[Relationship between protein intake and body mass index and waist circumference in Chinese adults using quantile regression analysis].

OBJECTIVE: To study the relationship between dietary protein intake and body mass index( BMI) and waist circumference under the distribution of different quantile.

METHODS: The data of adult residents of 12 provinces from Chinese Health and Nutrition Survey in 2011 were used to analyze the relationship between protein intake and BMI and waist circumference by quantile regression analysis.

RESULTS: There were 11800 subjects in total, 5623( 47. 7%) were male, the average age was( 51. 5 ± 15. 1) years old, for female, 6177( 52. 3%) and( 51. 9 ± 15. 0) years old, respectively. The protein intake was( 1. 1 ± 0. 4) g/kg BW in men and( 1. 0 ± 0. 4) g/kg BW in women. Significant sex differences were found in waist circumference, energy, protein intake, carbohydrate intake, smoking, drinking and working status, activity and educational level( P < 0. 05), but there were no significant difference between male and female in age, BMI, fat intake and urban rural ratio. After sex-stratified, the result of the regression analysis showed that quantile regression coefficients adjusting for other confounders between protein intake and BMI and waist circumference both in male and female, and the parallelism test for regression coefficient at different quantile were statistically significant( P < 0. 05).

CONCLUSION: Under the distribution of different quantile, dietary protein intake is negatively correlated with BMI and waist circumference, and there is a descending trend, which means that protein intake has a greater impact on population with higher BMI and higher waist circumference.