Associations of low-carbohydrate and low-fat intakes with all-cause mortality in subjects with prediabetes with and without insulin resistance

Abstract

Background & aims: We investigated the associations of low-carbohydrate and low-fat diets with all-cause mortality in people with prediabetes according to insulin resistance status using data from the National Health and Nutrition Examination Survey (NHANES).

Methods: We analyzed the NHANES participants with prediabetes from 2005 to 2008, and their vital status was linked to the National Death Index through the end of 2011. Low-carbohydrate and low-fat diets were defined as ≦40% and ≦30% of calories from carbohydrate and fat, respectively. The homeostasis model assessment of insulin resistance (HOMA-IR) was used to determine insulin resistance. Weighted Cox proportional hazards regression models were used to compare the hazard ratios for the associations of low-carbohydrate and low-fat diets with all-cause mortality.

Results: Among the 1687 participants with prediabetes, 96 of them had died after a median follow-up of 4.5 years. Participants with a HOMA-IR >3.0 had an increase in all-cause mortality compared with those who had a HOMA-IR ≦3.0 (HR 1.797, 95% CI 1.110 to 2.909, p = 0.019). Participants with ≦40% of calories from carbohydrate and >30% from fat (3.75 per 1000 person-years) had a lower all-cause mortality rate compared with those who had >40% from carbohydrate and >30% from fat (10.20 per 1000 person-years) or >40% from carbohydrate and ≦30% from fat (8.09 per 1000 person-years), with statistical significance observed in those who had a HOMA-IR ≦3.0.

Conclusions: A low-carbohydrate intake (≦40%) was associated with a lower all-cause mortality rate in people with prediabetes.

Keywords: Insulin resistance; Low-carbohydrate; Low-fat; Mortality; NHANES.