Past food habit change is related to obesity, lifestyle and socio-economic factors in the Malmo Diet and Cancer Cohort.

Summary, in English

Objectives: To examine if obesity status and socio-economic and lifestyle factors are

associated with self-reported past food habit change, and also whether the level of

obesity depends on the reason for change.

Design: Cross-sectional analysis within the Malmo Diet and Cancer (MDC) study using

data from the baseline examination and the extensive socio-economic and lifestyle

questionnaire including questions of past food habit change. The risk of having

changed food habits in the past was examined using logistic regression. Mean

differences in obesity status across categories of reasons for past food habit change

were examined using analysis of variance.

Setting: Malmo¨, the third largest city in Sweden.

Subjects: A sub-sample (15 282 women and 9867 men) from the MDC cohort recruited

from 1992 to 1996.

Results: Individuals with body mass index (BMI) .30 kgm22 had an increased risk of

having reported past food habit change compared with individuals with BMI

,25 kgm22 (odds ratio (OR) ¼ 1.63, 95% confidence interval (CI) ¼ 1.48–1.83 for

women; OR ¼ 1.53, 95% CI ¼ 1.32–1.76 for men). The highest level of obesity was

observed among individuals who had changed their diet due to reasons related to the

metabolic syndrome. Changers were more likely to be highly educated and to live

alone, be retired, ex-smokers and non-drinkers at baseline.

Conclusions: Because past food habit change is related to obesity and other lifestyle

and socio-economic factors, a complex confounding situation may exist that could

seriously influence observed relationships between diet and disease. Studies need to

collect information on past food habit change and take this information into account

in the analysis and when interpreting study outcomes.