Associations of fat and carbohydrate intake with cardiovascular disease and mortality: prospective cohort study of UK Biobank participants

Abstract

Objective: To investigate the association of macronutrient intake with all cause mortality and cardiovascular disease (CVD), and the implications for dietary advice.

Design: Prospective population based study.

Setting: UK Biobank.

Participants: 195 658 of the 502 536 participants in UK Biobank completed at least one dietary questionnaire and were included in the analyses. Diet was assessed using Oxford WebQ, a web based 24 hour recall questionnaire, and nutrient intakes were estimated using standard methodology. Cox proportional models with penalised cubic splines were used to study non-linear associations.

Main outcome measures: All cause mortality and incidence of CVD.

Results: 4780 (2.4%) participants died over a mean 10.6 (range 9.4-13.9) years of follow-up, and 948 (0.5%) and 9776 (5.0%) experienced fatal and non-fatal CVD events, respectively, over a mean 9.7 (range 8.5-13.0) years of follow-up. Non-linear associations were found for many macronutrients. Carbohydrate intake showed a non-linear association with mortality; no association at 20-50% of total energy intake but a positive association at 50-70% of energy intake (3.14 v 2.75 per 1000 person years, average hazard ratio 1.14, 95% confidence interval 1.03 to 1.28 (60-70% v 50% of energy)). A similar pattern was observed for sugar but not for starch or fibre. A higher intake of monounsaturated fat (2.94 v 3.50 per 1000 person years, average hazard ratio 0.58, 0.51 to 0.66 (20-25% v 5% of energy)) and lower intake of polyunsaturated fat (2.66 v 3.04 per 1000 person years, 0.78, 0.75 to 0.81 (5-7% v 12% of energy)) and saturated fat (2.66 v 3.59 per 1000 person years, 0.67, 0.62 to 0.73 (5-10% v 20% of energy)) were associated with a lower risk of mortality. A dietary risk matrix was developed to illustrate how dietary advice can be given based on current intake.

Conclusion: Many associations between macronutrient intake and health outcomes are non-linear. Thus dietary advice could be tailored to current intake. Dietary guidelines on macronutrients (eg, carbohydrate) should also take account of differential associations of its components (eg, sugar and starch).

Fig 1

Association between percentage energy intake from macronutrients and all cause mortality. Analyses adjusted for age, sex, deprivation index, ethnicity, smoking status, height, body mass index categories, systolic blood pressure, baseline diabetes, mental health disorders, total physical activity, daily alcohol intake, and total energy intake. Components of macronutrients (eg, sugar, starch, and fibre) were mutually adjusted. Shaded areas represent 95% confidence intervals

Fig 2

Association between percentage energy from macronutrients and incidence of cardiovascular disease (CVD). Analyses were adjusted for age, sex, deprivation index, ethnicity, smoking status, height, body mass index categories, systolic blood pressure, baseline diabetes, mental health disorders, total physical activity, daily alcohol intake, and total energy intake. Components of macronutrients (eg, sugar, starch, and fibre) were mutually adjusted. Shaded areas represent 95% confidence intervals

Fig 3

Multivariable isocaloric analysis on replacing sugar intake with starch, monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), saturated fatty acids (SFA), and protein. Outcomes were all cause mortality (left panel) and incident cardiovascular disease (CVD) (right panel). Curves represent hazard ratios conditional on current intake of the replacement macronutrient. For example, for a person having 10% of energy from protein, replacing 5% of energy from fat by protein is associated with lower risk of all cause mortality. Macronutrients shown were mutually adjusted. Additionally, analyses were adjusted for age, sex, deprivation index, ethnicity, smoking status, height, body mass index categories, systolic blood pressure, baseline diabetes, mental health disorders, total physical activity, daily alcohol and fibre intake, and total energy intake. Shaded areas represent 95% confidence intervals

Fig 4

Multivariable isocaloric analysis on replacing intake of saturated fatty acids (SFA) with sugar, starch, monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), and protein. Outcomes were all cause mortality and incident cardiovascular disease (CVD) Curves represent hazard ratios conditional on current intake of the replacement macronutrient. For example, for a person having 10% of energy from protein, replacing 5% of energy from fat by protein is associated with lower risk of all cause mortality. Macronutrients shown were mutually adjusted. Additionally, analyses were adjusted for age, sex, deprivation index, ethnicity, smoking status, height, body mass index categories, systolic blood pressure, baseline diabetes, mental health disorders, total physical activity, daily alcohol and fibre intake, and total energy intake. Shaded areas represent 95% confidence intervals