Nut consumption and risk of type II diabetes in the Physicians' Health Study

Background/Objectives: While type II diabetes (DM) is a major cause of morbidity in the United States, limited data are available on the association between nut intake and incident DM. We sought to examine the association between nut consumption and the risk of DM. Subjects/Methods: Prospective cohort of 20 224 male participants of the Physicians' Health Study I. Nut consumption was estimated using a 19-item brief food frequency questionnaire, and incident DM was ascertained through yearly follow-up questionnaires. Cox regression was used to estimate relative risks of DM. Results: The average age of the study participants was 54.4+/-9.4 years (range: 40.7-87.1). During a mean follow-up of 19.2 years, 1828 cases of DM occurred. The crude incidence rates of DM were 4.82, 4.85, 4.92, 4.16, 4.29 and 3.32 cases per 1000 person-years for individuals reporting nut consumption of rarely/never, <1, 1, 2-4, 5-6 and 7+ servings per week, respectively. While nut consumption was associated with a lower risk of DM in a model adjusted for age (P for tend 0.017), such relation was attenuated on additional control for other confounders (multivariable adjusted hazard ratios (95% confidence interval) for DM were 1.0 (reference), 1.06 (0.93-1.20), 1.10 (0.95-1.26), 0.97 (0.82-1.14), 0.99 (0.76-1.30) and 0.87 (0.61-1.24) from the lowest to the highest category of nut consumption, respectively (P for trend 0.99). No statistically significant association between nut consumption and DM was found in either lean or overweight/obese participants. Conclusions: Our data do not show an association between nut consumption and incident DM in US male physicians. European Journal of Clinical Nutrition (2010) 64, 75-79; doi:10.1038/ejcn.2009.121; published online 16 September 2009