Monetary cost of dietary energy is negatively associated with BMI and waist circumference, but not with other metabolic risk factors, in young Japanese women.

OBJECTIVE Little is known about the relationship of dietary cost to health status. The present cross-sectional study examined the association between the monetary cost of dietary energy (Japanese yen/4184 kJ) and several metabolic risk factors. DESIGN Monetary cost of dietary energy was estimated based on dietary intake assessed by a self-administered diet history questionnaire and retail food prices. Body height and weight, from which BMI was derived, waist circumference and blood pressure were measured and fasting blood samples were collected for biochemical measurements. SETTING A total of fifteen universities and colleges in Japan. SUBJECTS A total of 1136 female Japanese dietetic students aged 18-22 years. RESULTS After adjustment for potential confounding factors, monetary cost of dietary energy was significantly and negatively associated with BMI (P for trend = 0.0024). Monetary cost of dietary energy also showed a significant and negative association with waist circumference independently of potential confounding factors, including BMI (P for trend = 0.0003). No significant associations were observed for other metabolic risk factors examined (P for trend = 0.10-0.88). CONCLUSIONS The monetary cost of dietary energy was independently and negatively associated with both BMI and waist circumference, but not other metabolic risk factors, in a group of young Japanese women.