The Adventist Health Study-2 (AHS-2) is a cohort study following the health of a group with a high prevalence of vegetarians and vegans. Prior descriptions of this cohort have demonstrated that BMI was lowest in vegans (23.6) and highest among non-vegetarians (28.8). However, the change in BMI based on dietary patterns has not previously been explored.
Subjects consist of the AHS-2 cohort in the United States and Canada. Change in BMI/year, was computed using self-reported baseline height and the differences in self-reported weight and age between the surveys. The dietary patterns of participants were determined using a quantitative food frequency questionnaire and validated using 24-hour dietary recalls. Data were analyzed with SAS 9.4 by multi-linear regression analysis with variables included a priori.
We analyzed 49,164 participants with a mean +/- SD follow-up time of 10.8 +/- 1.9 years. The BMI change per year for the entire group had a mean and SD of 0.01 +/- 0.27. The dietary patterns used included vegan, lacto-ovo-vegetarian, pesco-vegetarian, semi-vegetarian, and 2 non-vegetarian groups. The initial BMI for each of the described dietary patterns ranged from 23.7 +/- 4.5 to 29.0 +/- 6.2 across the 6 dietary patterns. In comparison to the vegan group, there was a relative increase in BMI per year across all dietary groups. The non-vegetarian group with the highest amount of animal products consumed experienced the largest increase in BMI per year (0.017), while the lacto-vegetarians experienced the smallest increase (0.041).
Dietary patterns with a higher amount of animal products may lead to increased BMIs over time.