Weight status change from childhood to early adulthood and the risk of adult hypertension :

To determine whether the U.S. Centers for Disease Control and Prevention (CDC; CDC Reference) or International Obesity Task Force (IOTF; IOTF Reference) BMI cut-off points for classifying adiposity status in children are more effective at predicting future health risk. The sample (N=1709) included 4- to 15-year-old (at baseline) boys and girls from the Bogalusa Heart Study. Overweight and obesity status were determined using both the CDC Reference and IOTF Reference BMI cut-off points at baseline. The ability of childhood overweight and obesity, determined from the two BMI classification systems, to predict obesity and metabolic disorders in young adulthood (after a 13- to 24-year follow-up) was then compared. Independently of the classification system employed to determine adiposity based on childhood BMI, the odds of being obese and having all of the metabolic disorders in young adulthood were significantly (p<0.05) higher in the overweight and obese groups by comparison with the nonoverweight groups. Childhood overweight and obesity, determined by both the CDC Reference and IOTF Reference, had a low sensitivity and a high specificity for predicting obesity and metabolic disorders in young adulthood. Overweight and obesity as determined by the CDC Reference were slightly more sensitive and slightly less specific than the corresponding values based on the IOTF Reference. Overweight and obesity during childhood, as determined by both the CDC and IOTF BMI cut-off points, are strong predictors of obesity and coronary heart disease risk factors in young adulthood. The differences in the predictive capacity of the CDC Reference and IOTF Reference are, however, minimal.

The contribution of body mass index (BMI) at different life stages to adult blood pressure (BP) is not well known. We investigated whether changes in BMI across childhood and adulthood, and birthweight, influence BP in mid-adulthood. In 9297 participants in the 1958 British birth cohort, we analysed BMI measures at several ages (7, 11, 16, 33 and 45 years) and BP at 45 years. Positive BMI/BP associations strengthened with age; at 45 years a standard deviation (SD) increase in concurrent BMI was associated with an increase in systolic blood pressure (SBP) of 3.9 mmHg [95% confidence interval (CI) 3.6-4.2] and an elevated risk of hypertension (odds ratio 1.68; 95% CI 1.60-1.76). The effect of concurrent BMI on BP strengthened with decreasing childhood BMI; among the thinnest 10% at 11 years, SBP increased by 5.5 mmHg per SD increase in concurrent BMI; among the heaviest 10% the increase was 3.3 mmHg. Excessive BMI gain, especially recently, was associated with raised BP; allowing for BMI at 33 years, a SD increase in BMI between 33 and 45 years was associated with an SBP increase of 4.1 mmHg (95% CI 3.6-4.6). Birthweight was inversely associated with BP; SBP reduced by 1.3 mmHg (95% CI 0.9-1.7) per SD increase in birthweight, independently of BMI. High BMI and excessive BMI gain at any life stage, particularly recently, is associated with increased adult BP. Relatively thin children were vulnerable to BMI gain and increased BP in adulthood. Elevated BP associated with low birthweight was not caused by 'catch-up' growth.

To estimate associations between alternative measures of childhood adiposity and indicators of cardio-metabolic health in adulthood, both unadjusted and adjusted for changes in adiposity from childhood to adulthood. The study consisted of a 20-year follow-up of 2188 adults who had participated in the 1985 Australian Schools Health and Fitness Survey when they were between 7 and 15 years of age. Baseline and follow-up measures of body composition included height and weight, waist and hip circumferences and skinfold thicknesses at four sites. At follow-up, participants attended study clinics where component indicators of the metabolic syndrome (MetS) (waist circumference, blood pressure, fasting blood glucose and lipids) were measured. Waist circumference and skinfold measures were the strongest predictors of subsequent MetS (2009 Joint Scientific Statement definition) in early adulthood. For example, relative risks (RRs) for children in the highest (vs lowest) quarter of waist circumference were 4.8 (95% confidence interval (CI): 2.5-9.2) for males and 5.8 (95% CI: 2.4-14.2) for females. After adjusting for change in waist circumference from childhood to adulthood, each 10 cm increase in childhood waist circumference was associated with an approximate twofold increase in risk for adult MetS (RR = 2.1 (95% CI: 1.7-2.7) among males and RR = 2.3 (95% CI: 1.6-3.4) among females). Elevated waist circumference and skinfold thickness measures in childhood appear to be the strongest predictors of subsequent MetS in early adulthood. The increased risk associated with higher waist circumference in childhood appears to be independent of changes in waist circumference from childhood to adulthood.