Background: Overweight and obese persons are at risk of a number of medical conditions which can lead to further morbidity and mortality. The primary objective of this study is to provide an estimate of the incidence of each co-morbidity related to obesity and overweight using a meta-analysis.Methods: A literature search for the twenty co-morbidities identified in a preliminary search was conducted in Medline and Embase (Jan 2007). Studies meeting the inclusion criteria (prospective cohort studies of sufficient size reporting risk estimate based on the incidence of disease) were extracted. Study-specific unadjusted relative risks (RRs) on the log scale comparing overweight with normal and obese with normal were weighted by the inverse of their corresponding variances to obtain a pooled RR with 95% confidence intervals (CI).Results: A total of 89 relevant studies were identified. The review found evidence for 18 co-morbidities which met the inclusion criteria. The meta-analysis determined statistically significant associations for overweight with the incidence of type II diabetes, all cancers except esophageal (female), pancreatic and prostate cancer, all cardiovascular diseases (except congestive heart failure), asthma, gallbladder disease, osteoarthritis and chronic back pain. We noted the strongest association between overweight defined by body mass index (BMI) and the incidence of type II diabetes in females (RR = 3.92 (95% CI: 3.10–4.97)). Statistically significant associations with obesity were found with the incidence of type II diabetes, all cancers except esophageal and prostate cancer, all cardiovascular diseases, asthma, gallbladder disease, osteoarthritis and chronic back pain. Obesity defined by BMI was also most strongly associated with the incidence of type II diabetes in females (12.41 (9.03–17.06)).Conclusion: Both overweight and obesity are associated with the incidence of multiple co-morbidities including type II diabetes, cancer and cardiovascular diseases. Maintenance of a healthy weight could be important in the prevention of the large disease burden in the future. Further studies are needed to explore the biological mechanisms that link overweight and obesity with these co-morbidities.

Introduction: The Work Productivity and Activity Impairment (WPAI) questionnaire is a well validated instrument to measure impairments in work and activities. However, its validation among patients with rheumatoid arthritis (RA) has not been well established. The present study's purpose is to evaluate the construct validity of the WPAI-general health version among RA patients and its ability to differentiate between RA patients with varying health status. Methods: Patients who were enrolled in the Early Rheumatoid Arthritis Network cohort and were employed at their most recent follow-up were recruited into this sub-study. A questionnaire battery incorporating the WPAI was administered along with a number of health outcomes including the Multidimensional Health Assessment Questionnaire, fatigue and patient assessment of disease activity. The construct validity of the WPAI was tested by the correlations between the WPAI and the health outcomes and other measures of productivity. Student's t tests were used to identify whether the WPAI outcomes differed between the two levels of heath status based on the median of health outcomes. Results: A total of 150 patients completed the WPAI questionnaire. The average age was 52 years old and the disease duration was 37.5 months since the first rheumatology visit. Of the 137 patients who were working for pay, 26 reported missing work in the past week due to their health problem, accounting for 45.5% of their working time (absenteeism). While 123 patients were working, 24% of their work was impaired due to their health problem (presenteeism). In addition, 33% of the patients' regular daily activities (activity impairment) had been prevented due to their health problems. There were moderate correlations between the WPAI absenteeism and function, pain, fatigue, and disease severity (r = 0.34 to 0.39). The WPAI presenteeism and activity impairment were strongly correlated with the health outcomes (0.67 to 0.77). Patients with more severe disease status (for example, low/high functional disability by median) had significantly higher absenteeism (4%/15%), presenteeism (15%/39%), and activity impairment (19%/53%) than those with less severe disease status. Conclusions: The WPAI is a valid questionnaire for assessing impairments in paid work and activities in RA patients and for measuring the relative differences between RA patients with different health status.

Worker productivity is a combination of time off work (absenteeism) due to an illness and time at work but with reduced levels of productivity while at work (also known as presenteeism). Both can be gathered with a focus on application as a cost indicator and/or as an outcome state for intervention studies. We review the OMERACT worker productivity groups’ progress in evaluating measures of worker productivity for use in arthritis using the OMERACT filter. Attendees at OMERACT 9 strongly endorsed the importance of work as an outcome in arthritis. Consensus was reached (94% endorsement) for fielding a broader array of indicators of absenteeism. Twenty-one measures of at-work productivity loss, ranging from single item indicators to multidimensional scales, were reviewed for measurement properties. No set of at-work productivity measures was endorsed because of variability in the concepts captured, and the need for a better framework for the measurement of worker productivity that also incorporates contextual issues such as job demands and other paid and unpaid life responsibilities. Progress has been made in this area, revealing an ambivalent set of results that directed us back to the need to further define and then contextualize the measurement of worker productivity.