Abstract P518: Prospective Study of Skipping Meals to Lose Weight as a Predictor of Incident Type 2 Diabetes and Coronary Heart Disease: The Canadian 1995 Nova Scotia Health Survey
Authors: Carew Allie S , Mekary Rania , Mukamal Kenneth J , Rimm Eric , Ivey Kerry L , Kirkland Susan , Urquhart Robin , Theou Olga , Blanchard Chris , Parkash Ratika , Siddiqi Ferhan , Bennett Mark , Hu Frank B , Cahill Leah E 
Published: March 2020

Introduction:
Skipping meals is an increasingly common practice to lose weight among North American adults of all bodyweights. However, due to a lack of long-term studies, the long-term effect of skipping meals to lose weight on cardiometabolic health outcomes such as a diagnosis of type 2 diabetes mellitus (T2DM) or incident coronary heart disease (CHD) remains unknown, although previous short-term studies of skipping meals and risk factors for T2DM and CHD have suggested plausible biological pathways for a relationship to exist in either direction, protective or harmful.

Hypothesis:
We assessed the hypotheses that skipping meals to lose weight was associated with long-term risk of incident T2DM and CHD in the Canadian 1995 Nova Scotia Health Survey (NSHS95), and that these associations were influenced by cardiometabolic risk factors.

Methods:
Skipping meals to lose weight was assessed via questionnaire in a cohort of 2,898 adults in the NSHS95 and was linked to population-based health care administrative databases to determine incidence of T2DM and/or CHD in the following 23 years. Multivariable Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for T2DM and CHD.

Results:
During 23 years of follow-up, 430 incident cases of T2DM and 632 incident cases of CHD were diagnosed. Compared to participants who did not skip meals to lose weight, those who did skip meals to lose weight (2.7%) had an 87% higher risk of T2DM (multivariable-adjusted HR=1.87, 95% CI: 1.11-3.17). This association was no longer present after adjustment for baseline body mass index (BMI) (HR=1.42, 0.83-2.42). After stratification by BMI, skipping meals was associated with T2DM among participants who had BMI <25 kg/m
2
(n=1,030; HR=4.42, 1.01-19.30) but not among participants with BMIs of 25-29.9 kg/m
2
(n=1,123; HR=1.07, 0.39-2.96) or 30+ kg/m
2
(n=586; HR=1.21, 0.61-2.39). The multivariable-adjusted (including BMI) association was also present within participants with elevated cholesterol (n=1,450; HR=1.88, 1.00-3.53) and high blood pressure (n=1,363; HR=2.07, 1.11-3.85), but not among those without. No significant association was observed between skipping meals to lose weight and CHD risk before (HR=1.14, 0.67-1.96) or after adjustment for BMI (HR=1.05, 0.61-1.81), or within subgroups.

Conclusion:
These findings suggest that skipping meals to lose weight may be a predictive modifiable risk factor for developing T2DM over time, especially among people with a BMI <25 kg/m
2
, potentially working in connection or iteration with other T2DM risk factors. With the growing number of popular diets that include skipping meals, future studies are warranted to understand perturbations of potential metabolic consequences.