Association between body mass index and health-related quality of life, and the impact of self-reported long-term conditions - cross-sectional study from the south Yorkshire cohort dataset.

BACKGROUND: We sought to quantify the relationship between body mass index (BMI) and health-related quality (HRQoL) of life, as measured by the EQ-5D, whilst controlling for potential confounders. In addition, we hypothesised that certain long-term conditions (LTCs), for which being overweight or obese is a known risk factor, may mediate the association between BMI and HRQoL. Hence the aim of our study was to explore the association between BMI and HRQoL, first controlling for confounders and then exploring the potential impact of LTCs.
METHODS: We used baseline data from the South Yorkshire Cohort, a cross-sectional observational study which uses a cohort multiple randomised controlled trial design. For each EQ-5D health dimension we used logistic regression to model the probability of responding as having a problem for each of the five health dimensions. All continuous variables were modelled using fractional polynomials. We examined the impact on the coefficients for BMI of removing LTCs from our model. We considered the self-reported LTCs: diabetes, heart disease, stroke, cancer, osteoarthritis, breathing problems and high blood pressure.
RESULTS: The dataset used in our analysis had data for 19,460 individuals, who had a mean EQ-5D score of 0.81 and a mean BMI of 26.3 kg/m². For each dimension, BMI and all of the LTCs were significant predictors. For overweight or obese individuals (BMI ≥ 25 kg/m²), each unit increase in BMI was associated with approximately a 3% increase in the odds of reporting a problem for the anxiety/depression dimension, a 8% increase for the mobility dimension, and approximately 6% for the remaining dimension s. Diabetes, heart disease, osteoarthritis and high blood pressure were identified as being potentially mediating variables for all of the dimensions.
CONCLUSIONS: Compared to those of a normal weight (18.5 < BMI < 25 kg/m²), overweight and obese individuals had a reduced HRQoL, with each unit increase in BMI associated with approximately a 6% increase in the odds of reporting a problem on any of the EQ-5D health dimensions. There was evidence to suggest that diabetes, heart disease, osteoarthritis and high blood pressure may mediate the association between being overweight and HRQoL.

Methods

We employed our newly adopted SVM method in the continuous measurement of the cortical width of the mandible on dental panoramic radiographs to identify osteoporosis. We compared the diagnostic performances between this newly developed method and our trimmed mean method in identifying women with low BMD at the lumbar spine and the femoral neck in 100 postmenopausal women ([greater than or equal to]50 years), of whom 60 to the training and 40 to its testing with no previous record of osteoporosis. Cortical width below the mental foramen of the mandible on dental panoramic radiographs was measured continuously with CAD system by enhancing the original image of the X-ray, determining cortical boundaries, evaluating all the distances among upper and lower boundaries and finally discriminating by radial basis function - support vector machine method.

Results and Discussion

The sensitivity and specificity of the cortical measurements of the lumbar spine were 90.9% (95% confidence interval shown in parentheses) (85.3-96.5) and 83.8% (76.6-91.0), respectively and 90.0% (84.1-95.9) and 69.1% (60.1-78.6), respectively with femoral neck BMD. In addition, the sensitivity and specificity for the combination of data of both the lumbar spine and femoral neck for identifying women with low BMD were 90.6% (92.0-100) and 80.9% (71.0-86.9), respectively. We assessed that the diagnosis and classification of women using support vector machine employing the average and variance of the continuous measurements provide excellent discrimination ability in comparison with the estimation of cortical width using the trimmed mean method. Conclusion: Results showed that our newly developed CAD system with SVM method improves the overall performance of the identification of high risk group of osteoporotic patients. Overall, most promising results in terms of best overall response rate (BORR) were obtained with 10 mg/kg of ipilimumab, every 3 weeks for a total of 4 doses (induction phase) followed by maintenance period in which ipilimumab was administrated every 12 weeks (maintenance phase). This was the reason for the choice of such a schedule for the front line phase 3 study. The most common treatment-related adverse events (AEs) associated with the use of ipilimumab were immune-related and specific algorithms have been subsequently developed, showing that early recognition and correct therapeutic approach with steroid therapy make most of these AEs manageable and reversible

Pre-publication history

The pre-publication history for this paper can be accessed here:

http://www.biomedcentral.com/1471-2458/13/1009/prepub