Resemblance for body mass index in families of obese African American and European American women

OBJECTIVE: We determined the levels of resemblance in body mass index (BMI) in large samples of families selected through obese African American and European American women. RESEARCH METHODS AND PROCEDURES: We examined correlations among relatives in 1,185 European American and African American families ascertained through age-matched obese women (BMI > or = 30 kg/m2). A subset of 801 families were ascertained through extremely obese women (BMI > or = 40 kg/m2). RESULTS: Parent-offspring and sibling correlations ranged from 0.19 to 0.15, suggesting a moderate level of heritability in both groups. Mean BMI values for female relatives were lower for European Americans than for African Americans even though probands were matched, perhaps because the European American relatives regress to a lower population mean. We found significantly higher family correlations for height in European Americans, suggesting greater environmental variability among African Americans for factors affecting growth and physical development. DISCUSSION: Our results suggest a similar level of heritability of BMI in families of obese African American and European American women. Other genetic studies will be needed to determine the extent to which the same or different genes and environmental conditions contribute to an overall similar heritability in the two racial groups.     

Associations of aging and birth cohort with body mass index in a biethnic cohort

OBJECTIVE: To examine associations of aging and birth cohort with body mass index (BMI) in a biethnic cohort. RESEARCH METHODS AND PROCEDURES: This was a longitudinal closed cohort study of 14,500 white and African-American men and women, 45 to 64 years of age, followed for 9 years. Aging was defined as the length of the interval in years between baseline and following visits. Birth cohort was defined by the year in which participants were born. Mixed model analyses were used to examine associations of aging, birth cohort, and BMI in four ethnicity-gender groups. RESULTS: We found that aging was associated with an increase in BMI in white and African-American men and women. The associations between aging and BMI were stronger in the younger birth cohorts. Except for white women, younger birth cohort was associated with a higher BMI. After adjusting for aging, birth cohort was associated with an increase in BMI of 0.1 kg/m(2) [95% confidence interval (95% CI): -0.1, 0.3] among white women. The corresponding values for African-American women, white men, and African-American men are 0.5 kg/m(2) (95% CI: 0.1, 0.9), 0.6 kg/m(2) (95% CI: 0.4, 0.8), and 0.6 kg/m(2) (95% CI: 0.2, 1.0), respectively. DISCUSSION: Our analyses show that, in all except white women, people in this age range who were born later have a higher BMI at the same attained age. In all groups, people who are born later gained more weight as they aged. In general, subjects ages 45 to 64 years gained weight as they aged 9 years.     

Ethnic differences in visceral adipose tissue and type 2 diabetes: Filipino, African-American, and white women

OBJECTIVE: To compare ethnic differences in visceral adipose tissue (VAT), assessed by computed tomography, and type 2 diabetes risk among 55- to 80-year-old Filipino, African-American, and white women without known cardiovascular disease. RESEARCH METHODS AND PROCEDURES: Subjects were participants in the Rancho Bernardo Study (n = 196), the Filipino Women's Health Study (n = 181), and the Health Assessment Study of African-American Women (n = 193). Glucose and anthropometric measurements were assessed between 1995 and 2002. RESULTS: African-American women had significantly higher age-adjusted BMI (29.7 kg/m(2)) and waist girth (88.1 cm) compared with Filipino (BMI, 25.5 kg/m(2); waist girth, 81.9 cm) or white (BMI: 26.0 kg/m(2); waist girth: 80.7 cm) women. However, VAT was significantly higher among Filipino (69.1 cm(3)) compared with white (62.3 cm(3); p = 0.037) or African-American (57.5 cm(3), p < 0.001) women. VAT correlated better with BMI (r = 0.69) and waist (r = 0.77) in whites, compared with Filipino (r = 0.42; r = 0.59) or African-American (r = 0.50; r = 0.56) women. Age-adjusted type 2 diabetes prevalence was significantly higher in Filipinas (32.1%) than in white (5.8%) or African-American (12.1%) women. Filipinas had higher type 2 diabetes risk compared with African Americans [adjusted odds ratio, 2.30; 95% confidence interval (CI), 1.09 to 4.86] or whites (adjusted odds ratio, 7.51; 95% CI, 2.51 to 22.5) after adjusting for age, VAT, exercise, education, and alcohol intake. DISCUSSION: VAT was highest among Filipinas despite similar BMI and waist circumference as whites. BMI and waist circumference were weaker estimates of VAT in Filipino and African-American women than in whites. Type 2 diabetes prevalence was highest among Filipino women at every level of VAT, but VAT did not explain their elevated type 2 diabetes risk.     

Development of a culturally relevant body image instrument among urban African Americans

OBJECTIVE: To validate a culturally relevant body image instrument among urban African Americans through three distinct studies. RESEARCH METHODS AND PROCEDURES: In Study 1, 38 medical practitioners performed content validity tests on the instrument. In Study 2, three research staff rated the body image of 283 African-American public housing residents (75% women, mean age = 44 years), with the residents completing body image, BMI, and percentage body fat measures. In Study 3, 35 African Americans (57% men, mean age = 42) completed body image measures and evaluated their cultural relevance. RESULTS: In Study 1, 97% to 100% of practitioners sorted the jumbled figures into the correct ascending order. The correlation between the body image figures and the practitioners' weight classifications of the figures was high (r = 0.91). In Study 2, observers arrived at similar ratings of body size with excellent consistency (alpha = 0.95). Ratings of body image were strongly correlated with participant BMI (r = 0.89 to 0.93 across observers and 0.81 for all participants) and percentage of body fat (r = 0.77 to 0.89 across observers and 0.76 for all participants). In Study 3, body image ratings with the new scale were positively correlated with other validated figural scales. The majority of participants reported that figures in the new body image scale looked most like themselves and other African Americans and were easiest to identify themselves with. DISCUSSION: The instrument displayed strong psychometric performance and cultural relevance, suggesting that the scale is a promising tool for examining body image and obesity among African Americans.     

Obesity-related comorbidities in obese African Americans in an outpatient weight loss program

OBJECTIVE: To identify, among obese African-American enrollees in an outpatient weight loss program, differences between those with and without obesity-related comorbidities (ORCMs). RESEARCH METHODS AND PROCEDURES: Data were from 237 obese African Americans (BMI, 30 to 50 kg/m2; 90% women) who enrolled in a 10-week lifestyle weight loss program. Analyses compared subgroups defined by ORCM status (from medical history) on baseline characteristics, program attendance, and postprogram weight change. RESULTS: Most participants (76%) had one or more ORCMs. Those with versus without ORCMs, respectively, were older (mean age, 45.6 vs. 37.1 years; p < 0.001), were less educated (59.2% vs. 76.6% with > 12 years; p = 0.031), were more likely to perceive a physical limitation affecting activity (22.2% vs. 1.8%; p < 0.001), and had higher waist circumference (mean, 113.7 vs. 106.9 cm; p < 0.001) but not BMI (38.3 vs. 37.0 kg/m2; p = 0.095). Logistic regression analyses confirmed the independence of these associations. Having ORCMs was not associated with class attendance or return for data collection after the 10-week program. Postprogram weight change (n = 134) was unrelated to ORCMs, but better weight loss was seen among those without perceived physical limitations (1.9 vs. 0.4 kg in those without versus with limitations; p = 0.069). Conclusion: Data from this clinical sample of obese African Americans suggest that waist circumference is relevant to ORCM status at BMI levels up to 50 kg/m2. Clear indications for tailoring of treatment based on ORCM status were not identified, although the possible influence of ORCM-related activity limitations warrants further study.     

Limits of body mass index to detect obesity and predict body composition

Body mass index (BMI) is commonly used to identify obesity. In this study, we determined how accurately BMI could determine body composition and identify obese from non-obese individuals. Fat-free mass and body fat were determined with bioelectrical impedance. Adiposity was calculated as body fat per body mass and as body fat divided by body height (m2). Obesity was defined as a BMI of at least 30 kg/m2 or an amount of body fat of at least 25% of total body mass for men and at least 30% for women. Obesity as defined by percentage of body fat was always present with a BMI of at least 30 kg/m2. However, 30% of men and 46% of women with a BMI below 30 kg/m2 had obesity levels of body fat. The greatest variability in the prediction of percentage of body fat and body fat divided by height (m2) from regression equations using BMI was at a BMI below 30 kg/m2. In conclusion, using impedance-derived body-fat mass as the criterion, people with BMI of at least 30 kg/m2 are obese. However, significant numbers of people with a BMI below 30 kg/m2 are also obese and thus misclassified by BMI. Percent of body fat and body fat divided by height (m2) are predictable from BMI, but the accuracy of the prediction is lowest when the BMI is below 30 kg/m2. Therefore, measurement of body fat is a more appropriate way to assess obesity in people with a BMI below 30 kg/m2.     

BMI and cervical cancer screening among white, African-American, and Hispanic women in the United States

OBJECTIVES: We examined cervical cancer screening by BMI in white, African-American, and Hispanic women and explored women's reasons for not undergoing screening. RESEARCH METHODS AND PROCEDURES: We used logistic regression to examine Pap testing in the preceding 3 years across BMI groups for white (n = 6419), African-American (n = 1715), and Hispanic women (n = 1859) age 18 to 75 years who responded to the 2000 National Health Interview Survey. We used bivariable analyses to describe women's reasons for not undergoing testing and examined whether unscreened women received physician recommendations for screening. RESULTS: Of 12,170 women, 50% were normal weight, 26% were overweight, and 21% were obese. The proportion who reported Pap testing in the last 3 years was 86% in whites, 88% in African Americans, and 78% in Hispanics. After adjustment for sociodemographics, health care access, and illness burden, severely obese white women (BMI = 40+ kg/m2) were significantly less likely to undergo Pap testing (relative risk, 0.92; 95% CI, 0.83 to 0.99) compared with normal weight women. BMI was not associated with screening in African Americans or Hispanics. A higher proportion of obese white women than normal weight women cited putting off the test or embarrassment or discomfort as the primary reason for not undergoing screening. Among the unscreened, obese women were as likely as normal weight women to receive a physician recommendation to undergo screening. DISCUSSION: Disparities in cervical cancer screening by body weight persist for white women with severe obesity. Disparities were not explained by differences in the rate of physician recommendations for screening, but obese white women may be more likely to delay screening or to find screening painful, uncomfortable, or embarrassing than normal weight white women. Efforts to increase screening among obese women should address women's reservations about screening.     

Changes in body mass index and its relationships to other cardiovascular risk factors among Japanese population: results from the 1980 and 1990 national cardiovascular surveys in Japan.

Few studies have attempted to investigate the changes in body mass index (BMI) and its relationship to other cardiovascular factors in Asian populations, including Japanese. Data from two national cross-sectional surveys on circulatory disorders in 1980 and 1990 in Japan were used in this study. The sample consisted of 10,556 participants in the 1980 survey and 8,385 in the 1990 survey, aged > or = 30 years. The results show that after adjusting for age, smoking, alcohol consumption (ALC) and daily life physical activity (PA), mean BMI increased 0.49 kg/m2 (95% confidence interval: 0.34-0.65) in men aged 30-59 and 0.61 kg/m2 (0.37-0.86) in those aged > or = 60 from 1980 to 1990. In women, however, mean BMI decreased 0.24 kg/m2 (-0.39 0.09) in those aged 30-59 and increased 0.38 kg/m2 (0.12-0.64) in those aged > or = 60. BMI was significantly associated with hypertension, diabetes and hypercholesterolaemia. In both genders, cu-smokers had lower mean BMI than never smokers, while among the cu-smokers, mean BMI was positively associated with the number of cigarettes smoked per day. In men, BMI was positively associated with ALC and negatively associated with PA, while in women, BMI was negatively associated with ALC and positively associated with PA. The results suggest that BMI has significantly increased in men and in elderly women. BMI, even in the Japanese population who are characterized by relative low BMI, is significantly associated with several cardiovascular risk factors.     

Obesity and associated coronary heart disease risk factors in a population of low-income African-American and white women: the North Carolina WISEWOMAN project

BACKGROUND: Obesity has been associated with many co-occurring coronary heart disease (CHD) risk factors as well as CHD mortality. These associations have been shown to vary between African-American and white sample populations. METHODS: The authors examined whether obesity co-occurs with several CHD risk factors (diabetes, hypertension, hypercholesterolemia, low high-density lipoprotein cholesterol (HDL-C)), and estimated the 10-year risk for CHD in the North Carolina WISEWOMAN (Well Integrated Screening and Evaluation for Women Across the Nation) study sample. This sample includes low-income African-American and white women (> or = 50 years of age). RESULTS: Among white women (n = 1,284), 34% were overweight (BMI = 25.0-29.99 kg/m(2)) and 35% obese (BMI > or = 30 kg/m(2)); among African-American women (n = 754), 28% were overweight and 59% obese. Among obese and nonobese African-American women, the prevalence of three or more co-occurring risk factors was similar (obese = 17.7% (95% confidence interval (CI): 13.9, 21.6) and nonobese = 13.3% (95% CI: 8.7, 17.8)). By contrast, the prevalence among white women was greater among the obese (26.9% (95% CI: 22.9, 31.0)) than the nonobese (13.0% (95% CI: 9.7, 16.2)). CONCLUSIONS: The differences between and within African-American and white women may be accounted for by the high levels of HDL-C among obese and nonobese African-American women.     

Is percentage body fat differentially related to body mass index in Hispanic Americans,African Americans,and European Americans?

BACKGROUND: Limited research has been done to explore differences between ethnic groups, including Hispanic Americans (HAs), in the association between percentage body fat (PBF) and body mass index (BMI; in kg/m(2)); the numbers of HAs are increasing in the US population. OBJECTIVE: We investigated whether the relation between PBF and BMI in adult HAs differed from that of African Americans (AAs) and European Americans (EAs). DESIGN: We used a multiple regression model in which PBF measured with dual energy X-ray absorptiometry was predicted by the reciprocal of BMI (1/BMI; in m(2)/kg) in a sample of 487 men (n(EA) = 192, n(AA) = 148, and n(HA) = 147) and 933 women (n(EA) = 448, n(AA) = 304, and n(HA) = 181). RESULTS: For men, our results showed no significant differences between HAs and EAs, AAs and EAs, or HAs and AAs in the slope of the line relating 1/BMI to PBF. In women, there were significant differences in PBF as predicted by BMI between HAs and EAs (P < 0.002) and AAs and HAs (P = 0.020), but not between AAs and EAs. When PBF was estimated on the basis of predicting equations, the trend of the predicted PBF value in women differed according to ethnic group and BMI category. At a BMI < 30, HAs tended to have more body fat than did EAs and AAs, and at a BMI > 35, EAs tended to have more body fat than did the other groups. CONCLUSIONS: Our results show that the relation between PBF and BMI in HA women differs from that of EA and AA women.     

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

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

Serum iron and body fat distribution in a multiethnic cohort of adults living in New York City

OBJECTIVE: To examine the relationship between serum iron and body composition in a multiracial adult cohort. METHODS: The analysis consisted of 670 participants on whom blood analysis and anthropometric data were available. The participants were recruited as part of the Rosetta Study (1990-2000), which was designed to assess body composition in a multiethnic cohort of healthy adults. Fasting iron level was measured as part of a biochemistry panel. Dual x-ray absorptiometry was used to assess fat mass. Anthropometric measures included waist circumference and body mass index (BMI; calculated as kg/m(2)) as an index of abdominal adiposity and overall body fatness, respectively. RESULTS: In the study cohort the mean age was 54+/-17 years and 60.9% were overweight or obese (BMI > or =25). Men had higher serum iron levels (94.91+/-34.52 microg/dL [16.99+/-6.18 micromol/L] vs 82.17+/-32.62 microg/dL [14.71+/-5.84 micromol/L]) and larger waist circumference (91.98+/-11.87 cm vs 85.24+/-12.37 cm) compared with women (P<0.001). Iron was inversely correlated with BMI (r=-0.23, P<0.001), waist circumference (r=-0.19, P<0.05), and fat mass (r=-0.19, P<0.05) among Hispanic women but not among African-American, white, or Asian women or in men of any race/ethnic group. CONCLUSIONS: The results of this study show an inverse association of measures of body fat distribution and total fat mass with serum iron level in Hispanic women. Studies designed to explore how micronutrients are used by the body at varying degrees of body fatness could provide useful information on the micronutrient-related comorbidities of obesity.     

Work-related physical activity is not associated with body mass index and obesity

OBJECTIVE: To analyze the association of work-related physical activity (WRPA) and leisure-time physical activity (LTPA) with body mass index (BMI) and obesity in the Spanish adult population aged 20 to 60 years. RESEARCH METHODS AND PROCEDURES: The data were taken from the 1993 Spanish National Health Survey. We analyzed a sample of 12,044 men and women representative of the Spanish population aged 20 to 60 years. BMI and frequency of obesity (BMI > or = 30 kg/m(2)) were obtained from self-reported weight and height. Multiple linear regression and logistic regression models were constructed, adjusting for the main confounding factors. WRPA and LTPA were measured by two questions to classify subjects into four categories of physical activity. RESULTS: Neither mean BMI nor percentage of obesity varied significantly (p > 0.05) by WRPA. Mean BMI was significantly higher (p < 0.01) in those who were inactive in their leisure time (25.90 kg/m(2) in men and 24.43 kg/m(2) in women) than in those who reported vigorous activity (24.42 kg/m(2) and 22.97 kg/m(2) in men and women, respectively). The odds ration (OR) for obesity decreased with increasing level of LTPA in both men (OR of 0.64 for vigorous activity) and women (OR = 0.68), showing a statistically significant dose-response relation in both men (for linear trend, p = 0.0021) and women (p = 0.0245). DISCUSSION: These results raise questions about the association between WRPA and obesity and suggest the need to reexamine models of the obesity epidemic that point to automation of the workplace as one of the major explanatory factors.     

Relation of adiposity and body fat distribution to body mass index in Australians of Aboriginal and European ancestry

OBJECTIVE: To compare the relations of adiposity and body fat distribution to body mass index (BMI) in Australians of Aboriginal and European ancestry. DESIGN: Cross-sectional volunteer samples. SETTING: Australian Aboriginal communities in remote central and northern Australia, urban European Australians resident in Melbourne, Australia. SUBJECTS: Healthy Aboriginal (130 women, 120 men) and European Australians (100 women, 47 men) with a BMI<30 kg/m(2), aged 18-35 y; all women were nonpregnant. INTERVENTIONS: Anthropometric variables and resistance-using a four-terminal impedance plethysmograph-were measured. RESULTS: Aboriginal women and men were significantly shorter and weighed less than European Australians (P<0.05). Aboriginal women had a significantly larger waist circumference and waist-to-hip ratio (WHR, P<0.0005) compared to European Australian women. The sum of four skinfold thicknesses (SFT) (S4) and trunk SFT was higher in Aboriginals as compared to European Australian women (P<0.0005); however, limb SFT tended to be lower (P=0.06). On the other hand, BMI was significantly lower in Aboriginals compared to European Australian men (P=0.011), as was hip circumference (P=0.001); however, WHR was significantly (P=0.007) higher. On regression analysis, Aboriginal women and men were significantly heavier than European Australians for the same height(2)/resistance (surrogate for fat-free mass) and S4 (surrogate for subcutaneous fat); and that Aboriginal men had a significantly higher BMI (by 1.2 kg/m(2); P<0.0005) for any given S4 and height(2)/resistance values, compared to European Australian men. CONCLUSION: Aboriginal and European Australians have a significantly different body fat distribution and fat mass for a given body weight or BMI. Use of the World Health Organization recommended BMI ranges to determine weight status may be inappropriate in Australian Aboriginal people.     

Social and dietary determinants of body mass index of adult Jamaicans of African origin

OBJECTIVES: To determine the relationships between body mass index (BMI) and diet, social and behavioural factors among adult Jamaicans of African origin. DESIGN: Cross-sectional. SETTING: Urban communities in Jamaica, West Indies. SUBJECTS: Three-hundred and sixty-three males and 561 females of African origin, aged 25-74 y. RESULTS: Women had higher mean BMIs (27.5+/-6.4 kg/m(2)) than men (23.4+/-4.3 kg/m(2)); 30.7% of women compared with 6.7% of men were obese. There was a tendency for obese men to have higher percentage of intakes from fat and less from carbohydrate, and women reported diets in which the percentage contribution of protein increased significantly with increasing BMI. In multivariate analyses, BMI was not explained by energy but was associated with protein intakes in females only. Predictors of relative weight were inversely related. Social (marital status) and behavioural (cigarette smoking) factors predicted BMI in both genders; older age in men and increased fibre intakes in women were associated with lower BMI. CONCLUSIONS: Social and behavioural factors are important determinants of body weight. Further investigations are needed which consider factors such as physical activity, genetic and other environmental variables as predictors of relative weight.     

Regional subcutaneous-fat loss induced by caloric restriction in obese women

OBJECTIVE: With anthropometric models using skinfolds and circumferences, we studied changes in the percentage of subcutaneous fat in the total cross-sectional area (SF%) at four body sites in obese women, before and after weight loss induced by 6 months of caloric restriction. RESEARCH METHODS AND PROCEDURES: In 61 obese women [31 African Americans and 30 whites; ages, 24 to 68 years; body mass index (BMI), > or =28 kg/m(2)], we measured SF% at the midpoint of the upper arm and thigh and the waistline and hipline, and we measured the percentage of total body fat by DXA before (Obs#1) and after (Obs#2) a 6-month nonintervention control period and then after 6 months on a 1200 kcal/d diet (Obs#3). RESULTS: The mean body weight and BMI increased (1.8 kg and 0.61 kg/m(2); p = 0.0001), but there were no significant changes in any other body composition measurements from Obs#1 to Obs#2. The means of Obs#3 for weight and BMI decreased by 11%, and the percentage of total body fat decreased by 13% of Obs#2 mean values (p = 0.0001). The mean SF% at each site decreased 7.6% to 18.0% of the Obs#2 mean values (p < 0.001). The SF% decreases were greater at mid-arm and mid-thigh than in the cross-sectional regions at the waistline and hipline (p = 0.05). There was no interaction between age or ethnicity (p > 0.2). CONCLUSIONS: In obese women, caloric restriction alone reduces anthropometrically measured subcutaneous fat proportionally more in peripheral than in central regions.     

Defining obesity by body mass index in the Thai population: an epidemiologic study

The objective of this study was to develop cut-off values and evaluate the accuracy of body mass index (BMI) in the definition of obesity in the Thai population. A cross-sectional, epidemiologic study in 340 men and 507 women aged 50 +/- 16 yr (mean +/- SD; range: 20-84 yr), were sampled by stratified clustering sampling method. Body composition, including percentage body fat (%BF), was measured by dual energy X-ray absorptiometry (GE Lunar Corp, Madison, WI). BMI was obtained by dividing weight (in kg) by height (in m2). The "golden standard "for defining obesity was %BF > or =25% in men and %BF > or =35% in women. The %BF-based prevalence of obesity in men and women was 18.8% and 39.5%, respectively. However, using the BMI cut-off of > or =30, only 2.9% of men and 8.9% of women were classified as obese. In the cubic regression model, BMI was a significant predictor of %BF, such that in men a BMI of 27 kg/m2 would predict a %BF of 25%, and in women a BMI of 25 kg/m2 would correspond to a %BF of 35%. The area under the receiver operating characteristic curve for BMI was approximately 0.87 (95% CI: 0.82-0.92) and 0.86 (95% CI: 0.83-0.90) in men and women, respectively. In conclusion, for the Thai population, BMI is a reasonably useful indicator of obesity; however, the cut-off values of BMI for diagnosing obesity should be lowered to 27 kg/m2 in men and 25 kg/m2 in women.     

Dietary medium-chain triacylglycerols suppress accumulation of body fat in a double-blind, controlled trial in healthy men and women.

We investigated the effect of long-term ingestion of dietary medium-chain triacylglycerols (MCT) on body weight and fat in humans. Using a double-blind, controlled protocol, we assessed the potential health benefits of MCT compared with long-chain triacylglycerols (LCT) in 78 healthy men and women [body mass index (BMI) > or = 23 kg/m(2): n = 26 (MCT), n = 30 (LCT); BMI < 23 kg/m(2): n = 15 (MCT), n = 7 (LCT)]. Changes in anthropometric variables, body weight and body fat during the 12-wk MCT treatment period were compared with those in subjects consuming the LCT diet. The subjects were asked to consume 9218 kJ/d and 60 g/d of total fat. The energy, fat, protein and carbohydrate intakes did not differ significantly between the groups. Body weight and body fat in both groups had decreased by wk 4, 8 and 12 of the study. However, in the subjects with BMI > or = 23 kg/m(2), the extent of the decrease in body weight was significantly greater in the MCT group than in the LCT group. In subjects with BMI > or = 23 kg/m(2), the loss of body fat in the MCT group (-3.86 +/- 0.3 kg) was significantly greater than that in the LCT group (-2.75 +/- 0.2 kg) at 8 wk. In addition, in subjects with BMI > or = 23 kg/m(2), the decrease in the area of subcutaneous fat in the MCT group was significantly greater than that in the LCT group at wk 4, 8 and 12. These results suggest that the MCT diet may reduce body weight and fat in individuals (BMI > or = 23 kg/m(2)) more than the LCT diet.     

孕前人体质量指数与妊娠高血压综合征的关系

目的 了解孕前人体质量指数(body mass index,BMI)与妊娠高血压综合征(pregnancy-induced hypertension,PIH)发生危险性之间的关系.方法 数据来自"中美预防出生缺陷和残疾合作项目"中嘉兴地区的围产保健监测数据库.研究对象为1995-2000年在嘉兴地区参加婚前或孕前体检且分娩了单胎活产儿的孕满20周的83 159名孕产妇.运用X2检验或X<,趋势>2检验比较不同BMI组或其他特征人群PIH发病率的差别,利用多元logistic回归分析孕前BMI与PIH发生危险性之间的关系.结果 PIH发病率为11.01%(9153/83 159;95%CI:10.79%～11.22%).PIH的发病率自BMI<18.5 kg/m2组的9.08%(1405/15 472;95%CI:8.63%～9.54%),18.5～22.9 kg/m2组的10.82%(6389/59 054;95%CI:10.57%～11.07%),23.0～24.9 kg/m2组的14.63%(943/6444;95%CI:13.78%～15.52%)升至BMI≥25/0 kg/m2组的19.00%(416/2189;95%CI:17.38%～20.71%),差异有统计学意义(X<,趋势>2=261.028,P=0.000).以BMI为18.5～22.9 kg/m2者为参照组,BMI<18.5 kg/m2、23.0～24.9 kg/m2和≥25.0 kg/m2组发生PIH的RR值分别为0.82(95%CI:0.77～0.87)、1.41(95%CI:1.31～1.52)和1.93(95%CI:1.73～2.16).调整地区、年龄、文化程度、职业、产次、产前检查次数和既往高血压病史或家族史后,上述RR值分别为0.85(95%CI:0.80～0.90)、1.37(95%CI:1.27～1.47)和1.88(95%CI:1.68～2.10).结论 PIH的发生危险随孕前BMI的升高而升高.     

Weight gain continues in the 1990s: 10-year trends in weight and overweight from the CARDIA study. Coronary Artery Risk Development in Young Adults

The prevalence of obesity increased in the United States through the 1980s. The authors examined 10-year aging and secular (time-related) trends in the Coronary Artery Risk Development in Young Adults (CARDIA) cohort for indications of whether these trends are continuing and for ages of peak weight gain in young adults. CARDIA is a population-based, prospective study of 5,115 African-American and White men and women aged 18-30 years at baseline. Body weight and overweight prevalence were measured at five time points from 1985-1986 to 1995-1996. Linear, mixed-model regression was used to partition weight gain into that due to secular trends and that due to aging. Prevalence of overweight (body mass index (BMI) > or = 25.0 kg/m2) increased markedly, and prevalence of severe obesity (BMI > or = 40.0 kg/m2) doubled in all race-sex groups. Each race-sex group experienced significant secular weight gains, ranging from 0.96 kg/year (95% confidence interval: 79, 1.13) in African-American women to 0.55 kg/year (95% confidence interval: 0.41, 0.69) in White women. Significant secular gains were present during each follow-up period. Each race-sex group also experienced significant weight increases related to aging during their early to midtwenties. Secular trends for weight gain are continuing in CARDIA, but the magnitude of weight gain differed among the four race-sex groups.