Seasonal variation of lean arm fat and fat arm area among Ellisras population from childhood to young adulthood

Abstract

Overweight and obesity continue to be major public health problem in Africa. The risks of over-weight and obesity are associated with potentially negative impacts on children’s health, growth and development in later life. This study aimed to investigate the seasonal variation of upper arm lean and fat areas from childhood to young adulthood among the rural population of Ellisras (now called Lephalale), South Africa. Mid-upper arm circumference (MUAC), triceps and biceps skinfold measurements were measured according to standard anthropometric procedures. The measurements were collected during the autumn and spring seasons from 1999 to 2003. Anthropometric measurements of the participants (752 boys and 998 girls, aged 4 to 17 years) who completed the survey in 2003 were used to calculate their total upper-arm area (TUA), arm fat area (AFA) and arm muscle area (AMA). Data were analysed using the Mann-Whitney U test to examine sex and age differences in the participants’ anthropometric characteristics. The healthy percentile ranges by sex and age were used to categorise the cut-off points. The generalised estimate equation (GEE) was used to test the relationships between the data on AFA, AMA and MUAC obtained in autumn and spring of the years when the surveys were conducted. The prevalence of overweight and obesity was relatively low in AFA, AMA and MUAC. A significant (p-value = 0.020) positive association in AFA for boys aged between 8 – 11 years (β = 0.47; 95% CL: 0.07; 0.82) and girls of the same age (p-value = 0.001), β = 1.30 (95% CL: 0.58; 2.03) in spring as compared to autumn were found. Furthermore, there was a significant median association between AFA and AMA, in autumn and spring. In conclusion, seasonal variation in the development of fat and lean arm areas among the Ellisras children was observed over time from mid-childhood to adolescence. Longitudinal studies on seasonal variation in anthropometric and biochemical variables that focus on conventional methods for estimating obesity are needed.