White rice intake and incidence of type-2 diabetes: analysis of two prospective cohort studies from Iran

Abstract

BackgroundRefined grains and white rice have been associated with elevated risk of type 2 diabetes mellitus (T2DM). In this study, we sought to quantify the effect of white rice intake on incident T2DM in two prospective population-based cohort studies from Iran, where white rice is one of the main staple.MethodsWe used follow-up data from 9,182 participants from Golestan Cohort Study (GCS, 2004–2007, conducted mainly in rural areas) and 2,173 from Tehran Lipid and Glucose Study (TLGS, 2004–2006) who did not have T2DM and other chronic diseases at baseline. Diet was assessed using validated food frequency questionnaires. Multivariable logistic regression models were used to estimate adjusted odds ratios (ORs) for incident T2DM.ResultsWe documented 902 new cases of T2DM in GCS and 81 in TLGS. Age-standardized cumulative incidence of T2DM was 9.9% in Golestan and 8.0% in Tehran. Daily white rice intake was significantly higher among residents of Tehran compared to Golestan (median daily intake: 250 vs. 120 grams; P-value < 0.001). After adjustment for potential confounders, there was no significant association between daily white rice intake and incident T2DM in GCS. In TLGS, the adjusted OR (95% confidence interval (CI)) was 2.1 (1.1, 3.9) comparing participants with daily white rice intake of >250 grams/day to those with <250.ConclusionsWe observed an increased lieklihood of T2DM associated with high white rice intake among residents of Tehran and no association in Golestan. Our findings, if further supported by other studies, have important public health implications especially for countries where white rice is a major staple and diabetes is increasing rapidly incidence is high. Further research is needed to investigate lack of an association between lower levels of white rice intake and T2DM.Electronic supplementary materialThe online version of this article (doi:10.1186/s12889-016-3999-4) contains supplementary material, which is available to authorized users.

White Rice Intake and Incident Diabetes: A Study of 132,373 Participants in 21 Countries

“…Data from two prospective studies from Iran reported opposing results ( 21 ). While data from Tehran showed significantly higher risk for >250 g/day of white rice, the Golestan Cohort Study showed no significant increase in risk at 210 g/day intake of white rice ( 21 ).…”

“…Data from two prospective studies from Iran reported opposing results ( 21 ). While data from Tehran showed significantly higher risk for >250 g/day of white rice, the Golestan Cohort Study showed no significant increase in risk at 210 g/day intake of white rice ( 21 ). A lack of association between white rice intake and incident diabetes was also reported in a study conducted in southern Spain ( 22 ).…”

“…By contrast, a large prospective cohort study of >45,000 participants from Singapore reported that higher consumption of white rice (above 500 g/day) did not substantially increase the risk of incident diabetes ( 19 ). Two different cohort studies from Iran also showed opposing results with one showing an increased risk while the other did not ( 21 ). Many of these studies were conducted in single countries and predominantly in Asia where consumption of white rice is higher than most other regions of the world.…”

Impact of 3-year changes in lipid parameters and their ratios on incident type 2 diabetes: Tehran lipid and glucose study

“…Mente et al recently showed that increased carbohydrate intake is associated with lower LDL-C and HDL-C and also higher TG and TC/HDL-C ratio [ 48 ]. Additionally, among Iranians, intake of carbohydrate, especially white rice, that was associated with incident T2DM, is high [ 49 ]. Third, because physical activity level was assessed with the lipid research clinic in the first phase of the TLGS and by the modifiable activity questionnaire from the 2nd phase [ 23 ], we did not enter this variable in our data analysis, although physical inactivity was not shown as an independent predictor for incident T2DM among Tehranian adults [ 4 ].…”

Excessive carbohydrate consumption and body mass index: the risk factors for type 2 diabetes mellitus in patients with Prader-Willi syndrome in Tamil Nadu population

“…Likewise, another study revealed that the GI of white rice depends on the proportion of the amylose content of the grain in addition to the cooking time, and the GI value of white rice has been reported to be higher than that of brown rice and other whole grains (Foster-Powell, Holt, & Brand-Miller, 2002). Other two prospective cohort studies in Iran observed a doubling of diabetes risk associated with > 250 g of white rice intake in Tehran Lipid and Glucose Study (TLGS) when compared to Golestan Cohort Study (GCS) (Golozar et al, 2017). Similarly, our current study has reported that individuals with PWS highly consumed white rice (1071 g, 1370 kcal/day) matched with another daily intake of foods.…”