Stability of the Association between Birth Weight and Childhood Overweight during the Development of the Obesity Epidemic

Objective: To assess whether changes in the birth weight distribution or changes in the association of birth weight with the later risk of childhood overweight have contributed to the development of the obesity epidemic. Research Methods and Procedures: A Danish population‐based cohort study of 124,615 girls and 128,346 boys (ages 6 to 13 years), born between 1936 and 1983, were studied. Birth weight and annual measurements of height and weight were obtained from school health records. Overweight was defined by BMI in relation to internationally accepted criteria. The relative risk of being overweight by birth weight was calculated separately for each age, sex, and time period. Results: The birth weight distribution remained relatively stable over time. Compared with children with a birth weight of 3.0 to 3.5 kg, the risk of overweight increased consistently with each increase in birth weight category among girls and boys and at all ages between 6 and 13 years. Furthermore, the association between birth weight and increased risk of overweight in childhood remained stable across a 48‐year period. Discussion: The increase in the prevalence of overweight could not be explained by time trends in the distribution of birth weight or by changes in the association between birth weight and the later risk of overweight over time. This implies that, unless the prenatal environment influences the later risk of overweight without increasing birth weight, the environmental influences contributing to the obesity epidemic in children of school age operate in the early postnatal period.     

Headaches in overweight children and adolescents referred to a tertiary-care center in Israel

Objective: To assess the association between obesity and primary headaches in children and adolescents. Methods and Procedures: In a prospective study, the short‐questionnaire version based on existing International Headache Society diagnostic criteria was administered. Two hundred and seventy‐three children and adolescents (61% females) aged 9–17 years were assessed. One hundred and sixteen (42.5%) subjects were of normal weight, 45 (16.5%) were at risk for overweight (BMI >85th and <95th percentile for age and gender) and 112 (41%) were overweight (BMI ≥95th percentile). The outcome measures were prevalence of headaches, type of headaches, association between headaches and elevated blood pressure in overweight subjects. Results: Headache was reported in 39 (14.3%) subjects, with a similar rate in females (14.5%) and males (14%). Among 39 subjects with headaches, 20 (17.9%) were overweight, 7 (15.6%) were at risk for overweight and 12 (10.3%) were normal‐weight children. Among females, 7.7% of normal‐weight group suffered from headaches, compared with 14.8% of the at risk for overweight group and 20.3% of the overweight group (P for trend 0.04). Among males, the occurrence of headaches was similar in all three weight groups (P = 0.96). The occurrence of headaches increased from 10.6% among children aged 9–11 years to 21.8% in the 15–18 years age group (P < 0.05). In multivariate analysis, a significant independent risk for headaches was present in overweight females (odds ratio (OR) = 3.93, 95% confidence interval (CI) 1.28–12.1) and in adolescents aged 15–18 years (OR = 2.62, 95% CI 1.07–6.45). Elevated blood pressure was not independently associated with headaches. Of the 15 children with migraine, 12 were either at risk for overweight or overweight. Discussion: Overweight females had an almost fourfold excess risk of headaches when compared with normal‐weight girls.     

Rapid infant weight gain predicts childhood overweight

Objective : To determine among a contemporary cohort whether rapid weight gain between birth and 6 months is associated with risk of childhood overweight and if this risk differs by ethnicity and/or breast‐feeding history. Research Methods and Procedures : This was a cross‐sectional survey in 1999 to 2000 of parents/guardians of children participating in the Special Supplemental Nutrition Program for Women, Infants, and Children in New York State. Measurements were abstracted by chart review, including weight at birth and 6 months, and height and weight at time of survey and every 6 months subsequently. Overweight at 4 years of age was defined as a BMI ≥ 95th age‐ and sex‐specific percentiles. Results : The study sample was 32% Hispanic, 19% black, and 49% white; 17% of children were overweight. Rate of infant weight gain (expressed in terms of 100 g/mo) was significantly associated with being overweight at 4 years (odds ratio, 1.4; 95% confidence interval, 1.3 to 1.6 after adjusting for history of breast‐feeding, birth weight, and ethnicity). The odds of being overweight at 4 years of age for Hispanic children were twice those of non‐Hispanic children (odds ratio, 2.2; 95% confidence interval, 1.5 to 3.3). The population‐attributable risk of overweight at 4 years of age was 19% for children in the highest quintile of infant weight gain. Discussion : Among this contemporary, multi‐ethnic cohort, rapid infant weight gain was associated with increased risk of being overweight at 4 years of age, independently of potential confounders. Identification of the risk factors contributing to rapid weight gain during infancy might improve early recognition and guide strategies for optimal nutrition to prevent the development of childhood overweight.     

Hepatic steatosis and low cardiorespiratory fitness in youth with type 2 diabetes

The purpose of this study was to examine the association between cardiorespiratory fitness, ectopic triglyceride accumulation, and insulin sensitivity among youth with and without type 2 diabetes. Subjects included 137 youth ages 13-18 years including 27 with type 2 diabetes, 97 overweight normoglycemic controls, and 13 healthy weight normoglycemic controls. The primary outcome measure was cardiorespiratory fitness defined as peak oxygen uptake indexed to fat free mass. Secondary outcomes included liver and muscle triglyceride content determined by (1)H-magnetic resonance spectroscopy and insulin sensitivity determined by frequently sampled intravenous glucose tolerance test. Despite similar measures of adiposity, peak oxygen uptake was 11% lower (38.9 ± 7.9 vs. 43.9 ± 6.1 ml/kgFFM/min, P = 0.002) and hepatic triglyceride content was nearly threefold higher (14.4 vs. 5.7%, P = 0.001) in youth with type 2 diabetes relative to overweight controls. In all 137 youth, cardiorespiratory fitness was negatively associated with hepatic triglyceride content (r = -0.22, P = 0.02) and positively associated with insulin sensitivity (r = 0.29, P = 0.002) independent of total body and visceral fat mass. Hepatic triglyceride content was also negatively associated with insulin sensitivity (r = -0.35, P < 0.001), independent of adiposity, sex, age, and peak oxygen uptake. This study demonstrated that low cardiorespiratory fitness and elevated hepatic triglyceride content are features of type 2 diabetes in youth. Furthermore, cardiorespiratory fitness and hepatic triglyceride are associated with insulin sensitivity in youth. Taken together, these data suggest that cardiorespiratory fitness and hepatic steatosis are potential clinical biomarkers for type 2 diabetes among youth.     

Nut consumption and weight gain in a Mediterranean cohort: The SUN study

Objective: To assess the association, in a Mediterranean population, between nut consumption and risk of weight gain (at least 5 kg) or the risk of becoming overweight/obese. Research Methods and Procedures: The Seguimiento Universidad de Navarra project is a prospective cohort of 8865 adult men and women who completed a follow‐up questionnaire after a median of 28 months. Dietary habits were assessed with a previously validated semiquantitative food‐frequency questionnaire. Results: Nine hundred thirty‐seven participants reported a weight gain of ≥5 kg at follow‐up. After adjusting for age, sex, smoking, leisure time physical activity, and other known risk factors for obesity, participants who ate nuts two or more times per week had a significantly lower risk of weight gain (odds ratio: 0.69; 95% confidence interval: 0.53 to 0.90, p for trend = 0.006) than those who never or almost never ate nuts. Participants with little nut consumption (never/almost never) gained an average of 424 grams (95% confidence interval: 102 to 746) more than frequent nut eaters. Nut consumption was not significantly associated with incident overweight/obesity in the cohort. Discussion: Frequent nut consumption was associated with a reduced risk of weight gain (5 kg or more). These results support the recommendation of nut consumption as an important component of a cardioprotective diet and also allay fears of possible weight gain.     

Overweight in Adolescence Is Related to Increased Risk of Future Urothelial Cancer

Obesity has been linked to various malignancies, but a clear relation of overweight with urothelial cancer has not been established. We assessed the association between adolescent obesity and future risk for urothelial cancer. Medical data on 1,110,835 Israeli adolescents examined for fitness for military duty between 1967 and 2005 were linked to the National Cancer Registry in this nationwide population‐based cohort study. We used Cox proportional hazards modeling to estimate the covariate‐adjusted hazard ratio (HR) for urothelial cancer associated with BMI measured at age 17. The mean follow‐up of 17.6 ± 10.8 years reflected 19,576,635 person years, during which 661 examinees developed urothelial cancer of the bladder, ureter, or renal pelvis. BMI ≥85th standard percentile in adolescence significantly predicted increased risk of urothelial cancer with a HR (adjusted for year of birth, education and religiosity) of 1.42 (95% confidence interval (CI), 1.13–1.77, P = 0.002). Similar results were observed using the ≥25 kg/m² definition of overweight (HR = 1.36 (95% CI, 1.08–1.72), P = 0.008). Incidence of urothelial cancer was significantly lower in the more educated and among those who attended religious schools. Overweight in adolescence is related to increased risk of future urothelial cancer. In view of the growing incidence of both urothelial cancer and adolescent obesity, our study suggests an avenue for possible prevention of urothelial cancer.     

Lower than predicted resting metabolic rate is associated with severely impaired cardiorespiratory fitness in obese individuals

Obese individuals have reduced cardiorespiratory fitness as compared with leaner counterparts. Regular exercise maintains or increases fitness and lean body mass. Lean body mass, in turn, has a direct impact on resting metabolic rate (RMR). Given these relationships, we sought to evaluate the association between RMR and cardiorespiratory fitness in obese individuals. We evaluated 64 obese individuals (78% female) with direct assessment of RMR and cardiorespiratory fitness via breath‐by‐breath measurement of oxygen consumption and carbon dioxide production at rest and during exercise. The mean age and BMI were 47.4 ± 12.2 years and 47.2 ± 9.2 kg/m², respectively. The majority of subjects, 69%, had a measured RMR above that predicted by the Harris‐Benedict equation. Compared with the higher RMR group, those with a lower than predicted RMR had increased BMI, with values of 52.9 vs. 44.7 kg/m², P = 0.001, respectively. Analysis of those demonstrating significant effort during cardiopulmonary exercise testing (peak respiratory exchange ratio ≥1.10) revealed a significantly higher peak oxygen uptake (VO₂ peak) in the higher RMR group (17.3 ± 3.5 ml/min/kg) compared with the lower RMR group (13.6 ± 1.9 ml/min/kg), P = 0.003. In summary, a lower than predicted RMR was associated with a severely reduced VO₂ peak and a higher BMI in this cohort. These data suggest that morbid obesity may be a vicious cycle of increasing BMI, reduced cardiorespiratory fitness, muscle deconditioning, and lower RMR. Collectively, these responses may, over time, exacerbate the imbalance between energy intake and expenditure, resulting in progressive increases in body weight and fat stores.     

Weight cycling and 6-year weight change in healthy adults: The Aerobics Center Longitudinal Study

Objective: To determine the longitudinal relationship between a reported history of weight cycling and the trajectory of weight in a group of normal‐weight to obese women and men. Research Methods and Procedures: This was a clinic‐based cohort study conducted over 6 years. Subjects were healthy women (n = 141) and men (n = 797) age 20 to 78 years who completed at least four comprehensive medical exams at the Cooper Clinic (Dallas, TX) between 1987 and 2003. Weight loss history was reported, and body weight was measured at all examinations. Weight cycling status was derived from weight loss history and defined as ≥five episodes of weight loss of ≥2.3 kg/episode. Using linear mixed effects models, weight at each examination was regressed on weight cycling status separately for women and men while controlling for selected covariables. Results: Baseline BMI was 23 and 21 kg/m² among cycling and non‐cycling women and was 27 and 25 kg/m² among cycling and non‐cycling men, respectively. We observed a non‐significant difference (p = 0.09) in women by cycling status (average weight gain = 0.5 and 0.2 kg/yr among cyclers and non‐cyclers, respectively) and no difference in weight gain over time among men by cycling status (average weight gain = 0.2 kg/yr among both groups, p = 0.99). Higher baseline cardiorespiratory fitness level and increased fitness over the follow‐up were associated with attenuated weight gain in both women and men. Discussion: In healthy, middle‐aged individuals, a history of weight cycling does not seem to increase the risk of long‐term weight gain in men; however, this relation needs to be studied further in women.     

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.     

Dietary fat and weight gain among women in the Nurses' Health Study

Objective: To assess the association of dietary fat and weight gain among adult women and to investigate whether offspring of overweight parents have a greater predisposition to weight gain due to intake of dietary fat. Research Methods and Procedures: This was an 8‐year follow‐up of 41,518 women in the Nurses’ Health Study (NHS), a population‐based, prospective cohort. The women were 41 to 68 years of age, free of cardiovascular disease, cancer, and diabetes in 1986 when “baseline” weight and diet were assessed. Eight years later (1994), changes in weight and dietary intake were assessed. Linear regression models were used to relate change in weight to fat intake and change in fat intake, using the percentage of energy from carbohydrate as the comparison, adjusted for age, BMI in 1986, leisure time physical activity, time spent sitting, percent of calories from protein, and change in percentage of calories from protein. Results: Overall, there was a weak positive association between total fat intake (β = 0.11) and weight gain. Increases in monosaturated and polyunsaturated fat were not associated with weight gain, but increases in animal fat, saturated fat, and trans fat had a positive association with weight change. There was not strong evidence of effect modification by parental weight status (p = 0.7 to 0.8 for percentage of calories from total fat, animal fat, and vegetable fat); however, the associations were stronger among the overweight compared with leaner women (p < 0.05 for percentage of calories from each type of fat). Among overweight women, for every one percentage increase in percentage of calories from trans fat, women gained an additional 2.3 lb (95% confidence interval, 1.80 to 2.86). Conclusion: Our results show that, overall, percent of calories from fat has only a weak positive association with weight gain; however, percentage of calories from animal, saturated, and trans fat has stronger associations. There was no clear evidence that the diet‐weight gain association was stronger among offspring of overweight parents, but dietary fat was associated with greater weight gain among overweight 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.     

RETRACTION: C-reactive Protein and Metabolic Syndrome in Youth: A Strong Relationship?

Retraction: Note from the Editor‐in‐Chief: This paper is retracted Objective: Metabolic syndrome (MS) is on the rise in youth. As high‐sensitivity C‐reactive protein (hs‐CRP) is associated with cardiovascular/metabolic disorders, we evaluated the association between MS and its components and hs‐CRP in a sample of Brazilian overweight and obese youth. Methods and Procedures: A total of 407 students (229 girls, 273 with excessive weight, 11.3 ± 3.2 years) were evaluated. Measurement included BMI, waist circumference (WC), blood pressure, lipids, insulin, and hs‐CRP. Excessive weight was defined using BMI z ‐score; MS by the modified National Cholesterol Education Program—Adult Treatment Panel III. Results: Subjects were classified into two groups: with MS (n = 72) and without (n = 335). hs‐CRP means and medians were higher in MS group (1.41 mg/l vs. 1.06 mg/l, P < 0.001; 2.21 mg/l vs. 1.23 mg/l, P < 0.001). Associations between hs‐CRP quartiles and insulin resistance (IR) (P < 0.001), MS (P < 0.001), WC (P < 0.000), BMI z‐score (P < 0.001), hypertension (P < 0.001), hypertriglyceridemia (P < 0.001), and low HDL‐c (P = 0.023) were significant; adjustment of hs‐CRP for BMI z‐score eliminated the previous association, except for the number of MS components (nMSc) (P < 0.001). Adjusting for homeostasis model assessment method of IR (HOMA‐IR) did not eliminate the relation between hs‐CRP and MS components. Furthermore, increases in BMI z ‐score and nMSc were associated with an increased hs‐CRP. Excessive weight (odds ratio (OR), 7.9; confidence interval (CI), 4.7–13.4; P = 0.000), hypertension (OR, 2.3; CI, 1.3–4.2; P = 0.003), and hypertriglyceridemia (OR, 2.3; CI, 1.5–3.7; P < 0.001) were independently associated with hs‐CRP. Discussion: In youth, hs‐CRP is strongly related with MS and its components, and is also determined by the body composition. This association indicates a precocious proinflammatory state.     

Reverse causality and confounding and the associations of overweight and obesity with mortality

Objective: To examine the effect of reverse causality and confounding on the association of BMI with all‐cause and cause‐specific mortality. Research Methods and Procedures: Data from two large prospective studies were used. One (a community‐based cohort) included 8327 women and 7017 men who resided in two Scottish towns at the time of the baseline assessment in 1972–1976; the other (an occupational cohort) included 4016 men working in the central belt of Scotland at the time of the baseline assessment in 1970–1973. Participants in both cohorts were ages 45 to 64 years at baseline; the follow‐up period was 28 to 34 years. Results: In age‐adjusted analyses that did not take account of reverse causality or smoking, there was no association between being overweight (BMI 25 to <30 kg/m²) and mortality, and weak to modest associations between obesity (BMI ≥30 kg/m²) and mortality. There was a strong association between smoking and lower BMI in women and men in both cohorts (all p < 0.0001). Among never‐smokers and with the first 5 years of deaths removed, overweight was associated with an increase in all‐cause mortality (relative risk ranging from 1.12 to 1.38), and obesity was associated with a doubling of risk in men in both cohorts (relative risk, 2.10 and 1.96, respectively) and a 60% increase in women (relative risk, 1.56). In both never‐smokers and current smokers, being overweight or obese was associated with important increases in the risk of cardiovascular disease. Discussion: These findings demonstrate that with appropriate control for smoking and reverse causality, both overweight and obesity are associated with important increases in all‐cause and cause‐specific mortality, and in particular with cardiovascular disease mortality.     

A prospective study of breakfast consumption and weight gain among U.S. men

Objective: The aim was to investigate the association between breakfast consumption and long‐term weight gain in an adult male population. Research Methods and Procedures: We evaluated prospective data on 20,064 U.S men, 46 to 81 years of age, who participated in the Health Professionals Follow‐up Study. Data on body weight, dietary factors, and lifestyle variables were obtained by validated questionnaires. We examined weight gain during 10 years of follow‐up. Results: Overall, 5857 men had a weight gain of 5 kg or greater during 10 years of follow‐up. Breakfast consumption was inversely associated with the risk of 5‐kg weight gain after adjustment for age [hazard ratio (HR) = 0.77 (95% confidence interval [CI], 0.72 to 0.82)], and this association was independent of lifestyle and BMI at baseline [HR = 0.87 (95% CI, 0.82 to 0.93)]. Fiber and nutrient intakes partially explained the association between breakfast consumption and weight gain. The inverse association between breakfast consumption and weight gain was more pronounced in men with a baseline BMI of 25 kg/m² or lower [multivariate HR = 0.78 (95% CI, 0.70 to 0.87)] than in men who were overweight at baseline [HR = 0.92 (95% CI, 0.85 to 1.00)]. Furthermore, we observed that an increasing number of eating occasions in addition to three standard meals was associated with a higher risk of 5‐kg weight gain [HR = 1.15 (95% CI, 1.06 to 1.25, for ≥2 vs. 0 additional eating occasions)]. Discussion: These findings suggest that the consumption of breakfast may modestly contribute to the prevention of weight gain as compared with skipping breakfast in middle‐aged and older men.     

The extended relationship between child cardiovascular risks and academic performance measures

Objective: To examine the relationship between children's overweight status and other cardiovascular risk fitness factors and academic performance among fifth‐grade students. Research Methods and Procedures: Using a sample of 968 fifth‐grade students (50.7% boys; mean age = 10.6 years), children's cardiovascular risks (BMI, blood pressure, acanthosis nigricans) and fitness measures were compared with their mean group performance scores across four subscales (mathematics, reading/language arts, science, and social studies) of a statewide standardized academic performance test. Results: Of this sample, 39% were either at risk for being overweight or were already overweight; slightly over one half were of normal weight. Initial findings revealed a significant relationship between children's weight category and their reading/language arts, mathematics, and science test scores even after controlling for a proxy of socioeconomic status. When additional cardiovascular risk and fitness measures were included in the model, however, children's BMI status had no association. Instead, a composite fitness index, children's blood pressure, sex, and proxy of socioeconomic status were significantly associated with children's academic test scores. Discussion: This study expanded our understanding of the connection between children's overweight risks and academic performance by examining the impact of other cardiovascular risk factors such as high blood pressure and measures of fitness. These findings support the development and implementation of childhood cardiovascular risk surveillance programs that evaluate not only children's overweight risks but also their fitness, risk for type 2 diabetes, and/or high blood pressure by showing a relationship between some of these risks and children's academic test performance.     

Dietary Intake of Whole and Refined Grain Breakfast Cereals and Weight Gain in Men

Objective: Prospective studies have suggested that substituting whole grain for refined grain products may lower the risk of overweight and obesity. Breakfast cereal intake is a major source of whole and refined grains and has also been associated with having a lower BMI. The aim of this study was to prospectively assess the association between whole and refined grain breakfast cereal intakes and risk of overweight (BMI ≥ 25 kg/m²) and weight gain. Research Methods and Procedures: We examined 17, 881 U.S. male physicians 40 to 84 years of age in 1982 who were free of cardiovascular disease, diabetes mellitus, and cancer at baseline and reported measures of breakfast cereal intake, weight, and height. Results: Over 8 and 13 years of follow‐up, respectively, men who consumed breakfast cereal, regardless of type, consistently weighed less than those who consumed breakfast cereals less often (p value for trend = 0.01). Whole and refined grain breakfast cereal intake was inversely associated with body weight gain over 8 years, after adjustment for age, smoking, baseline BMI, alcohol intake, physical activity, hypertension, high cholesterol, and use of multivitamins. Compared with men who rarely or never consumed breakfast cereals, those who consumed ≥1 serving/d of breakfast cereals were 22% and 12% less likely to become overweight during follow‐up periods of 8 and 13 years (relative risk, 0.78 and 0.88; 95% confidence interval, 0.67 to 0.91 and 0.76 to 1.00, respectively). Discussion: BMI and weight gain were inversely associated with intake of breakfast cereals, independently of other risk factors.     

Overweight is associated with decreased cognitive functioning among school-age children and adolescents

Objective: Childhood overweight and obesity have increased substantially in the past two decades, raising concerns about their psychosocial and cognitive consequences. We examined the associations between academic performance (AP), cognitive functioning (CF), and increased BMI in a nationally representative sample of children. Methods and Procedures: Participants were 2,519 children aged 8–16 years, who completed a brief neuropsychological battery and measures of height and weight as a part of the Third National Health and Nutrition Examination Survey, a cross‐sectional survey conducted between 1988 and 1994. Z‐scores were calculated for each neuropsychological test, and poor performance was defined as z‐score <2. Results: The association between BMI and AP was not significant after adjusting for parental/familial characteristics. However, the associations between CF remained significant after adjusting for parental/familial characteristic, sports participation, physical activity, hours spent watching TV, psychosocial development, blood pressure, and serum lipid profile. Z‐scores on block design (a measure of visuospatial organization and general mental ability) among overweight children and children at risk of overweight were below those of normal‐weight children by 0.22 (s.e. = 0.16) and 0.10 (s.e. = 0.10) unit, respectively (P for trend <0.05). The odds of poor performance on block design were 1.97 (95% confidence interval: 1.01–3.83) and 2.80 (1.16–6.75), respectively, among children at risk or overweight compared to normal‐weight peers. Discussion: Increased body weight is independently associated with decreased visuospatial organization and general mental ability among children. Future research is needed to determine the nature, persistence, and functional significance of this association.     

Fatness, fitness, and insulin sensitivity among 7- to 9-year-old children

Objective: The purpose of this study was to examine the relationships among fatness and aerobic fitness on indices of insulin resistance and sensitivity in children. Research Design and Methods: A total of 375 children (193 girls and 182 boys) 7 to 9 years of age were categorized by weight as normal‐weight, overweight, or obese and by aerobic fitness based on a submaximal physical working capacity test (PWC). Fasting blood glucose (GLU) and insulin (INS) were used to calculate various indices of insulin sensitivity (GLU/INS), the homeostasis model assessment (HOMA), and the quantitative insulin sensitivity check index (QUICKI). Surrogate measures of pancreatic β cell function included the insulinogenic index (INS/GLU) and the HOMA estimate of pancreatic β‐cell function (HOMA %B). Results: Insulin sensitivity and secretion variables were significantly different between the normal‐weight children and the overweight and obese subjects. Fasting insulin (FI), HOMA, QUICKI, and INS/GLU were significantly different between the overweight and obese subjects. Likewise, the high fitness group possessed a better insulin sensitivity profile. In general, the normal‐weight–high fit group possessed the best insulin sensitivity profile and the obese‐unfit group possessed the worst insulin sensitivity profile. Several significant differences existed among the six fat‐fit groups. Of particular note are the differences within BMI groups by fitness level and the comparison of values between the normal‐weight–unfit subjects and the overweight and obese subjects with high fitness. Conclusions: The results indicate that aerobic fitness attenuates the difference in insulin sensitivity within BMI categories, thus emphasizing the role of fitness even among overweight and obese children.     

Lack of Association Between PCK1 Polymorphisms and Obesity,Physical Activity,and Fitness in European Youth Heart Study (EYHS)

Phosphoenolpyruvate carboxykinase‐1 (PCK1) is the rate‐limiting enzyme in the hepatic gluconeogenic pathway. Studies have shown that overexpression of Pck1 in mice results in obesity‐related traits and higher levels of physical activity (PA). Therefore, our aims were to investigate whether common genetic variation in the PCK1 gene influences obesity‐related traits, PA, and fitness, and to examine whether PA and fitness attenuate the influence of the PCK1 polymorphisms on obesity in children. Analyses were undertaken on data from Danish and Estonian children (958 boys and 1,104 girls) from the European Youth Heart Study (EYHS), a school‐based, cross‐sectional study of children (mean ± s.d. age: 9.6 ± 0.4 years) and adolescents (15.5 ± 0.5 years). We genotyped eight polymorphisms that captured the common genetic variations in the PCK1 gene. The association between the PCK1 polymorphisms and BMI, waist circumference (WC), sum of four skinfolds, PA, and fitness was tested using an additive model adjusted for age, age‐group, gender, maturity, and country. Interactions were tested by including interaction terms in the model. None of the polymorphisms were significantly associated with BMI, WC, sum of four skinfolds, PA, and fitness, and also with the risk of being overweight or obese (P > 0.05). The interactions between the polymorphisms and age‐group, gender, PA, and fitness were not statistically significant. This is the first study to comprehensively examine the association of PCK1 polymorphisms with obesity, PA, and fitness. Despite strong evidence from animal studies, our study in the EYHS cohort failed to identify an association of PCK1 polymorphisms with obesity, PA, and fitness.     

Sedentary behavior, recreational physical activity, and 7-year weight gain among postmenopausal U.S. women

Objective: To assess the relationship among recreational physical activity (PA), non‐occupational sedentary behavior, and 7‐year weight gain among postmenopausal U.S. women 40 to 69 years old. Research Methods and Procedures: In 1992 and 1999, 18,583 healthy female participants from the Cancer Prevention Study II Nutrition Cohort completed questionnaires on anthropometric characteristics and lifestyle factors. The associations between recreational PA [in metabolic equivalent (MET) hours per week] and non‐occupational sedentary behavior (in hours per day) at baseline and risk for 7‐year weight gain (5 to 9 or ≥10 vs. ±4 pounds) were assessed using multivariate logistic regression analysis. Results: Neither PA nor sedentary behavior was associated with a 5‐ to 9‐pound weight gain. Among women who were not overweight at baseline (BMI <25.0), the odds of ≥10‐pound weight gain were 12% lower (odds ratio, 0.88; 95% confidence interval, 0.77 to 0.99) for those in the highest category of recreational PA (≥18 MET h/wk) compared with >0 to <4 MET h/wk; odds were 47% higher (odds ratio, 1.47; 95% confidence interval, 1.21 to 1.79) for non‐overweight women who reported ≥6 h/d of non‐occupational sedentary behavior compared with <3 h/d. Neither PA nor sedentary behavior were associated with risk of ≥10‐pound weight gain weight among women who were overweight at baseline (BMI ≥25.0). Discussion: Both recreational PA and non‐occupational sedentary behavior independently predicted risk of ≥10‐pound weight gain among postmenopausal women who were not overweight at baseline. Public health messages to prevent weight gain among normal‐weight postmenopausal women may need to focus on decreasing time spent in sedentary behaviors and increasing the amount of time spent on PA.