[Relationship between dietary vitamin C and Type 2 diabetes]

To examine the correlation between dietary vitamin C intake and Type 2 diabetes.

A total of 5 168 participants from Xiangya Hospital, Central South University were randomly selected. According to the vitamin C intake, the participants were divided into 5 groups: a Q1 group (n=1 033), a Q2 group (n=1 034), a Q3 group (n=1 034), a Q4 group (n=1 034) and a Q5 group (n=1 033). They were also divided into a Type 2 diabetes group (n=502) and a non-diabetes group (n=4 666). The height, weight, and blood pressure were measured, and vitamin C intake and other dairy consumption were evaluated using a food frequency questionnaire and fasting plasma glucose (FPG). The analysis of variance (ANOVA), Chi-square test, Mann-Whitney U test and logistic regression model were used to analyze the relationship between dietary vitamin C and Type 2 diabetes.

The univariate analysis showed that there were significant differences in the vitamin C consumption in energy intake, activity level, dietary fiber intake, nutritional supplementation status, drinking or not drinking, education level among the different vitamin C intake groups (all P<0.05). There were also significant differences in age, sex, body mass index (BMI), smoking status and vitamin C intake between the Type 2 diabetes group and the non-diabetes group (all P<0.05). After the adjustment for age, gender, hypertension, energy intake or smoking status, the multiple logistic regression model found that the multivariable adjusted OR was 0.610 (95% CI 0.428-0.870) for 
the highest level of vitamin C intake (>154.78 mg/d) in comparison with the lowest level (≤ 63.26 mg/d). The results suggested that the vitamin C intake was inversely associated with the Type 2 diabetes (r=-0.029, P<0.05).

There is a significant negative correlation between the dietary vitamin C intake and the risk of Type 2 diabetes.