in representative samples of the Spanish population. We investigated the relation between obesity and educational level during the periods 1987 and 1993, taking into account the main factors confounding the relation. We used, as setting, the National Health Interview Surveys representative of the whole Spanish population. In both men and women, the highest odds ratios (ORs) for obesity were observed at lower educational levels. These differences increased in women between 1987 and 1993, while they decreased in men during the same period. Evidence of increased educational differences in the frequency of obesity indicates that future studies should focus on the evaluation and monitoring of this trend in the population.

Plasma cholesterol and other cardiac risk factors in adolescent girls

The aim was to examine the effects of smoking, physical activity, and body mass on total cholesterol and high density lipoprotein cholesterol (HDL-C) in adolescent schoolgirls in Sydney, Australia. Body mass index (BMI) and waist to hip ratio (WHR) were determined in 144 girls aged 15 to 18 years. Total cholesterol (TC) and HDL-C were estimated on fingerprick blood and behavioural variables assessed by questionnaire. Prevalence of overweight (> 90th centile for BMI) was less in Australian adolescents than reported from the USA. Smokers had lower total cholesterol than non-smokers; this was partly explained by a lower HDL-C in the smokers. Physical activity was associated with a less atherogenic TC/HDL-C ratio. Girls with BMI > 90th centile had higher mean TC/HDL-C and apoprotein B than the group as a whole but those > 90th centile for WHR did not.

Body weight and mortality among women

BACKGROUND

The relation between body weight and overall mortality remains controversial despite considerable investigation.

METHODS

We examined the association between body-mass index (defined as the weight in kilograms divided by the square of the height in meters) and both overall mortality and mortality from specific causes in a cohort of 115,195 U.S. women enrolled in the prospective Nurses' Health Study. These women were 30 to 55 years of age and free of known cardiovascular disease and cancer in 1976. During 16 years of follow-up, we documented 4726 deaths, of which 881 were from cardiovascular disease, 2586 from cancer, and 1259 from other causes.

RESULTS

In analyses adjusted only for age, we observed a J-shaped relation between body-mass index and overall mortality. When women who had never smoked were examined separately, no increase in risk was observed among the leaner women, and a more direct relation between weight and mortality emerged (P for trend < 0.001). In multivariate analyses of women who had never smoked and had recently had stable weight, in which the first four years of follow-up were excluded, the relative risks of death from all causes for increasing categories of body-mass index were as follows: body-mass index < 19.0 (the reference category), relative risk = 1.0; 19.0 to 21.9, relative risk = 1.2; 22.0 to 24.9, relative risk = 1.2; 25.0 to 26.9, relative risk = 1.3; 27.0 to 28.9, relative risk = 1.6; 29.0 to 31.9, relative risk = 2.1; and > or = 32.0, relative risk = 2.2 (P for trend < 0.001). Among women with a body-mass index of 32.0 or higher who had never smoked, the relative risk of death from cardiovascular disease was 4.1 (95 percent confidence interval, 2.1 to 7.7), and that of death from cancer was 2.1 (95 percent confidence interval, 1.4 to 3.2), as compared with the risk among women with a body-mass index below 19.0. A weight gain of 10 kg (22 lb) or more since the age of 18 was associated with increased mortality in middle adulthood.

CONCLUSIONS

Body weight and mortality from all causes were directly related among these middle-aged women. Lean women did not have excess mortality. The lowest mortality rate was observed among women who weighed at least 15 percent less than the U.S. average for women of similar age and among those whose weight had been stable since early adulthood.