The number of people affected by diabetes globally is rapidly increasing with estimates already surpassing 425 million in 2017 and projected to reach 629 million in 2045 (1). A few small studies have found that vegetarians might have a lower risk of diabetes than non-vegetarians but they have been limited by small numbers of cases (Reference Snowdon and Phillips2, Reference Chiu, Pan and Lin3, Reference Tonstad, Stewart and Oda4, Reference Vang, Singh and Lee5). Therefore, we examined the association between vegetarianism and diabetes risk in a large, prospective study of British adults
The analysed cohort included participants from the European Prospective Investigation into Cancer (EPIC)-Oxford study who were diabetes free at recruitment (1993-1999), with available dietary intake data at baseline, and linked hospital admissions and death data for diabetes over follow-up (1994-2016) (n = 45,314)(Reference Crowe, Appleby and Travis6). Participants were categorized as regular meat eaters (>50 grams per day: n = 15,181); low meat eaters (<50 grams of meat per day: n = 7,615); fish eaters (ate no meat but consumed fish: n = 7,092); and vegetarians and vegans (ate no meat or fish: n = 15,426).We used multivariable Cox proportional hazards models to assess associations between diet and risk of diabetes.
Over a mean of 17.6 years of follow-up, 1224 incident cases of diabetes were recorded (11 of which were first noted at death). Compared with regular meat eaters, the low meat eaters, fish eaters, and vegetarians and vegans were less likely to develop diabetes (hazard ratio (HR) = 0.63, 95 % confidence interval (CI) 0.54-0.75; HR = 0.47, 95 % CI 0.38-0.59; and HR = 0.63, 95 % CI 0.54-0.74, respectively). These associations were substantially attenuated after adjusting for body mass index (BMI) (low meat eaters: HR = 0.78, 95 % CI 0.66-0.92; fish eaters: HR = 0.64, 95 % CI 0.51-0.80; and vegetarians and vegans: HR = 0.89, 95 % CI 0.76-1.05) (Table 1).
Model 1: Analysis stratified by sex, method of recruitment, region of residence and adjusted for age, education, Townsend deprivation index, ethnicity, smoking, alcohol intake, and physical activity. Model 2: Analysis further adjusted for BMI. 1 Represents significant heterogeneity in risk between diet groups based on likelihood-ratio test statistics.
We found that consuming a low or meat-free diet was associated with a lower risk of diabetes, and that this was at least partly attributable to these groups having a lower BMI than regular meat eaters. Our findings suggest that consuming low-meat or vegetarian diets may have a role in controlling the growing diabetes epidemic.
This work is supported by Wellcome Trust Our Planet Our Health (Livestock, Environment and People, LEAP 205212/Z/16/Z).