The health consequences of obesity history and weight fluctuations in adulthood.

Background: The prevalence of Canadians living with obesity has increased over the past four decades. Disease and mortality risk increase as the number of years lived with obesity increases.

Methods: This study used self-reported weight history and health data collected from 2007 to 2011 via the Canadian Health Measures Survey (n = 5,761) to examine whether increased exposure to obesity during adulthood increases the odds of having poor health outcomes.

Results: The percentage of respondents with an obesity-related chronic condition was lower among those who did not have obesity at the time of survey or report having obesity in the past (50.6%) compared with those who did not have obesity at the time of the survey but did in the past (65.9%) or who had obesity at the time of the survey and in the past (71.1%). Relative to never having obesity, having obesity in the past but not at present or having obesity in the past and at present were associated with increased odds of having a range of chronic conditions. The highest odds were observed for type 2 diabetes (odd ratio (OR) = 3.26, 95% confidence interval (CI): 2.40 to 4.43 and OR = 5.36, 95% CI: 3.88 to 7.41), hypertension (OR = 2.41, 95% CI: 1.69 to 3.44 and OR = 3.76, 95% CI: 2.84 to 4.97), and poor or fair self-rated general health (OR = 2.04, 95% CI: 1.51 to 2.76 and OR = 2.68, 95% CI: 2.11 to 3.40).

Interpretation: Having had obesity in the past, regardless of current obesity status, was associated with increased odds of poor health outcomes. Obesity history information should be considered when estimating the population burden of obesity.