Nut Consumption in Relation to Cardiovascular Disease Incidence and Mortality Among Patients With Diabetes Mellitus

Abstract

Rationale: The evidence regarding the potential health benefits of nut consumption among individuals with type 2 diabetes mellitus is limited.

Objective: To examine intake of total and specific types of nuts, including tree nuts and peanuts, in relation to subsequent risk of cardiovascular disease (CVD), including coronary heart disease and stroke, and all-cause and cause-specific mortality among individuals with diabetes mellitus.

Methods and results: This prospective analysis included 16 217 men and women with diabetes mellitus at baseline or diagnosed during follow-up (Nurses' Health Study: 1980-2014, Health Professionals Follow-Up Study: 1986-2014). Nut consumption was assessed using a validated food frequency questionnaire and updated every 2 to 4 years. During 223 682 and 254 923 person-years of follow-up, there were 3336 incident CVD cases and 5682 deaths, respectively. Higher total nut consumption was associated with a lower risk of CVD incidence and mortality. The multivariate-adjusted hazard ratios (95% CIs) for participants who consumed 5 or more servings of total nuts per week (1 serving=28 g), compared with those who consumed <1 serving per month, were 0.83 (0.71-0.98; P trend=0.01) for total CVD incidence, 0.80 (0.67-0.96; P trend=0.005) for coronary heart disease incidence, 0.66 (0.52-0.84; P trend <0.001) for CVD mortality, and 0.69 (0.61-0.77; P trend <0.001) for all-cause mortality. Total nut consumption was not significantly associated with risk of stroke incidence or cancer mortality. For specific types of nuts, higher tree nut consumption was associated with lower risk of total CVD, coronary heart disease incidence, and mortality because of CVD, cancer, and all causes, whereas peanut consumption was associated with lower all-cause mortality only (all P trend <0.001). In addition, compared with participants who did not change the consumption of total nuts from pre- to post-diabetes mellitus diagnosis, participants who increased consumption of total nuts after diabetes mellitus diagnosis had an 11% lower risk of CVD, a 15% lower coronary heart disease risk, a 25% lower CVD mortality, and a 27% lower all-cause mortality. The associations persisted in subgroup analyses stratified by sex/cohort, body mass index at diabetes mellitus diagnosis, smoking status, diabetes mellitus duration, nut consumption before diabetes mellitus diagnosis, or diet quality.

Conclusions: Higher consumption of nuts, especially tree nuts, is associated with lower CVD incidence and mortality among participants with diabetes mellitus. These data provide novel evidence that supports the recommendation of incorporating nuts into healthy dietary patterns for the prevention of CVD complications and premature deaths among individuals with diabetes mellitus.

Keywords: cardiovascular disease; diabetes mellitus; diet; epidemiology; mortality; nuts.

Figure 1.. Hazard ratios (95% CIs) of CVD incidence and mortality according to types of nut consumption after diabetes diagnosis*

* Multivariate hazard ratio for CVD incidence and mortality among study participants who consumed nuts two or more servings per week versus those who consumed nuts less than one serving per month were adjusted for age (continuous), diabetes duration (years), sex (men or women), Caucasian (yes/no), BMI at diabetes diagnosis (<23.0, 23.0-24.9, 25.0-29.9, 30.0-34.9, ≥35.0 kg/m²), physical activity (<3.0, 3.0-8.9, 9.0-17.9, 18.0-26.9, ≥27.0 MET-hours/week), smoking status (never, past, current 1-14 cigarettes/day, current ≥15 cigarettes/day), alcohol consumption (0, 0.1-4.9, 5.0-14.9, ≥15.0 g/day), current aspirin use (yes/no), family history of MI or cancer (yes/no), presence of hypertension (yes/no), use of lipid-lowering medication (yes/no), diabetes medication use (insulin, oral medication, or others), and intake of total energy, red or processed meat, fruits, and vegetables (all in quartiles).

Figure 2.. Associations between total and tree nut consumption and CVD incidence and CVD mortality *

* Hazard ratios were adjusted for age (continuous), diabetes duration (years), sex (men or women), Caucasian (yes/no), BMI at diabetes diagnosis (<23.0, 23.0-24.9, 25.0-29.9, 30.0-34.9, ≥35.0 kg/m²), physical activity (<3.0, 3.0-8.9, 9.0-17.9, 18.0-26.9, ≥27.0 MET-hours/week), smoking status (never, past, current 1-14 cigarettes/day, current ≥15 cigarettes/day), alcohol consumption (0, 0.1-4.9, 5.0-14.9, ≥15.0 g/day), family history of MI or cancer (yes/no), current aspirin use (yes/no), presence of hypertension (yes/no), use of lipid-lowering medication (yes/no), diabetes medication use (insulin, oral medication, or others), and intake of total energy, red or processed meat, fruits, and vegetables (all in quartiles). All P for non-linearity were <0.001.

Figure 3.. Hazard ratios (95% CIs) of CVD incidence and mortality according to changes in consumption of total nuts, tree nuts, and peanuts before and after diabetes diagnosis*

* Multivariable analyses were adjusted for age (continuous), diabetes duration (years), sex (men or women), Caucasian (yes/no), family history of MI or cancer (yes/no), hypertension status (no hypertension, new hypertension, always hypertension), lipid-lowering medication use (never user, new user, always user), aspirin use (never user, new user, always user), changes in smoking status (always never smoker, always past smoker, always current smoker, quit smoking after diabetes diagnosis, others), changes in physical activity (tertiles), changes in alcohol consumption (tertiles), changes in body mass index (tertiles), changes in total caloric intake (tertiles), changes in AHEI excluding nuts (tertiles), and nut consumption before diabetes diagnosis (continuous).