Body mass trajectory, energy balance, and weight loss as determinants of health and mortality in older adults

Body Mass Index and Mortality in Chinese Older Adults -New Evidence from a Large Prospective Cohort in China

OBJECTIVES

To comprehensively evaluate the association between BMI and death risk in people aged 65 years and over in Shenzhen, China, and suggest the optimal range of body mass index (BMI) for the older adults.

DESIGN

A prospective cohort study.

SETTING

A population-based study of elderly adults in Shenzhen, China.

PARTICIPANTS

359044 Shenzhen Healthy Ageing Research participants aged 65 and over with 4682 deaths during a mean of 1.5 years of follow-up were included in this analysis.

MEASURES

Hazard ratio of all-cause and cause specific mortality risks associated with BMI categories. The association between BMI and all-cause and cause specific mortality were independently estimated by Cox regression model.

RESULTS

Regardless of gender, BMI of 24 -29.9 kg/m2 was a protective factor for death in all ages, while BMI above 30 kg/m2 was still a protective factor for older adults under 70 years old. Regardless of age, BMI at 24-25.9 kg/m2 was associated with lower mortality in men, while BMI at 26-27.9 kg/m2 was associated with lower mortality in women. For the older adults without chronic diseases, BMI at 24-25.9 kg/m2 was also significantly associated with lower mortality. In the analysis of BMI and cause of death, we also found that BMI of 24-25.9 kg/m2 was significantly associated with the lower mortality from cardiovascular disease, cancer, chronic respiratory disease and digestive system disease in China.

CONCLUSION

BMI in the range of 24-25.9 kg/m2 may be protective for mortality in Chinese older adults. Additional more large-scale, multicenter and long-term follow-up studies are needed to confirm these findings in different populations.

New Therapeutic Approaches and Biomarkers for Increased Healthspan

Healthcare costs have increased in developing countries over the last few decades, mostly due to the escalation in average life expectancy and the concomitant increase in age-related disorders. To address this issue, widespread research is now being undertaken across the globe with the aim of finding a way of increasing healthy aging. A number of potential interventions have already shown promise, including lifestyle changes and the use of natural products or pharmaceuticals that may delay the onset of diseases associated with the aging process. In parallel, a number of potential biomarkers have already been identified that can be used for assessing risk of developing age-associated disorders and for monitoring response to therapeutic interventions. This review describes the most recent advances towards the goal of achieving healthier aging with fewer disabilities that may lead to enhanced quality of life and reduced healthcare costs around the world.

Diet and Nutrition Risk Affect Mobility and General Health in Osteoarthritis: Data from the Canadian Longitudinal Study on Aging

BACKGROUND

This study examined whether aspects of diet and nutrition risk explain variance in physical capacity and general health, after controlling for covariates, in Canadian adults with osteoarthritis (OA).

METHODS

This was a cross-sectional study of baseline data from the Canadian Longitudinal Study on Aging (CLSA). Data from 1,404 participants with hand, hip, and/or knee OA were included. A series of regression analyses were conducted with independent variables of food intake (fiber and high calorie snack intake) and nutrition risk; and dependent variables of physical capacity and general health. Physical capacity was characterized through grip strength and a pooled index of four mobility tests. General health was characterized through an index of self-reported general health, mental health, and healthy aging.

RESULTS

Higher fiber intake was related to greater mobility (p = .01). Food intake was not related to any other outcome. Nutrition risk was significantly associated with mobility (p < .001) and general health (p < .001); those with a high nutrition risk classification had poorer general health (p < .001, d = 0.65) than those at low nutrition risk. As well, those with moderate nutrition risk had poorer general health than those with low nutrition risk (p = .001, d = 0.31).

CONCLUSIONS

Nutrition risk screening for older adults with OA provides insight into behavioral characteristics associated with reduced mobility and poorer general health. Also, those consuming greater amounts of fiber demonstrated better mobility. Thus, this research suggests that quality of diet and nutritional behaviors can impact both physical and mental aspects of health in those with OA.

Body mass index and all-cause mortality among older adults

OBJECTIVE

To examine the association between baseline body mass index (BMI, kg/m(2) ) and all-cause mortality in a well-characterized cohort of older persons.

METHODS

The association between BMI (both as a categorical and continuous variable) and all-cause mortality was investigated using 4,565 Geisinger Rural Aging Study participants with baseline age 74.0 ± 4.7 years (mean ± SD) and BMI 29.5 ± 5.3 kg/m(2) over a mean of 10.9 ± 3.8 years of follow-up.

RESULTS

The relationship between BMI (as a continuous variable) and all-cause mortality was found to be U-shaped (P nonlinearity <0.001). Controlling for age, sex, smoking, alcohol, laboratory values, medications, and comorbidity status, underweight (BMI <18.5 kg/m(2) ) individuals had significantly greater adjusted risk of all-cause mortality than persons of BMI 18.5 to 24.9 kg/m(2) (reference range). Participants with overweight (BMI 25.0-29.9 kg/m(2) ) and class I obesity (BMI 30.0-34.9 kg/m(2) ) had significantly lower adjusted-risk of all-cause mortality. Those with classes II/III obesity (BMI ≥ 35.0 kg/m(2) ) did not have significantly greater adjusted-risk of all-cause mortality. Findings were consistent using propensity score weights and among never-smokers with 2- and 5-year lag analysis and among those with no identified chronic disease.

CONCLUSIONS

A U-shaped association was observed between BMI and all-cause mortality with lower risk among older persons with overweight and class I obesity in comparison with those with BMI 18.5 to 24.9 kg/m(2) .

Weight and weight change and risk of acute myocardial infarction and heart failure - the HUNT Study

OBJECTIVES

To delineate the association of weight with cardiovascular health throughout adulthood.

METHODS

We conducted a population-based prospective cohort study of 26 097 community-dwelling individuals who were followed for 11.4 years with measurements of cardiovascular risk factors and common chronic disorders. Body weight and height were directly measured at baseline in 1995-1997 as they had been 10 and 30 years prior to baseline. From these measurements, we estimated average body mass index (BMI) over time and calculated weight change.

RESULTS

The association of average BMI with acute myocardial infarction (AMI) became weaker with adjustment for the most recent BMI measurement, whilst this adjustment had a more limited effect on associations with heart failure (HF) risk. For example, the multi-adjusted hazard ratios for AMI in a comparison of individuals with average BMI until baseline ≥35 kg m(-2) and between 18.5 and 22.4 kg m(-2) decreased from 1.75 [95% confidence interval (CI) 1.04-2.95] to 1.32 (0.73-2.40). The corresponding numbers for HF were 3.12 (1.85-5.27) and 2.95 (1.53-5.71), respectively. The associations between weight change and risk of AMI and HF were U-shaped, with stable weight showing the lowest risk.

CONCLUSION

Sustained overweight or obesity over time is associated with increased risk of HF, even after adjustment for the most recent BMI. For AMI risk, the most recent BMI appears to be the most important. Weight change also increases risks for both outcomes beyond the effects of BMI. Our results suggest that a global epidemic of obesity is likely to increase the incidence of HF, even if BMI in middle age can be controlled.

Low-fat dietary pattern and change in body-composition traits in the Women's Health Initiative Dietary Modification Trial

BACKGROUND

The Women's Health Initiative Dietary Modification (DM) Trial was a randomized controlled trial that compared the effects of a low-fat (≤20% of total energy) or a usual diet in relation to chronic disease risk in postmenopausal women.

OBJECTIVE

We characterized long-term body-composition changes associated with the DM trial and potential modifiers of these associations.

DESIGN

In the DM trial, 48,835 women aged 50-79 y were randomly assigned to intervention (40%) or comparison (60%) groups. We studied a subset with whole-body dual-energy X-ray absorptiometry scans at baseline and during follow-up. Changes in fat mass (FM), lean mass (LM), and percentage body fat between the intervention (n = 1580) and comparison (n = 2731) groups at years 1, 3, and 6 were compared. By using generalized estimating equations, we calculated overall differences between groups and tested for interactions with age, diabetes, race-ethnicity (white, black, and Hispanic), body mass index (BMI), and hormone therapy (HT).

RESULTS

The intervention women experienced significantly greater reductions in percentage body fat, FM, and LM at years 1 and 3 than did women in the comparison group (all P < 0.05). At year 6, only the FM change was significantly different between groups. Overall, the intervention was associated with reductions in percentage body fat (-0.8%; 95% CI: -1.0%, -0.6%), FM (-1.1 kg; 95% CI: -1.3, -0.8 kg), and LM (-0.17 kg; 95% CI: -0.28, -0.06 kg) during follow-up (all P < 0.003). Intervention associations varied by race-ethnicity, BMI, diabetes, and HT and remained significant after adjustment for physical activity.

CONCLUSION

This intervention was associated with modest long-term body-composition changes; the findings were more robust in years 1 and 3. This trial was registered at clinicaltrials.gov as NCT00000611.

Brain size, body size and longevity

In this analysis, we bring together two research fields that have never been associated before: the clinical issue 'Quételet's body-mass index and longevity' and the comparative biological issue 'body-brain allometry'. Comparison of medical and biological data supports the view that body mass index is just a one-to-one mapping of the body-brain-energy balance-a biological variable indicating that an individual maintains its systemic energy homeostasis and therefore is likely to perform well in the coming years.