Association of changes in red meat consumption with total and cause specific mortality among US women and men: two prospective cohort studies

Abstract

Objective: To evaluate the association of changes in red meat consumption with total and cause specific mortality in women and men.

Design: Two prospective cohort studies with repeated measures of diet and lifestyle factors.

Setting: Nurses' Health Study and the Health Professionals Follow-up Study, United States.

Participants: 53 553 women and 27 916 men without cardiovascular disease or cancer at baseline.

Main outcome measure: Death confirmed by state vital statistics records, the national death index, or reported by families and the postal system.

Results: 14 019 deaths occurred during 1.2 million person years of follow-up. Increases in red meat consumption over eight years were associated with a higher mortality risk in the subsequent eight years among women and men (both P for trend<0.05, P for heterogeneity=0.97). An increase in total red meat consumption of at least half a serving per day was associated with a 10% higher mortality risk (pooled hazard ratio 1.10, 95% confidence interval 1.04 to 1.17). For processed and unprocessed red meat consumption, an increase of at least half a serving per day was associated with a 13% higher mortality risk (1.13, 1.04 to 1.23) and a 9% higher mortality risk (1.09, 1.02 to 1.17), respectively. A decrease in consumption of processed or unprocessed red meat of at least half a serving per day was not associated with mortality risk. The association between increased red meat consumption and mortality risk was consistent across subgroups defined by age, physical activity, dietary quality, smoking status, or alcohol consumption.

Conclusion: Increases in red meat consumption, especially processed meat, were associated with higher overall mortality rates.

Fig 1

Hazard ratios (95% confidence intervals) for all cause mortality associated with an increase in red meat consumption of one serving per day over eight years according to characteristics of participants. Cox proportional hazards models were adjusted for initial age (years); race (white v other); family history of myocardial infarction, diabetes, or cancer (yes v no); initial aspirin use (yes v no) and multivitamin use (yes v no); initial consumption of red meat (in fifths); body mass index categories (<23, 23-24.9, 25-29.9, 30-34.9, and ≥35); menopausal status and hormone therapy use in women (premenopausal, postmenopausal and hormone therapy never user, postmenopausal and hormone therapy current user, postmenopausal and hormone therapy past user, or missing indicator); simultaneous changes in smoking status (never to never, never to current, former to former, former to current, current to former, current to current, or missing indicator); initial and simultaneous changes in physical activity, alcohol intake, total energy intake, and other main food groups, including vegetables, fruits, whole grains, and sugar-sweetened beverages (all in fifths). P for interaction was calculated using the likelihood ratio test. The cut-off point of physical activity was defined as 150 min/week at a moderate level or at least 75 min/week at a vigorous level (equivalent to at least nine MET hours/week) as recommended. Moderate alcohol consumption was defined as equivalent to 14 g/day in women and 28 g/day in men; alternative healthy eating index higher or equal to versus lower than median in each cohort. MET=metabolic equivalent of task