Table 3. Adjusted relative risks (RRs) (and 95% confidence intervals) of insulin resistance across tertiles of dietary vitamin C intake in the Harbin People’s Health Study (HPHS, 2008–2012) and in the Harbin Cohort Study on Diet, Nutrition and Chronic Non-communicable Diseases (HDNNCDS, 2010–2012).
| Tertiles of dietary vitamin C intake (mg/day) | Ptrend | |||
|---|---|---|---|---|
| HPHS | ||||
| Diabetic participants(n = 117) | <57.26 | ≥57.26–103.18 | ≥103.18 | |
| No. of cases | 23 | 16 | 20 | |
| Age and sex-adjusted relative risk | 1.00 | 0.36(0.14–0.94) | 0.52(0.20–1.35) | 0.48 |
| Multivariate relative risk1 | 1.00 | 0.17(0.05–0.66) | 0.29(0.08–1.08) | 0.37 |
| Non-diabetic participants(n = 1,621) | <70.53 | ≥70.53–115.57 | ≥115.57 | |
| No. of cases | 74 | 91 | 90 | |
| Age and sex-adjusted relative risk | 1.00 | 0.93(0.65–1.34) | 1.08(0.76–1.53) | 0.56 |
| Multivariate relative risk1 | 1.00 | 0.96(0.64–1.45) | 0.88(0.69–1.02) | 0.049 |
| HDNNCDS | ||||
| Diabetic participants(n = 239) | <61.71 | ≥61.71–104.33 | ≥104.33 | |
| No. of cases | 40 | 42 | 41 | |
| Age and sex-adjusted odds ratio | 1.00 | 0.88(0.69–0.99) | 0.87(0.61–1.25) | 0.43 |
| Multivariate odds ratio2 | 1.00 | 0.84(0.58–0.95) | 0.78(0.51–1.19) | 0.22 |
| Non-diabetic participants(n = 4,349) | <68.42 | ≥68.42–111.30 | ≥111.30 | |
| No. of cases | 315 | 352 | 309 | |
| Age and sex-adjusted odds ratio | 1.00 | 1.03(0.86–1.23) | 0.84(0.70–1.00) | 0.034 |
| Multivariate odds ratio2 | 1.00 | 0.997(0.82–1.21) | 0.82(0.67–1.01) | 0.043 |
1Adjusted for age at study recruitment, sex, body mass index, waist circumference, exercise regularly, total energy intake, hypertension, coronary heart disease, and hyperlipemia.
2Adjusted for age at study recruitment, sex, body mass index, waist circumference, exercise regularly, total energy intake, hypertension, coronary heart disease, hyperlipemia, body fat percentage, education, current smoking, and family history of type 2 diabetes.