Clinical Utility of Waist Circumference in Predicting All‐cause Mortality in a Preventive Cardiology Clinic Population: A PreCIS Database Study

Although obesity is a risk factor for mortality, it is unclear whether waist circumference (WC) is a better predictor of mortality than BMI in a clinical setting of patients at high risk for coronary artery disease (CAD). Thus, we compared the association between WC and BMI with all‐cause mortality in relation to traditional CAD risk factors in a high‐risk cohort. Study population included 5,453 consecutive new patients seen between 1996 and 2005 for management of CAD risk factors in a preventive cardiology clinic. Mortality was determined from the Social Security Death Index. There were 359 deaths over a median follow‐up of 5.2 years. Mortality was greater in high (>102 cm in men and >88 cm in women) vs. normal WC in both genders (P < 0.01). The unadjusted Cox proportional hazard ratio (HR) for continuous WC (per cm) was 1.02 (P < 0.001) in both genders and remained significant after adjustment for CAD risk factors (HR = 1.01 in men, HR = 1.03 in women, both P < 0.05). BMI did not associate statistically with mortality. WC associated with diabetes mellitus (DM) and CAD prevalence (P < 0.001). BMI associated only with DM (P < 0.001) and this association disappeared when WC was added to the model. We conclude that WC is an independent predictor of all‐cause mortality in a preventive cardiology population. These data affirm the clinical importance of WC measurements for mortality, DM, and CAD risk prediction and suggest that obesity‐specific interventions targeting WC in addition to traditional risk factor management may favorably impact these outcomes.     

The Relation of Body Mass Index,Cardiorespiratory Fitness,and All‐Cause Mortality in Women

Objective: To examine the relation of body mass index (BMI), cardiorespiratory fitness (CRF), and all‐cause mortality in women. Research Methods and Procedures: A cohort of women (42.9 ± 10.4 years) was assessed for CRF, height, and weight. Participants were divided into three BMI categories (normal, overweight, and obese) and three CRF categories (low, moderate, and high). After adjustment for age, smoking, and baseline health status, the relative risk (RR) of all‐cause mortality was determined for each group. Further multivariate analyses were performed to examine the contribution of each predictor (e.g., age, BMI, CRF, smoking status, and baseline health status) on all‐cause mortality while controlling for all other predictors. Results: During follow‐up (113,145 woman‐years), 195 deaths from all causes occurred. Compared with normal weight (RR = 1.0), overweight (RR = 0.92) and obesity (RR = 1.58) did not significantly increase all‐cause mortality risk. Compared with low CRF (RR = 1.0), moderate (RR = 0.48) and high (RR = 0.57) CRF were associated significantly with lower mortality risk (p = 0.002). In multivariate analyses, moderate (RR = 0.49) and high (RR = 0.57) CRF were strongly associated with decreased mortality relative to low CRF (p = 0.003). Compared with normal weight (RR = 1.0), overweight (RR = 0.84) and obesity (RR = 1.21) were not significantly associated with all‐cause mortality. Discussion: Low CRF in women was an important predictor of all‐cause mortality. BMI, as a predictor of all‐cause mortality risk in women, may be misleading unless CRF is also considered.     

Disability,Arthritis, and Body Weight among Adults 45 Years and Older

Objectives : To examine the association between body weight and disability among persons with and without self‐reported arthritis. Research Methods and Procedures : Data were analyzed for noninstitutionalized adults, 45 years or older, in states that participated in the Behavioral Risk Factor Surveillance System. Self‐reported BMI (kilograms per meter squared) was used to categorize participants into six BMI‐defined groups: underweight (<18.5), normal weight (18.5 to <25), overweight (25 to <30), obese, class 1 (30 to <35), obese, class 2 (35 to <40), and obese, class 3 (≥40). Results : Class 3 obesity (BMI ≥ 40) was significantly associated with disability among participants both with and without self‐reported arthritis. The adjusted odds ratio (AOR) for disability in participants with class 3 obesity was 2.75 [95% confidence interval (CI) = 2.22 to 3.40] among those with self‐reported arthritis and 1.77 (95% CI = 1.20 to 2.62) among those without self‐reported arthritis compared with those of normal weight (BMI 18.5 to <25). Persons with self‐reported arthritis who were obese, class 2 (BMI 35 to <40) and obese, class 1 (BMI 30 to <35) and women with self‐reported arthritis who were overweight (BMI 25 to <30) also had higher odds of disability compared with those of normal weight [AOR = 1.72 (95% CI = 1.47 to 2.00), AOR = 1.30 (95% CI = 1.17 to 1.44), and AOR = 1.18 (95% CI = 1.06 to 1.32), respectively]. Discussion : Our findings reveal that obesity is associated with disability. Preventing and controlling obesity may improve the quality of life for persons with and without self‐reported arthritis.     

Obesity and Medicare Expenditure: Accounting for Age‐Related Height Loss

To determine the relationship between BMI and Medicare expenditure for adults 65‐years and older and determine whether this relationship changes after accounting for misclassification due to age‐related height loss. Using a cross sectional study design, the relationship between BMI and fee‐for‐service Medicare expenditure was examined among beneficiaries who completed the Medicare Current Beneficiary Survey (MCBS) in 2002, were not enrolled in Medicare Health Maintenance Organization, had a self‐reported height and weight, and were 65 and older (n = 7,706). Subjects were classified as underweight, normal weight, overweight, obese (obese I), and severely obese (obese II/III). To adjust BMI for the artifactual increase associated with age‐related height loss, the reported height was transformed by adding the sex‐specific age‐associated height loss to the reported height in MCBS. The main outcome variable was total Medicare expenditure. There was a significant U‐shaped pattern between unadjusted BMI and Medicare expenditure: underweight $4,581 (P < 0.0003), normal weight $3,744 (P < 0.0000), overweight $3,115 (reference), obese I $3,686 (P < 0.0039), and obese II/III $4,386 (P < 0.0000). This pattern persisted after accounting for height loss: underweight $4,640 (P < 0.0000), normal weight $3,451 (P < 0.0507), overweight $3,165 (reference), obese I $3,915 (P < 0.0010), and obese II/III $4,385 (P < 0.0004) compared to overweight. In older adults, minimal cost is not found at “normal” BMI, but rather in overweight subjects with higher spending in the obese and underweight categories. Adjusting for loss‐of‐height with aging had little affect on cost estimates.     

Eleven‐year Prevalence Trends of Obesity in Greek Children: First Evidence that Prevalence of Obesity Is Leveling Off

We examined 11‐year (1997–2007) trends in underweight, overweight, and obesity in Greek children. Population data derived from a yearly, school‐based health survey carried out between 1997 and 2007 in >80% of all Greek schools. Height and weight measurements from 651,582 children, aged 8–9 years (boys: 51.2%) were analyzed. The gender‐ and age‐specific BMI cutoff points by the International Obesity Task Force (IOTF) were used in order to define underweight, normal weight, overweight, and obesity. Trend analysis showed an increase in the prevalence of obesity from 7.2 ± 0.2% in 1997 to 11.3 ± 0.2% in 2004 for girls (P < 0.001) and from 8.1 ± 0.2% in 1997 to 12.3 ± 0.2% in 2004 for boys (P < 0.001). An apparent leveling off in obesity rates was observed during 2004–2007 for both boys and girls. The prevalence of overweight rose between 1997 and 2007 from 20.2 ± 0.2% to 26.7 ± 0.2% for girls (P < 0.001) and from 19.6 ± 0.2% to 26.5 ± 0.2% for boys (P < 0.001). The overall prevalence of thinness in the same period remained constant in both sexes. The presented population‐based data revealed that the prevalence of overweight and obesity among 8‐ to 9‐year‐old Greek children is alarmingly elevated, with the overweight rates rising continuously. However, an apparent leveling off in obesity rates for the past 4 consecutive years was documented for the first time in both genders.     

Paradoxical protective effect of central obesity in patients with suspected stable coronary artery disease

Objective:

Increased body mass index (BMI) has been paradoxically inversely associated with the presence of angiographic coronary artery disease (CAD). Central obesity measures, considered to be more appropriate for assessing obesity‐related cardiovascular risk, have been little studied in relation to the presence of CAD. The aim was to investigate the association of central obesity with the presence of angiographic CAD as well as the prognostic significance of obesity measures in CAD prediction when added to other cardiovascular risk factors.

Design and Methods:

Patients with suspected stable CAD (n = 403, age 61 ± 10 years, 302 males) referred for diagnostic coronary angiography with documented anthropometric data were enrolled.

Results:

Significant angiographic CAD was found in 51% of patients. Both BMI (OR = 0.64 per 1 SD increase, P = 0.001) and waist circumference (WC) (OR = 0.54 per 1 SD increase, P < 0.001) were inversely associated with the presence of CAD even after adjustment for cardiovascular risk factors. In subgroup analysis, BMI and WC were significantly inversely associated with the presence of CAD in males, non diabetics, patients >60 years old and patients with Framingham risk score (FRS) >20% (P < 0.01 for all). The addition of BMI or WC in FRS‐based regression models improved prediction of CAD (P = 0.03 and P < 0.001 for BMI and WC respectively) without a significant difference between the two models (P = 0.08).

Conclusions:

Central and overall obesity were independently associated with a reduced prevalence of angiographic CAD, lending further credence to the existence of the ‘obesity paradox’. Obesity measures may further improve risk discrimination for the presence of CAD when added in an established risk score such as FRS.     

Eating Frequency is Associated With Energy Intake but Not Obesity in Midlife Women

Midlife women tend to gain weight with age, thus increasing risk of chronic disease. The purpose of this study was to examine associations between overweight/obesity and behavioral factors, including eating frequency, in a cross‐sectional national sample of midlife women (n = 1,099) (mean age = 49.7 years, and BMI = 27.7 kg/m²). Eating behaviors and food and nutrient intakes were based on a mailed 1‐day food record. BMI was calculated from self‐reported height and weight, and level of physical activity was assessed by self‐reported questionnaire. After exclusion of low‐energy reporters (32% of sample), eating frequency was not associated with overweight/obesity (P > 0.05) and was not different between BMI groups (normal, 5.21 ± 1.79; overweight, 5.16 ± 1.74; obese, 5.12 ± 1.68, P = 0.769). Adjusted logistic regression showed that eating frequency, snacking frequency, breakfast consumption, eating after 10 pm and consuming meals with children or other adults were not significantly associated with overweight/obesity. Total energy intake increased as eating frequency increased in all BMI groups, however, obese women had greater energy intake compared to normal weight women who consumed the same number of meals and snacks. Intake of fruit and vegetables, whole grains, dietary fiber, dairy, and added sugars also increased as eating frequency increased. While eating frequency was not associated with overweight/obesity, it was associated with energy intake. Thus, addressing total energy intake rather than eating frequency may be more appropriate to prevent weight gain among midlife women.     

Eligibility for Obesity Treatment and Risk of Mortality in Men

Objective: To evaluate the risk of all‐cause and cardiovascular disease (CVD) mortality associated with each outcome of the NIH obesity treatment algorithm and to examine the effects of cardiorespiratory fitness on the risk of mortality associated with these outcomes. Research Methods and Procedures: The NIH obesity treatment algorithm was applied to 18, 666 men (20 to 64 years of age) from the Aerobics Center Longitudinal Study in Dallas, TX, examined between 1979 and 1995. Risk of all‐cause and CVD mortality was assessed using Cox proportional hazards regression. Results: A total of 7029 men (37.7%) met the criteria for needing weight loss treatment [overweight (BMI = 25 to 29.9 kg/m² or WC > 102 cm) with ≥2 CVD risk factors or obese (BMI ≥ 30 kg/m²)]. Mortality surveillance through 1996 identified 435 deaths (151 from CVD) during 191, 364 man‐years of follow‐up. Compared with the normal weight reference group, the hazard ratios (95% confidence interval) for death from all causes were 0.63 (0.45 to 0.88), 1.23 (0.98 to 1.54), 1.05 (0.60 to 1.85), and 1.71 (1.64 to 2.31) for men who were overweight with <2 CVD risk factors, overweight with ≥2 CVD risk factors, obese with <2 CVD risk factors, and obese with ≥2 CVD risk factors, respectively. Corresponding hazard ratios for CVD mortality were 0.72 (0.38 to 1.37), 1.67 (1.12 to 2.50), 1.69 (0.67 to 4.30), and 3.31 (2.07 to 5.30). Including physical fitness as a covariate significantly attenuated all risk estimates. Discussion: The NIH obesity treatment algorithm is useful in identifying men at increased risk of premature mortality; however, including an assessment of fitness would help improve risk stratification among all groups of patients.     

Obesity Increases the Risk of Spontaneous Abortion during Infertility Treatment

Objective: This study examines the relationship between body mass and the risk of spontaneous abortion in a large cohort of patients who received infertility treatment. Research Methods and Procedures: This is a retrospective study using data on pregnancies (n = 2349) achieved after treatment in a tertiary medical center from 1987 to 1999. One pregnancy per subject was included, and the subjects were stratified into five body mass groups based on body mass index (BMI): underweight, <18.5 kg/m²; normal, 18.5 to 24.9 kg/m²; overweight, 25 to 29.9 kg/m²; obese, 30 to 34.9 kg/m²; and very obese, ≥35 kg/m². Logistical regression analysis was used. Results: The overall incidence of spontaneous abortion was 20% (476 of 2349). The effect of BMI on the risk of spontaneous abortion was significant after adjusting for several independent risk factors. Compared with the reference group (BMI 18.5 to 24.9 kg/m²), underweight women had a similar risk of spontaneous abortion, whereas there was progressive increase of risk in overweight, obese, and very obese groups (p < 0.05, p < 0.01, and p < 0.001, respectively). Discussion: Of all known risk factors for spontaneous abortion, the control of obesity has great significance because it is noninvasive, potentially modifiable, possibly amenable to low cost, and self‐manageable by patients. This study established a positive relationship between BMI and the risk of spontaneous abortion in women who became pregnant after assisted reproductive technology treatment.     

Obesity,End‐stage Renal Disease,and Survival in an Elderly Cohort With Cardiovascular Disease

Obesity is highly prevalent in African Americans and is associated with increased risk of End‐Stage Renal Disease (ESRD) and death. It is not known if the effect of obesity is similar among blacks and whites. The aim of this study is to examine racial differences in the association of obesity with ESRD and survival in elderly patients (age >65). Data were obtained for 74,167 Medicare patients with acute myocardial infarction (AMI) between February 1994 and July 1995. BMI was calculated as weight (kg) divided by height (m²). We evaluated the association of BMI class with ESRD incidence and death using multivariable Cox proportional hazards models, testing for race‐BMI interactions. Compared to whites, African Americans had higher BMI (26.9 vs. 26.0, P < 0.0001) and estimated glomerular filtration rate (72.4 ml/min/1.73 m² vs. 66.6 ml/min/1.73 m², P < 0.0001). Crude ESRD rates increased with increasing obesity among whites but not among blacks. However, after adjusting for age, sex, and other comorbidities, obesity was not associated with increased ESRD rate among blacks or whites and the interaction between race and BMI was not significant. Furthermore, for both races, patients classified as overweight, class 1 obese, or class 2 obese had similar, significantly better survival abilities compared to normal weight patients and the race BMI interaction was not significant. In conclusion, obesity does not increase risk of ESRD among black or white elderly subjects with cardiovascular disease (CVD). However, both obese blacks and whites, in this population, experience a survival benefit. Further studies need to explore this obesity paradox.     

Body mass index and the risk of head and neck cancer in the Chinese population

ObjectiveTo investigate potential associations between body mass index (BMI) and head and neck cancer (HNC) risk in an East Asian population.MethodsWe conducted a hospital-based multicenter case-control study in East Asia including 921 cases and 806 controls. We estimated the odds ratios (ORs) and 95% confidence intervals (95% CI) for HNC risks by using logistic regression, adjusting on potential confounders.ResultsCompared to normal BMI at interview (18.5–<25 kg/m²), being underweight (BMI < 18.5 kg/m²) was associated with a higher HNC risk (OR = 2.71, 95% CI 1.40–5.26). Additionally, obesity (BMI > 30 kg/m²) was associated with a lower HNC risk (OR = 0.30, 95% CI 0.16–0.57). Being underweight at age 20 was also associated with an increased risk of HNC. However, being underweight at 5 years or 2 years before interview was not associated with a higher risk of HNC.ConclusionWe observed an inverse association between BMI and HNC risk, which is consistent with previous studies in other geographic regions. Being underweight at age 20 was also associated with a higher risk of HNC, suggesting that reverse causality was not the main source of the association.     

Additive Interactions of Maternal Prepregnancy BMI and Breast‐feeding on Childhood Overweight

Objective: To examine the interactions of maternal prepregnancy BMI and breast‐feeding on the risk of overweight among children 2 to 14 years of age. Research Methods and Procedures: The 1996 National Longitudinal Survey of Youth, Child and Young Adult data in the United States were analyzed (n = 2636). The weighted sample represented 51.3% boys, 78.0% whites, 15.0% blacks, and 7.0% Hispanics. Childhood overweight was defined as BMI ≥95th percentile for age and sex. Maternal prepregnancy obesity was determined as BMI ≥30 kg/m². The duration of breast‐feeding was measured as the weeks of age from birth when breast‐feeding ended. Results: After adjusting for potential confounders, children whose mothers were obese before pregnancy were at a greater risk of becoming overweight [adjusted odds ratio (OR), 4.1; 95% confidence interval (CI), 2.6, 6.4] than children whose mothers had normal BMI (<25 kg/m²; p < 0.001 for linear trend). Breast‐feeding for ≥4 months was associated with a lower risk of childhood overweight (OR, 0.6; 95% CI, 0.4, 1.0; p = 0.06 for linear trend). The additive interaction between maternal prepregnancy obesity and lack of breast‐feeding was detected (p < 0.05), such that children whose mothers were obese and who were never breast‐fed had the greatest risk of becoming overweight (OR, 6.1; 95% CI, 2.9, 13.1). Discussion: The combination of maternal prepregnancy obesity and lack of breast‐feeding may be associated with a greater risk of childhood overweight. Special attention may be needed for children with obese mothers and lack of breast‐feeding in developing childhood obesity intervention programs.     

Influence of calendar period on the association between BMI and coronary heart disease: A meta‐analysis of 31 cohorts

Objective:

The association between obesity and coronary heart disease (CHD) may have changed over time, for example due to improved pharmacological treatment of CHD risk factors. This meta‐analysis of 31 prospective cohort studies explores the influence of calendar period on CHD risk associated with body mass index (BMI).

Design and Methods:

The relative risks (RRs) of CHD for a five‐BMI‐unit increment and BMI categories were pooled by means of random effects models. Meta‐regression analysis was used to examine the influence of calendar period (>1985 v ≤1985) in univariate and multivariate analyses (including mean population age as a covariate).

Results:

The age, sex, and smoking adjusted RR (95% confidence intervals) of CHD for a five‐BMI‐unit increment was 1.28(1.22:1.34). For underweight, overweight and obesity, the RRs (compared to normal weight) were 1.11(0.91:1.36), 1.31(1.22:1.41), and 1.78(1.55:2.04), respectively. The univariate analysis indicated 31% (95%CI: ?56:0) lower RR of CHD associated with a five‐BMI‐unit increment and a 51% (95%CI: ?78: ?14)) lower RR associated with obesity in studies starting after 1985 (n = 15 and 10, respectively) compared to studies starting in or before 1985 (n = 16 and 10). However, in the multivariate analysis, only mean population age was independently associated with the RRs for a five‐BMI‐unit increment and obesity (?29(95%CI: ?55: ?5)) and ?31(95%CI: ?66:3), respectively) per 10‐year increment in mean age).

Conclusion:

This study provides no consistent evidence for a difference in the association between BMI and CHD by calendar period. The mean population age seems to be the most important factor that modifies the association between the risk of CHD and BMI, in which the RR decreases with increasing age.

     

Effects of a School‐based Weight Maintenance Program for Mexican‐American Children: Results at 2 Years

The prevalence of childhood overweight has increased significantly, with the highest rates noted among Mexican Americans. Many negative health outcomes are associated with overweight; thus, there is a need for effective weight‐loss interventions tailored to this group. This study evaluated 24‐month outcomes of a randomized, controlled trial involving an intensive lifestyle‐based weight maintenance program targeting overweight Mexican‐American children at a charter school in Houston, Texas. A total of 60 children (33 males, 55%) between the ages of 10 and 14 at or >85th percentile for BMI were recruited. Participants were randomized to an instructor‐led intervention (ILI) or a self‐help (SH) program, both aimed at modifying eating and physical activity behaviors using behavior modification strategies. Changes in participants' standardized BMI (zBMI) were assessed at baseline, 1, and 2 years. Tricep skinfold, total cholesterol, triglycerides, high‐density lipoprotein cholesterol, and calculated low‐density lipoprotein were assessed at baseline and 1 year. ILI participants showed significantly greater decreases in zBMI at 1 and 2 years (F = 26.8, P < 0.001, F = 4.1, P < 0.05, respectively) compared to SH controls. ILI participants showed greater improvements in body composition, as measured by tricep skinfold (F = 9.75, P < 0.01). Children in the ILI condition experienced benefits with respect to total cholesterol (F = 7.19, P < 0.05) and triglycerides (F = 4.35, P < 0.05) compared to children in the SH condition. Overall, the school‐based intervention resulted in improved weight and clinical outcomes in overweight Mexican‐American children, and zBMI was maintained over 2 years.     

Severely Obese Have Greater LPS‐stimulated TNF‐α Production Than Normal Weight African‐American Women

Obesity is associated with an increase in chronic, low‐grade inflammation which has been implicated in the development of type 2 diabetes mellitus and cardiovascular disease. The purpose of this study was to determine whether obesity was associated with an elevation of whole blood lipopolysaccharide (LPS)‐stimulated tumor necrosis factor‐α (TNF‐α) production. African‐American women were recruited from a larger study and assigned to one of five groups based on BMI: normal weight (NORM; BMI 20–25, n = 7), overweight (OVER; BMI 25–30, n = 12), class 1 obese (OB1; BMI 30–35, n = 19), class 2 obese (OB2; BMI 35–40, n = 10), or class 3 obese (OB3; BMI >40, n = 17). Body composition was determined via a whole body dual‐energy X‐ray absorptiometry (DXA) scan. Venous blood samples were collected following an overnight fast (>8 h), and stimulated with five doses of LPS (Salmonella enteriditis): 80, 40, 20, 10, and 5 µg/ml for 24 h in a 37 °C, 5% CO₂ incubator. Following stimulation, TNF‐α was measured using enzyme‐linked immunosorbent assay. OB3 produced 365% more TNF‐α than NORM at an LPS dose of 20 µg/ml (P < 0.05). When maximal TNF‐α production was assessed regardless of LPS dose, OB3 produced 230% more than NORM and OVER produced 190% more than NW (P = 0.001). Total and trunk fat mass and BMI were significantly correlated with maximal TNF‐α production and LPS = 20 µg/ml. Our findings are consistent with previous reports suggesting a relationship between increased adiposity and inflammatory marker production. This is one of the first studies to focus on African‐American women, who have higher rates of obesity.     

Characteristics Associated With Fasting Appetite Hormones (Obestatin,Ghrelin, and Leptin)

Obestatin, derived from the same gene as the hunger hormone ghrelin, may reduce food intake in animals. The role of obestatin in human physiology is unclear. We evaluated cross‐sectional associations between participant characteristics and fasting levels of obestatin as well two other hormones associated with energy balance, ghrelin and leptin. Data are from the baseline visit of the Optimal Macronutrient Intake Trial to Prevent Heart Disease (OMNI‐Heart) Trial that enrolled adults with elevated blood pressure (systolic 120–159 mm Hg or a diastolic of 80–99 mm Hg) but who were otherwise healthy. Partial Spearman's correlations and linear regression models estimated the association between age, gender, BMI, physical activity, and smoking with fasting hormones. Obestatin was directly associated with ghrelin (r = 0.45, P < 0.05). On average, overweight (BMI 25–30) and obese (BMI > 30) individuals had obestatin concentrations that were 12.6 (s.d. 8.8) and 25.4 (s.d. 8.4) pg/ml lower compared to normal weight (BMI < 25) individuals, respectively (P for trend = 0.002). Overweight (BMI 25–30) and obese (BMI > 30) individuals had ghrelin concentrations that were 161.7 (s.d. 69.6) and 284.7 (s.d. 66.5) pg/ml lower compared to normal weight (BMI < 25) individuals, respectively (P for trend <0.0001). A 5 unit increase in BMI was associated with 41.3% (s.d. 4.3%) (P < 0.0001) higher leptin. Obestatin and ghrelin are directly correlated and share the same patterns of association with participant characteristics. Modifiable risk factors for chronic diseases, such as BMI, are associated with fasting levels of leptin, obestatin, and ghrelin.     

The Association between Weight Perception and BMI among High School Students

Objective: To assess the association between weight perception and BMI among a large, diverse sample of adolescents. This study used both measured and self‐reported height and weight to calculate BMI. Research Methods and Procedures: A convenience sample of students (n = 2032) in grades 9 through 12 completed a questionnaire assessing demographic characteristics, self‐reported height and weight, and body weight perception. These students were then weighed and had their height measured using a standard protocol. Results: Using BMI calculated from measured height and weight, 1.5% of students were classified as underweight or at risk for underweight, 51.2% of students were normal weight, and 47.4% were overweight or at risk for overweight. Among this same sample of students, however, 34.8% perceived themselves as underweight, 42.9% perceived themselves as about the right weight, and 22.3% perceived themselves as overweight. Even when using BMI calculated from self‐reported height and weight, >20% of students who were overweight or at risk for overweight perceived themselves as underweight. Discussion: Because perception of overweight is a key determinant of adolescent nutritional habits and weight management, many students who are overweight or at risk for overweight but who do not perceive themselves as such are unlikely to engage in weight control practices. Increasing awareness of medical definitions of overweight might improve accuracy of weight perceptions and lead to healthier eating and increased physical activity.     

Obesity and Quality of Life: Mediating Effects of Pain and Comorbidities

Objective: To estimate the association between body mass index (BMI) and health‐related quality of life (HRQL) and examine whether joint pain and obesity‐related comorbidities mediate the BMI‐HRQL association. Research Methods and Procedures: Population‐based survey data from the 1999 Behavioral Risk Factor Surveillance Survey. Adults (N = 155, 989) were classified according to BMI as underweight (<18.5 kg/m²), desirable weight (18.5 to 24.9 kg/m²), overweight (25 to 29.9 kg/m²), obese class I (30 to 34.9 kg/m²), obese class II (35 to 39.9 kg/m²), and obese class III (≥40 kg/m²). Data including general health status, unhealthy days in the past 30 caused by physical problems and mental problems, and total unhealthy days in the past 30 were collected. Results: After adjusting for age, sex, race, smoking, education, and income, we observed J‐shaped associations between BMI and HRQL. Compared with desirable weight adults, underweight, overweight, and obesity classes I, II, and III adults [odds ratio (OR) = 1.57, 1.19, 1.95, 2.72, and 4.36, respectively] were significantly (p < 0.001) more likely to report fair/poor general health status. For unhealthy days caused by physical problems, the corresponding ORs were 1.51, 1.15, 1.66, 2.27, and 3.61 (p < 0.001). For unhealthy days caused by mental problems, the ORs were 1.35, 1.14 1.43, 1.57, and 2.25 (p < 0.001). For total unhealthy days, the corresponding ORs were 1.27, 1.09, 1.37, 1.73, and 2.46 (p < 0.01). Adding joint pain and obesity‐related comorbidities into models attenuated BMI‐HRQL associations. Discussion: Associations between BMI and HRQL indices were J‐shaped. Joint pain and comorbidities may mediate BMI‐HRQL associations.     

Single‐nucleotide Polymorphism of CD36 Locus and Obesity in European Adolescents

CD36 is a membrane receptor with a wide variety of functions, including the regulation of energy metabolism, fat storage, and adipocyte differentiation. To assess the relationship between CD36 gene single‐nucleotide polymorphisms (SNPs) and obesity in adolescents, we evaluated the relationship between CD36 SNPs and the risk of obesity in a case–control study composed of 307 obese (age = 15.0 ± 1.1 years) and 339 normal‐weight adolescents (age = 14.6 ± 1.1 years). To validate the results, we assessed the relation between the same SNPs and percentage of body fat (BF%) and BMI in 1,151 European adolescents (age = 14.8 ± 1.4 years). SNPs with a minor allele frequency >0.10 were selected to tag CD36. Genotyping was performed on an Illumina system. Four SNPs (rs3211867, rs3211883, rs3211908, and rs1527483) were associated with increased risk of obesity in the case–control study (odds ratio (OR) (95% confidence interval)): 1.96 (1.26–3.04], P = 0.003; 1.73 (1.16–2.59), P = 0.007; 2.42 (1.47–4.01), P = 0.0005 and 1.95 (1.25–3.05), P = 0.003, respectively). The same four SNPs were associated with higher BMI (P < 0.05) and BF% (P < 0.04) in the validation study. Further analyses identified a haplotype (frequency: 0.05) carrying the minor allele of these SNPs as being associated with obesity (OR: 2.28; P = 0.0008) in the case–control study and with excess adiposity (i.e., higher BF% (P = 0.03) and BMI (P = 0.04)) in the validation study. Our data suggest that genetic variability at the CD36 gene locus could be associated with body weight variability in European adolescents but these findings require replication.     

Relationship between Body Weight Gain and Significant Knee,Hip, and Back Pain in Older Americans

Objective: To examine the association between BMI (kilograms per meter squared) and reports of significant knee, hip, and back pain using data from a nationally representative sample of U.S. adults 60 years or older. Research Methods and Procedures: Population‐based survey data from the Third National Health and Nutrition Examination Survey, involving 5724 adults 60 years or older, were used. BMI, calculated from measured weight (kilograms) and height (meters squared), was used to categorize participants into six BMI‐defined groups: underweight (<18.5), desirable weight (18.5 to 24.9), overweight (25 to 29.9), obese class I (30 to 34.9), obese class II (35 to 39.9), and obese class III (≥40). The presence of significant knee, hip, and back pain in the groups was studied. Results: The overall prevalences of knee, hip, and back pain were 21%, 14%, and 22%, respectively. Prevalence estimates for knee (underweight 12.1% to obesity class III 55.7%), hip (underweight 10.4% to obesity class III 23.3%), and back (underweight 20.2% to obesity class III 26.1%) pain increased with increased BMI. Sex‐, race‐, and age‐specific pain prevalence estimates also generally increased at increased levels of BMI. Discussion: Among U.S. adults 60 years or older, the prevalence of significant knee, hip, and back pain increases with increased levels of BMI.