Changes in skinfold thickness and body composition among children and adolescents in Shandong, China from 1995 to 2010.

BACKGROUND: There is strong evidence of a upward secular trend in skinfold thickness (SFT) and the prevalence of obesity has increased substantially over recent decades in developed countries. However, no studies on this trend have been reported in Shandong Province, China. The present study aimed to assess the decennial change in SFT and body composition among children and adolescents in Shandong Province during the past 15 years (1995-2010). METHODS: Data were obtained from two national surveys on student's constitution and health carried out by the government in 1995 and 2010 in Shandong Province, China. A total of 14 780 (7198 in 1995 and 7582 in 2010) students aged 7-18 years participated in the present study. Weight and SFT of all subjects were measured. Percentage body fat (%FM) was estimated by SFT, and fat mass (FM) and fat-free mass (FFM) were calculated from: FM (kg) = %FM × weight (kg)/100; FFM (kg) = weight (kg)-FM(kg). The range of differences of weight, SFT, FM and FFM over the different age groups between the 1995 and 2010 samples were calculated. RESULTS: In the past 15 years, mean values of SFT have increased. The mean (range) increments of SFT were 6.28 (2.91-11.22) mm for boys and 3.29 (2.22-4.29) mm for girls, demonstrating a mean increase of 32% for boys and 14% for girls. The mean (range) increments of weight, FM and FFM were 7.26 (4.41-10.82) kg, 3.70 (1.47-6.58) kg and 3.56 (1.24-5.27) kg, at rates of 18%, 47% and 10% for boys, respectively, and 4.14 (2.78-5.64) kg, 1.68 (1.02-2.27) kg and 2.46 (1.52-3.49) kg, at rates of 11%, 20% and 8% for girls, respectively. CONCLUSIONS: The mean values of SFT, FM and FFM have increased over time. Rates of increase were greater for FM than FFM.