29.11.11

Childhood Adiposity, Adult Adiposity, and Cardiovascular Risk Factors

Markus Juonala, M.D., Ph.D., Costan G. Magnussen, Ph.D., Gerald S. Berenson, M.D., Alison Venn, Ph.D., Trudy L. Burns, M.P.H., Ph.D., Matthew A. Sabin, M.D., Ph.D., Sathanur R. Srinivasan, Ph.D., Stephen R. Daniels, M.D., Ph.D., Patricia H. Davis, M.D., Wei Chen, M.D., Ph.D., Cong Sun, M.D., Ph.D., Michael Cheung, M.D., Ph.D., Jorma S.A. Viikari, M.D., Ph.D., Terence Dwyer, M.D., M.P.H., and Olli T. Raitakari, M.D., Ph.D.

N Engl J Med 2011; 365:1876-1885

Background: Obesity in childhood is associated with increased cardiovascular risk. It is uncertain whether this risk is attenuated in persons who are overweight or obese as children but not obese as adults.

Methods: We analyzed data from four prospective cohort studies that measured childhood and adult body-mass index (BMI, the weight in kilograms divided by the square of the height in meters). The mean length of follow-up was 23 years. To define high adiposity status, international age-specific and sex-specific BMI cutoff points for overweight and obesity were used for children, and a BMI cutoff point of 30 was used for adults.

Results: Data were available for 6328 subjects. Subjects with consistently high adiposity status from childhood to adulthood, as compared with persons who had a normal BMI as children and were nonobese as adults, had an increased risk of type 2 diabetes (relative risk, 5.4; 95% confidence interval [CI], 3.4 to 8.5), hypertension (relative risk, 2.7; 95% CI, 2.2 to 3.3), elevated low-density lipoprotein cholesterol levels (relative risk, 1.8; 95% CI, 1.4 to 2.3), reduced high-density lipoprotein cholesterol levels (relative risk, 2.1; 95% CI, 1.8 to 2.5), elevated triglyceride levels (relative risk, 3.0; 95% CI, 2.4 to 3.8), and carotid-artery atherosclerosis (increased intima–media thickness of the carotid artery) (relative risk, 1.7; 95% CI, 1.4 to 2.2) (P≤0.002 for all comparisons). Persons who were overweight or obese during childhood but were nonobese as adults had risks of the outcomes that were similar to those of persons who had a normal BMI consistently from childhood to adulthood (P>0.20 for all comparisons).

Conclusions: Overweight or obese children who were obese as adults had increased risks of type 2 diabetes, hypertension, dyslipidemia, and carotid-artery atherosclerosis. The risks of these outcomes among overweight or obese children who became nonobese by adulthood were similar to those among persons who were never obese. (Funded by the Academy of Finland and others.)

28.11.11

Effectiveness of Interventions Aimed at Reducing Screen Time in Children
A Systematic Review and Meta-analysis of Randomized Controlled Trials
Gita Wahi, MD, FRCPC; Patricia C. Parkin, MD, FRCPC; Joseph Beyene, PhD; Elizabeth M. Uleryk, BA, MLS; Catherine S. Birken, MD, MSc, FRCPC
Arch Pediatr Adolesc Med. 2011;165(11):979-986. doi:10.1001/archpediatrics.2011.122
Objective  To evaluate the impact of interventions focused on reducing screen time.
Data Sources  Medline, Embase, Cochrane Central Register of Controlled Trials, PsycINFO, ERIC, and CINAHL through April 21, 2011.
Study Selection  Included studies were randomized controlled trials of children aged 18 years or younger with interventions that focused on reducing screen time.
Intervention  Efforts to reduce screen time.
Main Outcome Measures  The primary outcome was body mass index (BMI); the secondary outcome was screen time (hours per week).
Results  A total of 1120 citations were screened, and 13 studies were included in the systematic review. Study samples ranged in age (3.9-11.7 years) and size (21-1295 participants). Interventions ranged in length (1-24 months) and recruitment location (5 in schools, 2 in medical clinics, 1 in a community center, and 5 from the community). For the primary outcome, the meta-analysis included 6 studies, and the difference in mean change in BMI in the intervention group compared with the control group was –0.10 (95% confidence interval [CI], –0.28 to 0.09) (P = .32). The secondary outcome included 9 studies, and the difference in mean change from baseline in the intervention group compared with the control group was –0.90 h/wk (95% CI, –3.47 to 1.66 h/wk) (P = .49). A subgroup analysis of preschool children showed a difference in mean change in screen time of –3.72 h/wk (95% CI, –7.23 to –0.20 h/wk) (P = .04).
Conclusions  Our systematic review and meta-analysis did not demonstrate evidence of effectiveness of interventions aimed at reducing screen time in children for reducing BMI and screen time. However, interventions in the preschool age group hold promise.