Relationship between salivary androstenedione levels, body composition and physical activity levels in young girls
Background: High androgenic activity in adolescent girls and adult women is associated with adiposity and metabolic disturbances. This study examined the relationship between salivary androstenedione levels, body composition, and physical activity levels in young girls. Method: Twenty-three girls (8.4 ± 0.9 years), nine of normal weight, and 14, overweight or obese, according to Centers for Disease Control and Prevention body mass index (BMI) percentile ranking, wore an ActiGraph® accelerometer for five days. Skin folds were measured for percentage body fat and fat-free mass calculation. Saliva samples were collected at home, three times in one day (upon waking, 30 minutes post-waking and in the evening). Previously published cut-points estimated the minutes of sedentary behaviour, light, moderate, moderate-to-vigorous, vigorous, and very vigorous physical activity. Meeting physical activity recommendations was defined as accumulating 60 minutes/day of moderate-to-vigorous physical activity. T-tests, correlation analysis, and analysis of variance, examined the relationships among the variables (alpha = p-value ≤ 0.05). Results: Thirty-five per cent of the girls met current physical activity recommendations. There were no differences between the normal weight and overweight or obese categories in terms of meeting physical activity recommendations, or salivary androstenedione levels. Evening salivary androstenedione levels were higher among girls who did not meet the physical activity recommendations (116.9 ± 15.3 pg/ml vs. 80.45 ± 8.5 pg/ml, p-value = 0.04). Salivary androstenedione levels at 30 minutes post-waking were positively correlated with BMI (r = 0.45, p-value = 0.03) and percentage body fat (r = 0.40, p-value = 0.05). Conclusion: These research results were similar to those of circulating androgen research performed in adolescent girls and adult women, in that salivary androstenedione levels were positively correlated with BMI and percentage body fat in young girls. Meeting physical activity recommendations was associated with the maintenance of the normal diurnal rhythm of salivary androstenedione secretion.
Keywords: androstenedione, obesity, physical activity, women, girls