The role of income level for the relationship between body mass index and health related quality of life in Northern Sweden
Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
Background: Overweight and obesity are rising as major public health problems. There is evidence that Body Mass Index (BMI) is associated with health-related quality of life (HRQoL), where non-normal weight group (underweight, overweight, and obesity) generally have a lower HRQoL compared to normal weight group. However, there is little known whether the relationship between BMI and HRQoL is varying by income level.
Objective: Investigate the relationship between BMI and HRQoL in Northern Sweden, and whether or not income level moderates the relationship.
Methods: A cross-sectional study from Sweden‘s national public health survey ―Health on equal terms‖ 2014 representing sample aged 20-84 years old with a response rate of 50%. A total of 20082 individuals were included for analysis after excluding missing values. BMI and HRQoL (measured by EQ-5D) were self-reported and income measured as individual disposable income in 2012. Multiple linear regressions were performed with HRQoL score as the outcome, BMI as an independent variable, income as third variable and covariates (potential confounders). Multiplicative interaction between BMI group and income level was also presented in order to test whether income had a role as an effect modifier in the relationship between BMI and HRQoL. Sensitivity analyses were also performed in order to check the sensitivity of the main results.
Results: Underweight, overweight, and obesity in average had significantly lower HRQoL compared to normal weight group which accounted for 0.042 units lower in the underweight group, 0.022 units lower in the overweight group, and 0.08 units lower in the obese group compared to normal weight group. The relationship between BMI and HRQoL was significantly varied by tertile of income. Therefore, income was a presence as an effect modifier in the relationship between BMI and HRQoL and results in the greater of decreasing units HRQoL for the obese group in the lower income level compared to the obese group in the higher level of income. The sensitivity analysis portrayed the same inferences with the main analysis and supports the evidence that there was a relationship between BMI and HRQoL and the relationship varied by income level.
Conclusion: The impact of BMI on HRQoL is greater among low-income level. Thus, income has a role as an effect modifier in the relationship between BMI and HRQoL. Efforts to increase HRQoL in the populations should not only focus on reducing the prevalence of overweight and obesity but also pay attention to the existence of the different impact of being overweight and obese in different income level.
Place, publisher, year, edition, pages
2016. , 33 p.
Centre for Public Health Report Series, ISSN 1651-341x ; 2016:16
BMI, overweight, obesity, HRQoL, EQ-5D, income, SES, effect modifier, effect modification
Public Health, Global Health, Social Medicine and Epidemiology
IdentifiersURN: urn:nbn:se:umu:diva-131509OAI: oai:DiVA.org:umu-131509DiVA: diva2:1074714
Hälsa på lika vilkor 2014- Västerbotten, Norrbotten, Jämtland och Västernorrland
Master's Programme in Public Health
2016-05-23, Umeå Universitet, Umeå, 08:50 (English)
Gustafsson, Per, Senior lecturer, associate
San Sebastian, Miguel, Professor