Independent and combined effects of physical activity and body mass index on the development of Type 2 Diabetes - a meta-analysis of 9 prospective cohort studies.

BACKGROUND: The aim of this harmonized meta-analysis was to examine the independent and combined effects of physical activity and BMI on the incidence of type 2 diabetes. METHODS: Our systematic literature review in 2011 identified 127 potentially relevant prospective studies of which 9 fulfilled the inclusion criteria (total N = 117,878, 56.2 % female, mean age = 50.0 years, range = 25-65 years). Measures of baseline physical activity (low, intermediate, high), BMI-category [BMI < 18.4 (underweight), 18.5-24.9 (normal weight), 25.0-29.9 (overweight), 30+ (obese)] and incident type 2 diabetes were harmonized across studies. The associations between physical activity, BMI and incident type 2 diabetes were analyzed using Cox regression with a standardized analysis protocol including adjustments for age, gender, educational level, and smoking. Hazard ratios from individual studies were combined in a random-effects meta-analysis. RESULTS: Mean follow-up time was 9.1 years. A total of 11,237 incident type 2 diabetes cases were recorded. In mutually adjusted models, being overweight or obese (compared with normal weight) and having low physical activity (compared with high physical activity) were associated with an increased risk of incident type 2 diabetes (hazard ratios 2.33, 95 % CI 1.95-2.78; 6.10, 95 % CI: 4.63-8.04, and 1.23, 95 % CI: 1.09-1.39, respectively). Individuals who were both obese and had low physical activity had 7.4-fold (95 % CI 3.47-15.89) increased risk of type 2 diabetes compared with normal weight, high physically active participants. CONCLUSIONS: This harmonized meta-analysis shows the importance of maintaining a healthy weight and being physically active in diabetes prevention.

Psychological distress as a determinant of changes in body mass index over a period of 10years.

OBJECTIVE: To examine the longitudinal relationship between psychological distress and body mass index (BMI) changes over a period of five and ten years. METHOD: Data were used from the Dutch, prospective, population based Doetinchem Cohort study over the period 1995/1999 until 2005/2009 (N=5504). Psychological distress was assessed using the Mental Health Inventory (MHI-5). BMI (kg/m(2)) was calculated from measured body height and body weight. GEE analyses were used to examine the relationship between psychological distress at baseline and BMI change, and the development of overweight over five years. Linear and logistic regression analyses were used to examine these relations over ten years. RESULTS: Psychological distress predicted an extra overall increase in BMI of 0.14kg/m(2) (95% CI 0.03-0.25) over five years and an increase of 0.18kg/m(2) (95% CI 0.01-0.35) over ten years, when comparing psychologically distressed participants to psychologically healthy participants. This was especially the case among persons with normal weight (five years; B=0.26kg/m(2), 95% CI=0.12-0.40/ten years; B=0.32kg/m(2) 95% CI=0.11-0.53) and moderate overweight (five years: B=0.18kg/m(2), 95% CI=0.02-0.35) at baseline. Psychological distress did not predict the development of overweight five and ten years later. CONCLUSION: The results in this study indicated that psychological distress predicted an increased risk in gaining weight, but did not result in an increased risk for developing overweight.

The effectiveness of interventions for ageing workers on (early) retirement, work ability and productivity: a systematic review.

PURPOSE: To systematically summarise the literature on the effects of interventions for ageing workers that address work-related measures of sustainable employability, i.e. (early) retirement, work ability and work productivity. METHODS: A systematic review was performed by searching five electronic databases for relevant studies published between January 1992 and February 2014. Randomised controlled trials (RCTs) and quasi-experimental intervention studies were included. The study population included workers aged ≥40 years, and the measured outcomes were positive indicators of labour force participation, i.e. (early) retirement, work ability and work productivity. The methodological quality of each included study was assessed, and best-evidence synthesis was applied to draw conclusions about the evidence for the effectiveness of each outcome. RESULTS: Four studies met the inclusion criteria. The interventions were diverse and ranged from individual (e.g. exercise) programmes to workplace programmes. Limited evidence for a favourable effect on early retirement was found. Insufficient evidence was found for the remaining outcomes, i.e. work ability and productivity, due to a lack of high-quality studies and consistent findings. CONCLUSIONS: Insufficient and limited evidence is available for a favourable effect of interventions to promote work-related components of sustainable employability in ageing workers. This is due to a scarcity of RCTs and inconsistent findings between the limited number of studies. Additional intervention studies are needed to support evidence-based decision making to prolong a healthy and productive working life for ageing workers.