[Influence of different dietary patterns on bone mineral density and body mass index of college freshmen in urban and rural areas of China].

Objective: To find out the differences of dietary patterns among freshmen coming from urban and rural areas that might have influenced their bone mineral density and body mass index (BMI).

Methods: With stratified random sampling method, dietary patterns and their bone mineral density, BMI of 1319 freshmen were studied.

Results: (1) The ratios of urban freshmen who chose "western food" pattern (χ(2) = 31.548, P = 0.000; χ(2) = 13.068, P = 0.001), "animal food" pattern (χ(2) = 8.279, P = 0.016; χ(2) = 41.137, P = 0.000) or "calcium food" pattern (χ(2) = 37.254, P = 0.000; χ(2) = 15.651, P = 0.000) were higher than that of rural freshmen, and the ratios of rural freshmen who chose "Chinese traditional" pattern (χ(2) = 36.194, P = 0.000; χ(2) = 25.936, P = 0.000) were higher than that of urban freshmen. (2) The average height, weight, BMI, speed of sound (SOS) of male freshmen from rural areas were lower than that from the city and the differences were statistically significant (P < 0.05). Among those female freshmen, only height and weight were significantly different (P < 0.05). (3) In both rural and urban freshmen, the factor scores of "western food" pattern had a positive correlation with BMI, with the correlation coefficients as 0.187, 0.192, 0.551, 0.465 (P < 0.001). The factor scores of "calcium food" pattern were positively related to bone mineral density (SOS values) with correlation coefficients as 0.680, 0.342, 0.841, 0.786, P < 0.001 respectively. The factor scores on "Chinese traditional" pattern were negatively correlated with BMI, with correlation coefficients as -0.223, -0.093 (P < 0.05) which were positively related to bone mineral density (SOS values) in both rural and urban male freshmen, with correlation coefficients as 0.905, 0.711 (P < 0.001).

Conclusion: Different dietary patterns chosen by urban and rural freshmen had a significant impact on both bone mineral density and BMI.