Dietary fiber and saturated fat intake associations with cardiovascular disease differ by sex in the Malmö Diet and Cancer Cohort: a prospective study

Abstract

Background: The aim of the study was to examine associations between intake of macronutrients and dietary fiber and incident ischemic cardiovascular disease (iCVD) in men and women.

Methods: We used data from 8,139 male and 12,535 female participants (aged 44-73 y) of the Swedish population-based Malmö Diet and Cancer cohort. The participants were without history of CVD and diabetes mellitus, and had reported stable dietary habits in the study questionnaire. Diet was assessed by a validated modified diet history method, combining a 7-d registration of cooked meals and cold beverages, a 168-item food questionnaire (covering other foods and meal patterns), and a 1-hour diet interview. Sociodemographic and lifestyle data were collected by questionnaire. iCVD cases, which included coronary events (myocardial infarctions or deaths from chronic ischemic heart disease) and ischemic strokes, were ascertained via national and local registries. Nutrient-disease associations were examined by multivariate Cox regressions.

Results: During a mean follow-up of 13.5 years, we identified 1,089 male and 687 female iCVD cases. High fiber intakes were associated with lower incidence rates of iCVD in women and of ischemic stroke in men. In post-hoc analysis, we discovered statistically significant interactions between intake of fiber and saturated fat; these interactions also differed between men and women (p<0.001).

Conclusions: In this well-defined population, a high fiber intake was associated with lower risk of iCVD, but there were no robust associations between other macronutrients and iCVD risk. Judging from this study, gender-specific nutrient analysis may be preferable in epidemiology.

Figure 1. Joint effects of saturated fat and fiber intake on iCVD risk, men.

Joint effects of quintiles of energy-adjusted saturated fat and fiber intake on risk of ischemic cardiovascular disease in men of the MDC cohort, expressed as hazard ratios. The numbers given in the figure are those significantly different (p<0.05) from the reference category (F5/SFA1). p value for the interaction between fiber and saturated fat = 0.041. Adjusted for age, method version, total energy intake (continuous), season, BMI class, smoking category, education, alcohol category, systolic blood pressure, antihypertensive treatment, antilipemic treatment and leisure time physical activity (quartiles). RR:s calculated with no individual nutrient variables in the model due to redundancy.

Figure 2. Joint effects of saturated fat and fiber intake on iCVD risk, women.

Joint effects of quintiles of energy-adjusted saturated fat and fiber intake on risk of ischemic cardiovascular disease in women of the MDC cohort, expressed as hazard ratios. The numbers given in the figure are those significantly different (p<0.05) from the reference category (F5/SFA1). p value for the interaction between fiber and saturated fat = 0.003. Adjusted for age, method version, total energy intake (continuous), season, BMI class, smoking category, education, alcohol category, systolic blood pressure, antihypertensive treatment, antilipemic treatment and leisure time physical activity (quartiles). RR:s calculated with no individual nutrient variables in the model due to redundancy.