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.

Influence of calendar period on the association between BMI and coronary heart disease: a meta-analysis of 31 cohorts.

OBJECTIVE: The association between obesity and coronary heart disease (CHD) may have changed over time, for example due to improved pharmacological treatment of CHD risk factors. This meta-analysis of 31 prospective cohort studies explores the influence of calendar period on CHD risk associated with body mass index (BMI). DESIGN AND METHODS: The relative risks (RRs) of CHD for a five-BMI-unit increment and BMI categories were pooled by means of random effects models. Meta-regression analysis was used to examine the influence of calendar period (>1985 v ≤1985) in univariate and multivariate analyses (including mean population age as a covariate). RESULTS: The age, sex, and smoking adjusted RR (95% confidence intervals) of CHD for a five-BMI-unit increment was 1.28(1.22:1.34). For underweight, overweight and obesity, the RRs (compared to normal weight) were 1.11(0.91:1.36), 1.31(1.22:1.41), and 1.78(1.55:2.04), respectively. The univariate analysis indicated 31% (95%CI: -56:0) lower RR of CHD associated with a five-BMI-unit increment and a 51% (95%CI: -78: -14)) lower RR associated with obesity in studies starting after 1985 (n = 15 and 10, respectively) compared to studies starting in or before 1985 (n = 16 and 10). However, in the multivariate analysis, only mean population age was independently associated with the RRs for a five-BMI-unit increment and obesity (-29(95%CI: -55: -5)) and -31(95%CI: -66:3), respectively) per 10-year increment in mean age). CONCLUSION: This study provides no consistent evidence for a difference in the association between BMI and CHD by calendar period. The mean population age seems to be the most important factor that modifies the association between the risk of CHD and BMI, in which the RR decreases with increasing age.

Associations between changes in anthropometric measures and mortality in old age: a role for mid-upper arm circumference?

OBJECTIVES: In elderly individuals, little is known about changes in different anthropometric measures with respect to mortality. We examined the association between changes in eight anthropometric measures and mortality in an elderly population. DESIGN: Longitudinal study including baseline measurements in 1988-1990 and repeated measures in 1993. SETTING: European towns. PARTICIPANTS: A total of 1061 older adults born in 1913-1918 from the Survey in Europe on Nutrition and the Elderly, A Concerted Action study were included in this study. MEASUREMENTS: Weight, body mass index, waist circumference, waist to hip ratio, waist to height ratio, mid-upper arm circumference (MUAC), triceps skinfold thickness, and corrected arm muscle area were taken during both measurements. RESULTS: A Cox regression model was used to examine the association between anthropometric changes (divided into quintiles, smallest change = reference category) and all-cause and cardiovascular disease mortality over approximately 6 years of follow-up, adjusted for baseline measurement of application, age, sex, smoking, education, physical activity, and major chronic diseases. A decrease in weight (≥3.2 kg), waist circumference (≥3.1 cm), and MUAC (≥1.6 cm and 0.6-1.6 cm) were (near) significantly associated with an all-cause mortality risk of 1.48 (95% CI: 0.99-2.20), 1.52 (95% CI: 1.01-2.31), 1.81 (95% CI: 1.17-2.79), and 1.66 (95% CI: 1.10-2.49), respectively. Also for MUAC, an increase (≥1.3 cm) was significantly associated with an increased all-cause and cardiovascular disease mortality risk [hazard ratio, 1.52 (95% CI: 1.00-2.31) and 1.94 (95% CI: 1.00-3.75), respectively]. CONCLUSION: Associations were observed for decreases in only 3 of 8 anthropometric measures and all-cause mortality. Decreases in MUAC had the strongest association with mortality and was the only measure in which an increase also was associated with mortality. This suggests a role for MUAC in the prediction of mortality in elderly individuals.

Maintenance of lifestyle changes: 3-year results of the Groningen Overweight and Lifestyle study.

OBJECTIVE: This study aims to evaluate the three-year effect of lifestyle counseling by a nurse practitioner (NP) on physical activity (PA) and dietary intake compared with usual care by a general practitioner (GP). METHODS: At baseline, subjects were randomly allocated to the NP group (n = 225) or to the GP group (n = 232). The NP group received a low-intensive lifestyle intervention for three years by the NP and the GP group received one consultation by the GP and thereafter usual care. PA and dietary intake were assessed with questionnaires at baseline, 1 year follow-up and 3 year follow-up. RESULTS: After three years, leisure-time activity increased and favorable improvements towards a healthy diet were made for both groups. These three-year changes in PA and diet did not differ significantly between groups. Changes in PA and dietary habits after one year were practically maintained after 3 years, because only small relapses were found. CONCLUSION: After three years, subjects were more physically active and had a healthier diet compared to baseline. Lifestyle counseling by NP resulted in similar lifestyle changes compared to GP consultation. PRACTICE IMPLICATIONS: NPs could also advice patients at cardiovascular risk by lifestyle counseling, to possibly reduce GP barriers.

Body mass index and cognitive ability of young children.

OBJECTIVE: This study prospectively assessed the association between body mass index (BMI) and cognitive ability of young children, while accounting for confounding factors. METHODS: The study included 236 children born between 1990 and 1994 participating in a Dutch birth cohort study. Anthropometric data of the children at birth, 4, and 7 years of age were collected from growth records or measured at the Academic Hospital of Maastricht. The Kaufman Assessment Battery for Children (K-ABC) was used to assess cognitive ability at 7 years of age. The association between BMI and cognitive ability was investigated using univariate and multivariate linear regression analyses, including various covariates. RESULTS: Although the results suggest that cognitive ability at 7 years of age decreased with increasing BMI at 4 years and 7 years of age, this association was not significant in any performed analysis. Multivariate analyses showed that maternal intelligence was strongly associated with all scales of the K-ABC as a significant covariate. Adjusting analyses for physical fitness of the child, maternal education, maternal pre-pregnancy BMI, maternal smoking during pregnancy, and birth weight did not change the results. CONCLUSION: This study found no evidence for an association between BMI and cognitive ability of school-aged children.

Changes in lifestyle habits after counselling by nurse practitioners: 1-year results of the Groningen Overweight and Lifestyle study.

OBJECTIVES: The Groningen Overweight and Lifestyle (GOAL) study primarily aims at preventing weight gain by nurse practitioners (NP) guided by a standardized computerized software program. Since favourable changes in physical activity (PA) and diet may improve health independently of weight (loss), insight into effects on lifestyle habits is essential. We examined the 1-year effects of lifestyle counselling by NP on PA and diet, compared with usual care from the general practitioner (GP-UC). DESIGN: A randomized controlled trial. SETTING: Eleven general practice locations in the Netherlands. SUBJECTS: A total of 341 GOAL participants with overweight or obesity and either hypertension or dyslipidaemia, or both, who completed an FFQ and Short Questionnaire to Assess Health-Enhancing Physical Activity (SQUASH) at baseline and after 1 year. RESULTS: After 1 year, the NP group spent 33 min/week more on walking compared with the GP-UC group who spent -5 min/week on walking (P = 0.05). No significant differences were found between the NP and GP-UC groups on the percentage of persons complying with the PA guidelines. In both groups, nutrient intake changed in a favourable direction and participants complied more often with dietary guidelines, but without overall difference between the NP and GP-UC groups. CONCLUSIONS: With the exception of an increase in walking (based on self-reported data) in the NP group, no intervention effects on PA and diet occurred. Positive changes in nutrient intake were seen in both groups.

Diet, Screen Time, Physical Activity, and Childhood Overweight in the General Population and in High Risk Subgroups: Prospective Analyses in the PIAMA Birth Cohort.

Objective. To prospectively identify behavioral risk factors for childhood overweight and to assess their relevance in high risk sub groups (children of mothers with overweight or low education). Methods. In the PIAMA birth cohort (n = 3963), questionnaire data were obtained at ages 5 and 7 on "screen time", walking or cycling to school, playing outside, sports club membership, fast food consumption, snack consumption and soft drink consumption. Weight and height were measured at age 8 years. Results. Screen time, but none of the other hypothesized behavioral factors, was associated with overweight (aOR 1.4 (CI: 1.2-1.6)). The adjusted population attributable risk fraction for screen time > 1 hr/day was 10% in the high risk and 17% in the low risk sub groups. Conclusion. Reduction of screen time to < 1 hr/day could result in a reduction of overweight prevalence in the order of 2 percentage points in both high and low risks sub groups.

The LIFESTYLE study: costs and effects of a structured lifestyle program in overweight and obese subfertile women to reduce the need for fertility treatment and improve reproductive outcome. A randomised controlled trial.

BACKGROUND: In the Netherlands, 30% of subfertile women are overweight or obese, and at present there is no agreement on fertility care for them. Data from observational and small intervention studies suggest that reduction of weight will increase the chances of conception, decrease pregnancy complications and improve perinatal outcome, but this has not been confirmed in randomised controlled trials. This study will assess the cost and effects of a six-months structured lifestyle program aiming at weight reduction followed by conventional fertility care (intervention group) as compared to conventional fertility care only (control group) in overweight and obese subfertile women. We hypothesize that the intervention will decrease the need for fertility treatment, diminish overweight-related pregnancy complications, and will improve perinatal outcome. METHODS/DESIGN: Multicenter randomised controlled trial in subfertile women (age 18-39 year) with a body mass index between 29 and 40 kg/m2. Exclusion criteria are azoospermia, use of donor semen, severe endometriosis, premature ovarian failure, endocrinopathies or pre-existent hypertensive disorders.In the intervention group the aim is a weight loss of at least 5% to10% in a six-month period, to be achieved by the combination of a diet, increase of physical activity and behavioural modification. After six months, in case no conception has been achieved, these patients will start fertility treatment according to the Dutch fertility guidelines. In the control group treatment will be started according to Dutch fertility guidelines, independently of the patient's weight. OUTCOME MEASURES AND ANALYSIS: The primary outcome measure is a healthy singleton born after at least 37 weeks of gestation after vaginal delivery. Secondary outcome parameters including pregnancy outcome and complications, percentage of women needing fertility treatment, clinical and ongoing pregnancy rates, body weight, quality of life and costs.Data will be analysed according to the intention to treat principle, and cost-effectiveness analysis will be performed to compare the costs and health effects in the intervention and control group. DISCUSSION: The trial will provide evidence for costs and effects of a lifestyle intervention aiming at weight reduction in overweight and obese subfertile women and will offer guidance to clinicians for the treatment of these patients. TRIAL REGISTRATION: Dutch Trial Register NTR1530.

Lifestyle counseling in hypertension-related visits--analysis of video-taped general practice visits.

BACKGROUND: The general practitioner (GP) can play an important role in promoting a healthy lifestyle, which is especially relevant in people with an elevated risk of cardiovascular diseases due to hypertension. Therefore, the aim of this study was to determine the frequency and content of lifestyle counseling about weight loss, nutrition, physical activity, and smoking by GPs in hypertension-related visits. A distinction was made between the assessment of lifestyle (gathering information or measuring weight or waist circumference) and giving lifestyle advice (giving a specific advice to change the patient's behavior or referring the patient to other sources of information or other health professionals). METHODS: For this study, we observed 212 video recordings of hypertension-related visits collected within the Second Dutch National Survey of General Practice in 2000/2001. RESULTS: The mean duration of visits was 9.8 minutes (range 2.5 to 30 minutes). In 40% of the visits lifestyle was discussed (n = 84), but in 81% of these visits this discussion lasted shorter than a quarter of the visit. An assessment of lifestyle was made in 77 visits (36%), most commonly regarding body weight and nutrition. In most cases the patient initiated the discussion about nutrition and physical activity, whereas the assessment of weight and smoking status was mostly initiated by the GP. In 35 visits (17%) the GP gave lifestyle advice, but in only one fifth of these visits the patient's motivation or perceived barriers for changing behavior were assessed. Supporting factors were not discussed at all. CONCLUSION: In 40% of the hypertension-related visits lifestyle topics were discussed. However, both the frequency and quality of lifestyle advice can be improved.

Association of overweight with increased risk of coronary heart disease partly independent of blood pressure and cholesterol levels: a meta-analysis of 21 cohort studies including more than 300 000 persons.

BACKGROUND: The extent to which moderate overweight (body mass index [BMI], 25.0-29.9 [calculated as weight in kilograms divided by height in meters squared]) and obesity (BMI, >/= 30.0) are associated with increased risk of coronary heart disease (CHD) through adverse effects on blood pressure and cholesterol levels is unclear, as is the risk of CHD that remains after these mediating effects are considered. METHODS: Relative risks (RRs) of CHD associated with moderate overweight and obesity with and without adjustment for blood pressure and cholesterol concentrations were calculated by the members of a collaboration of prospective cohort studies of healthy, mainly white persons and pooled by means of random-effects models (RRs for categories of BMI in 14 cohorts and for continuous BMI in 21 cohorts; total N = 302 296). RESULTS: A total of 18 000 CHD events occurred during follow-up. The age-, sex-, physical activity-, and smoking-adjusted RRs (95% confidence intervals) for moderate overweight and obesity compared with normal weight were 1.32 (1.24-1.40) and 1.81 (1.56-2.10), respectively. Additional adjustment for blood pressure and cholesterol levels reduced the RR to 1.17 (1.11-1.23) for moderate overweight and to 1.49 (1.32-1.67) for obesity. The RR associated with a 5-unit BMI increment was 1.29 (1.22-1.35) before and 1.16 (1.11-1.21) after adjustment for blood pressure and cholesterol levels. CONCLUSIONS: Adverse effects of overweight on blood pressure and cholesterol levels could account for about 45% of the increased risk of CHD. Even for moderate overweight, there is a significant increased risk of CHD independent of these traditional risk factors, although confounding (eg, by dietary factors) cannot be completely ruled out.

Long-term effects of nutritional group education for persons at high cardiovascular risk.

BACKGROUND: Treatment of persons at high risk for coronary heart disease (CHD) should include nutritional counselling, but little is known about the effects of different types of education. METHODS: In a quasi-experimental study design the effects of a nutritional education programme (1st year: three group sessions by a dietitian; 2nd year: one group session; 3rd year: additional focus on saturated fat; reinforcement by written nutritional messages annually) (intervention group; n=103) are compared with the effects of a posted leaflet containing standard dietary guidelines (control group; n=163). Participants had hypercholesterolemia (6-8 mmol/l) and at least two other CHD risk factors. RESULTS: After 3 years, no significant differences existed in established CHD risk factors between intervention and control groups (adjusted mean net differences: total cholesterol (0 mmol/l), diastolic blood pressure (-1.1 mm Hg; NS), and body weight (+0.3 kg, NS)). Regarding dietary intake, the intervention group had a lower intake of total (net difference -2.0% of energy, SEM 0.9) and saturated fat (-1.2% of energy, SEM 0.4) and a higher fish (+11 g/day, SEM 4) and vegetables consumption (+21 g/day, SEM 10) during the study period (p<0.05 for all). CONCLUSION: A nutritional education programme with group sessions changed dietary intake more effectively than a posted leaflet, but no additional positive effects were observed on established CHD risk factors after three years of follow-up.

Effect of an increased intake of alpha-linolenic acid and group nutritional education on cardiovascular risk factors: the Mediterranean Alpha-linolenic Enriched Groningen Dietary Intervention (MARGARIN) study.

BACKGROUND: The effect of long-term increased intakes of alpha-linolenic acid (ALA; 18:3n-3) on cardiovascular risk factors is unknown. OBJECTIVES: Our objectives were to assess the effect of increased ALA intakes on cardiovascular risk factors and the estimated risk of ischemic heart disease (IHD) at 2 y and the effect of nutritional education on dietary habits. DESIGN: Subjects with multiple cardiovascular risk factors (124 men and 158 women) were randomly assigned in a double-blind fashion to consume a margarine rich in either ALA [46% linoleic acid (LA; 18:2n-6) and 15% ALA; n = 114] or LA (58% LA and 0.3% ALA; n = 168). An intervention group (n = 110; 50% ALA) obtained group nutritional education, and a control group (n = 172; 34% ALA) received a posted leaflet containing the standard Dutch dietary guidelines. RESULTS: Average ALA intakes were 6.3 and 1.0 g/d in the ALA and LA groups, respectively. After 2 y, the ALA group had a higher ratio of total to HDL cholesterol (+0.34; 95% CI: 0.12, 0.56), lower HDL cholesterol (-0.05 mmol/L; -0.10, 0), higher serum triacylglycerol (+0.24 mmol/L; 0.02, 0.46), and lower plasma fibrinogen (-0.18 g/L; -0.31, -0.04; after 1 y) than did the LA group (adjusted for baseline values, sex, and lipid-lowering drugs). No significant difference existed in 10-y estimated IHD risk. After 2 y, the intervention group had lower saturated fat intakes and higher fish intakes than did the control group. CONCLUSIONS: Increased ALA intakes decrease the estimated IHD risk to an extent similar to that found with increased LA intakes. Group nutritional education can effectively increase fish intake.