Baseline Between Body Mass Index Research Articles

Esophageal cancer and body mass index: Results from a prospective study of 220,000 men in China and a meta‐analysis of published studies

Several epidemiological studies have reported on the association between body mass index (BMI) and risk of esophageal cancer, but these were mostly in Western populations where many are overweight or obese. There is little direct evidence about the relationship in China where the mean BMI is relatively low and the disease rate is high. We examined the data from a population-based prospective study of 220,000 Chinese men aged 40-79 without a previous history of cancer (mean BMI 21.7 kg/m(2)), which included 1,082 esophageal cancer deaths during 10 years of follow-up. Adjusted hazard ratios for death from esophageal cancer by baseline BMI category were calculated using Cox proportional hazards models. Even among men with good self-assessed health and BMI >or= 18.5 kg/m(2), there was a strong inverse association between BMI and death from esophageal cancer, with each 5 kg/m(2) higher BMI associated with 25% (95%CI: 11-36%) lower esophageal cancer mortality. This inverse association persisted when analysis was restricted to men who had never smoked or when the first 5 years of follow-up were excluded. The strength of the relationship was consistent with the pooled estimate for squamous cell carcinoma of the esophagus in a meta-analysis of prospective studies (31% lower relative risk per 5 kg/m(2) higher BMI; 95% CI: 25-37%), but contrasted with that for adenocarcinoma which showed a positive association with BMI. Together, these data provide reliable evidence that in many populations low BMI is associated with an increased risk of squamous cell carcinoma of the esophagus.

Unintentional Weight Loss Predicts Decline in Activities of Daily Living Function and Life-Space Mobility Over 4 Years Among Community-Dwelling Older Adults

The relationship between body mass index (BMI), weight loss, and changes in activities of daily living (ADL) function and mobility in older adults is not clear. We sought to study the relationship between BMI and weight loss on the rate of decline in ADL function and life-space mobility over a 4-year period among older African Americans and whites. The participants were 983 enrollees in the University of Alabama at Birmingham (UAB) Study of Aging, a longitudinal study of mobility among community-dwelling older adults stratified to achieve a balanced sample in terms of sex, race, and residence. Primary outcome measures were changes in ADL function and mobility assessed by the UAB Study of Aging Life-Space Assessment (LSA) which were measured every 6 months. Relative to normal weight participants, those with BMI levels in the obese range did not show more rapid ADL functional decline, but a history of unintentional weight loss predicted more rapid decline. Relative to normal-weight participants, other BMI categories were not associated with more rapid decline in LSA scores. However, unintentional weight loss predicted more rapid declines in LSA. Intentional weight loss had no relation to ADL function or LSA decline. In this population of community-dwelling older African Americans and whites, neither BMI nor intentional weight loss had an association with rate of functional decline. Unintentional weight loss had a negative relation with rate of functional decline, regardless of baseline BMI. Whether this is causal remains to be determined.

Body mass index and mortality in men: evaluating the shape of the association

Controversy regarding the relationship between body mass index (BMI) and mortality continues to exist. Most of the previous studies have not comprehensively accounted for major sources of bias. We examined the association between BMI and all-cause mortality according to pre-existing disease and smoking status in a large prospective cohort. Participants were 99 253 male physicians in the Physicians' Health Study enrollment cohort (40-84 years) who provided self-reported information in 1982. We used Cox proportional hazards regression to examine the association between baseline BMI and mortality. A total of 5438 men died (median follow-up, 5.7 years). Although a U-shaped association between BMI and all-cause mortality was seen among all men, we found a linear relationship when accounting for potential sources of bias. In the optimal model excluding men who died within 2 years, and adjusting for age, smoking, alcohol consumption, physical activity, prior disease and interactions between BMI and prior disease, and between BMI and smoking, those with BMI <20.0 kg/m(2) had a relative risk (RR) of death of 0.88 (95% confidence interval (CI), 0.56-1.40), as compared to men with BMI 22.5-24.9 kg/m(2). By contrast, men with BMI 30.0-34.9 kg/m(2) had an RR of 1.45 (95% CI, 1.10-1.91) and those with BMI >or=35.0 kg/m(2) had an RR of 1.62 (95% CI, 1.12-2.35; P for linear trend, <0.001). According to WHO categories, men in the 'overweight' range (BMI 25.0-29.9 kg/m(2)) had an RR of 1.20 (95% CI, 1.05-1.38) as compared to men in the 'normal' range (BMI <25.0 kg/m(2)). In this large, prospective cohort, we found a consistent linear association between higher BMI and increased risk of mortality after accounting for several potential sources of bias, even among those within the 'overweight' range of BMI. Public health messages should emphasize the preponderance of evidence supporting the adverse health effects associated with higher body weight.

Prospective study of body mass index, height, physical activity and incidence of bladder cancer in US men and women

We evaluated prospectively the association between body mass index (BMI), height, recreational physical activity and the risk of bladder cancer among US adults. Data were used from 2 ongoing cohorts, the Health Professionals Follow-up Study and the Nurses' Health Study, with 3,542,012 years of follow-up and 866 incident bladder cancer cases (men = 507; women = 359) for the anthropometric analysis and 1,890,476 years of follow-up and 706 incident bladder cancer cases (men = 502; women = 204) for the physical activity analysis. Cox proportional hazard models were used to estimate incidence rate ratios (RR) and 95% confidence intervals (CI) between BMI, height, physical activity and bladder cancer risk adjusting for age, pack-years of cigarette smoking and current smoking. Estimates from each cohort were pooled using a random-effects model. We observed no association between baseline BMI and bladder cancer risk, even when we compared a BMI of > or =30 kg/m(2) to a BMI of 18-22.9 kg/m(2) [pooled multivariate (MV) RR, 1.16; 95% CI: 0.89-1.52]. A weak, but statistically significant, association was observed for the same comparison after excluding bladder cancer cases diagnosed within the first 4 years of follow-up (pooled MV RR, 1.33; 95% CI: 1.01-1.76). Height was not related to bladder cancer risk (pooled MV RR, 0.82; 95% CI: 0.65-1.03, top vs. bottom quintile). Total recreational physical activity also was not associated with the risk of bladder cancer (pooled MV RR, 0.97; 95% CI: 0.77-1.24, top vs. bottom quintile). Our findings do not support a role for BMI, height or physical activity in bladder carcinogenesis.

Body-Mass Index and Symptoms of Gastroesophageal Reflux in Women

Overweight and obese persons are at increased risk for gastroesophageal reflux disease. An association between body-mass index (BMI)--the weight in kilograms divided by the square of the height in meters - and symptoms of gastroesophageal reflux disease in persons of normal weight has not been demonstrated. In 2000, we used a supplemental questionnaire to determine the frequency, severity, and duration of symptoms of gastroesophageal reflux disease among randomly selected participants in the Nurses' Health Study. After categorizing women according to BMI as measured in 1998, we used logistic-regression models to study the association between BMI and symptoms of gastroesophageal reflux disease. Of 10,545 women who completed the questionnaire (response rate, 86 percent), 2310 (22 percent) reported having symptoms at least once a week, and 3419 (55 percent of those who had any symptoms) described their symptoms as moderate in severity. We observed a dose-dependent relationship between increasing BMI and frequent reflux symptoms (multivariate P for trend <0.001). As compared with women who had a BMI of 20.0 to 22.4, the multivariate odds ratios for frequent symptoms were 0.67 (95 percent confidence interval, 0.48 to 0.93) for a BMI of less than 20.0, 1.38 (95 percent confidence interval, 1.13 to 1.67) for a BMI of 22.5 to 24.9, 2.20 (95 percent confidence interval, 1.81 to 2.66) for a BMI of 25.0 to 27.4, 2.43 (95 percent confidence interval, 1.96 to 3.01) for a BMI of 27.5 to 29.9, 2.92 (95 percent confidence interval, 2.35 to 3.62) for a BMI of 30.0 to 34.9, and 2.93 (95 percent confidence interval, 2.24 to 3.85) for a BMI of 35.0 or more. Even in women with a normal baseline BMI, an increase in BMI of more than 3.5, as compared with no weight changes, was associated with an increased risk of frequent symptoms of reflux (odds ratio, 2.80; 95 percent confidence interval, 1.63 to 4.82). BMI is associated with symptoms of gastroesophageal reflux disease in both normal-weight and overweight women. Even moderate weight gain among persons of normal weight may cause or exacerbate symptoms of reflux.

Association Between Body Mass Index and CKD in Apparently Healthy Men

Overweight and obesity are well-established risk factors for cardiovascular disease and decline in kidney function in individuals with existing chronic kidney disease (CKD). Conversely, their association with the development of CKD is less clear. We evaluated the association between body mass index (BMI) and risk for CKD in a cohort of 11,104 initially healthy men who participated in the Physicians' Health Study and provided a blood sample after 14 years. BMI was calculated from self-reported weight and height. We estimated glomerular filtration rate (GFR) by using the abbreviated equation from the Modification of Diet in Renal Disease Study and defined CKD as GFR less than 60 mL/min/1.73 m2 (<1 mL/s/1.73 m2). After an average 14-year follow-up, 1,377 participants (12.4%) had a GFR less than 60 mL/min/1.73 m2 (<1 mL/s/1.73 m2). Higher baseline BMI was associated consistently with increased risk for CKD. Compared with participants in the lowest BMI quintile (<22.7 kg/m2), those in the highest quintile (>26.6 kg/m2) had an odds ratio (OR) of 1.45 (95% confidence interval [CI], 1.19 to 1.76; P trend <0.001) after adjusting for potential confounders. We found similar associations by using different categories of BMI. Compared with men who remained within a +/-5% range of their baseline BMI, those who reported a BMI increase greater than 10% had a significant increase in risk for CKD (OR, 1.27; 95% CI, 1.06 to 1.53). In this large cohort of initially healthy men, BMI was associated significantly with increased risk for CKD after 14 years. Strategies to decrease CKD risk might include prevention of overweight and obesity.

Body mass index and parent-reported self-esteem in elementary school children: evidence for a causal relationship.

To clarify relationships between body mass index (BMI) and self-esteem in young children at a population level. To assess whether low self-esteem precedes or follows development of overweight/obesity in children. Prospective cohort study in elementary schools throughout Victoria, Australia. Child BMI and self-esteem were measured in 1997 and 2000. Random sample of 1,157 children who were in the first 4 y of elementary school (aged 5-10 y) at baseline. BMI was calculated from measured height and weight, then transformed to z-scores. Children were classified as nonoverweight, overweight or obese based on international cut-points. Low child self-esteem was defined as a score below the 15th percentile on the self-esteem subscale of the parent-reported Child Health Questionnaire. Overweight/obese children had lower median self-esteem scores than nonoverweight children at both timepoints, especially at follow-up. After accounting for baseline self-esteem, higher baseline BMI z-score predicted poorer self-esteem at follow-up (P=0.008). After accounting for baseline BMI z-score, poorer baseline self-esteem did not predict higher BMI z-score at follow-up. While nonoverweight children with low baseline self-esteem were more likely to develop overweight/obesity (OR=2.1, 95% CI=1.2, 3.6), this accounted for only a small proportion of the incidence of overweight. Our data show an increasingly strong association between lower self-esteem and higher body mass across the elementary school years. Overweight/obesity precedes low self-esteem in many children, suggesting a causal relationship. This indicates that prevention and management strategies for childhood overweight/obesity need to begin early to minimise the impact on self-esteem.

Change in serum lipids and body mass index by age, sex, and smoking status: The Tromsø study 1986–1995

The steady increase in body weight is becoming a major health problem in western societies. How body weight increase influences established disease risk factors is the focus of our study. We assessed the association between 8-year change in body weight and serum lipids in a population-based study comprising 15,624 men and women aged 20 to 61 years at baseline in 1986. Comparisons between different strata of age, sex, initial weight, and categories of smoking status change were also addressed. Significant associations between body mass index (BMI) change and change in high density lipoprotein (HDL) cholesterol, total cholesterol, and triglycerides were observed in all 10-year age groups both in men and women. The weakest associations were observed in persons older than 50 years of age and the associations were also weaker in women than in men. In quartile groups of baseline BMI, a significant linear trend was observed for HDL cholesterol in men and for total cholesterol in both men and women. The associations were less adverse for persons in a higher quartile group of baseline BMI. The association between BMI change and serum lipid change was strongest for persons who were consistent smokers or non-smokers at each survey. We conclude that an increase in BMI has been shown to be associated with adverse changes in serum lipids. The associations were weaker in women than in men.

Body mass index in adolescence in relation to total mortality: 32-year follow-up of 227,000 Norwegian boys and girls.

A large number of studies have explored the relation between body mass index (BMI) and mortality in adults. The relation between BMI in adolescence and mortality has been investigated to a lesser extent. It has been suggested that all-cause mortality is elevated among those who were overweight during adolescence, but the limitation of previous studies has been study size. The present study explored this relation in a Norwegian cohort of 227,003 boys and girls, aged 14-19 years, whose height and weight were measured during tuberculosis screening in 1963-1975. These persons were followed for an average of 31.5 years (about 7.2 million person-years). A total of 7,516 deaths were registered. Multivariate Cox proportional hazards regression models were used in the analyses. An increasing risk of death by increasing BMI in adolescence was observed. Mortality among males whose baseline BMI was between the 85th and 95th percentiles and above the 95th percentile in the US reference population was 30% and 80% higher, respectively, than that among those whose baseline BMI was between the 25th and 75th percentiles. The corresponding rates among females were 30% and 100%. The excess mortality among adolescents whose BMI was high was not clearly manifested before they reached their thirties. Hence, BMI in adolescence is predictive of adult mortality.