Objective  To analyze the prevalence of diabetes mellitus among middle-aged and older rural adults of Xinxiang county, Henan Province and its correlation with dietary patterns.

  Methods  The study was done based on the data collected from a cross-sectional survey of Xinxiang County, which was part of the Prospective Cohort Study on the Common Chronic Non-Communicable Diseases in Rural areas of Henan Province. Randomized cluster sampling was used to select adult respondents (≥18 years old) from among the residents of 17 villages in Xinxiang county. The respondents completed questionnaires, and underwent physical examinations and laboratory tests between April, 2017 and June, 2017. A total of 7604 individuals aged between 45 and 79 were included in our study. Dietary patterns were established through factor analysis and the dietary pattern factor scores were divided into quartiles (Q1-Q4). The relationship between dietary patterns and diabetes mellitus was analyzed with multivariate logistic regression model.

  Results  Out of the total of 7604 middle-aged and older rural adults in Xinxiang County, Henan Province, 1604 had diabetes mellitus, suggesting a 21.1% prevalence of diabetes mellitus. Factor analysis was used to establish four dietary patterns, namely animal-based diet, vegetable-egg diet, mixed diet and traditional diet. Subjects of these four dietary patterns displayed different demographic characteristics. There were no statistical difference in anthropometricor clinical indicators between the quartile with the lowest dietary pattern factor score (Q1) and the quartile with the highest dietary pattern factor score (Q4) for subjects with animal-based diet (P>0.05). Compared with those in the Q1 quartile of vegetable-egg diet, subjects in the Q4 quartile of vegetable-egg diet showed lower levels of high-density lipoprotein cholesterol (HDL-C), along with different distribution of fasting blood glucose (FBG), showing statistically significant difference (P<0.05). In comparison to subjects in Q1 quartile of mixed diet, those in Q4 quartile showed lower levels of systolic blood pressure (SBP), the difference being statistically significant (P<0.05). In the traditional diet group, subjects in the Q4 quartile had lower waist circumference (WC), but higher levels of HDL-C than those of subjects in Q1 quartile. In addition, the distribution of glycated-hemoglobin (HbA1c) and FBG were different, the difference being statistically significant (P<0.05). The results of multivariate logistic regression analysis demonstrated that traditional diet could be a protective factor of diabetes mellitus (odds ratio OR=0.810, 95%CI: 0.690-0.952, P_trend<0.05) after adjusting for multiple confounding factors.

  Conclusion  The prevalence of diabetes in middle-aged and older rural residents is relatively high in Xinxiang County, Henan Province, and there may be a protective relationship between traditional diet and diabetes mellitus.