The prognostic role of body mass index on mortality amongst the middle-aged and elderly: a competing risk analysis

Physical activity and metabolic syndrome: A population base study (forest and tree model algorithms)

BACKGROUND & AIM

Lifestyle changes, prominently low mobility in recent years, have increased the prevalence of metabolic syndrome (MetS), and cardiovascular disease risk. This study aimed to determine the relationship between physical activity and MetS using modern statistical methods in a population-based study.

METHODS

The target population included 10,663 people aged 40-70 years in phase 1 of the Persian Kharameh cohort study conducted in 2017. The data used in this study had questions about physical activity, demographic, anthropometrics, blood pressure, and biochemical data.

RESULTS

Participants who their activity was within the fourth quarter were 36% less likely to develop MetS than the participants in the first quarter. In the decision-Tree algorithm with all variables, physical activity was significant after gender and comorbidity. With a lack of comorbidities and physical activity less than 2338 Metabolic Equivalent of Task (MET) and age greater than 53 years, the probability was 26.7% for the male population. For the female population, if associated with comorbidities, a history of diabetes in first-degree relatives, or both, the chance of developing MetS was estimated to be 70.4%. In the decision-tree algorithm, 56.0% of the predictions for MetS were due to gender. After gender, the presence of comorbidities, age, occupation, family history of diabetes, place of residence, and physical activity was discovered as the essential variables in predicting and identifying factors associated with MetS, respectively.

CONCLUSION

Modern statistical methods can be used in similar research due to better presentation of results in applied clinical laws. An essential approach for treating the syndrome and preventing its complications is a lifestyle change, including educating about physical activity and promoting it.

Association of Weight at Different Ages and All-Cause Mortality Among Older Adults in the US

Objective: Assess the association of BMI and BMI change with mortality. Methods: Using data from the Wisconsin Longitudinal Study (WLS) on participants born mainly in 1939 (n=4922), we investigated the associations between various measures of BMI across the life course (age 54 BMI; age 65 BMI; age 72 BMI; lifetime maximum BMI; BMI change between ages 54 and 65; BMI change between ages 65 and 72) and mortality. We also assessed whether these associations are mediated by late life health. Results: BMI at age 54 was more strongly associated with late life mortality than BMI at older ages. The association between BMI change and mortality varied based on the timing of weight change. Health at age 72, particularly self-rated health, diabetes, and physical functioning, mediated the observed associations. Conclusion: Knowing older people's weight at midlife and how their weight has changed may be more important in assessing late life mortality risk than their current weight.

Body mass index and 12-year mortality among older Mexican Americans aged 75 years and older

Background

The role of obesity in mortality in the very old and old-oldest Hispanic population has not been studied. The objective of this study was to examine the effect of body mass index (BMI) on 12-year mortality among older Mexican Americans aged 75 years and older.

Methods

Twelve year prospective cohort study consisting of a population-based sample of 1415 non-institutionalized Mexican American men and women aged 75 and older from 5 southwestern states: Arizona, California, Colorado, New Mexico, and Texas. Data was from Wave 5 of the Hispanic Established Population for the Epidemiologic Study of the Elderly (2004/2005–2016). Socio-demographics, body mass index (BMI), self-reported medical conditions, disability, depressive symptoms, falls, Mini-Mental-State-Examination (MMSE), and Short Physical Performance Battery (SPPB) were assessed at baseline during 2004–2005. BMI (Kg/m²) was classified as underweight (< 18.5), normal weight (18.5 to < 25), overweight (25 to < 30), obesity category I (30 to < 35), and obesity category II/morbid obesity (≥ 35). For assessment of mortality, deaths were ascertained through the National Death Index and report from relatives. Cox proportional hazards regression analysis was performed to estimate the hazard ratio (HR) of 12-year mortality as a function of BMI categories at baseline.

Results

The mean BMI was 27.5 ± 1.7 with participants classified as 1.8% underweight, 30.8% normal weight, 39.2% overweight, 20.7% obesity category I, and 7.6% obesity category II/morbid obesity. Mexican Americans aged ≥75 years with overweight or obesity category I had a reduced HR of death (0.82, 95% CI = 0.70–0.96 and 0.75, 95% CI = 0.62–0.91, respectively) over 12-years of follow-up. The HR of death for underweight and obesity category II/morbid obesity participants was 1.59 (95% CI = 1.03–2.45) and 1.12 (95% CI = 0.85–1.46), respectively. Female participants and those with high scores in the MMSE and SPPB had decreased risk of death.

Conclusions

This study showed the protective effect of overweight and obesity on mortality in Mexican Americans above 75 years of age, which might have implications when treating older adults with overweight and obesity.

Factor Analysis of Metabolic Syndrome Components in a Population-Based Study in the South of Iran (PERSIAN Kharameh Cohort Study)

Background:

We aimed to estimate the exploratory factor analysis (EFA) of metabolic syndrome components based on variables including gender, BMI, and age groups in a population-based study with large sample size.

Methods:

This study was conducted on 10663 individuals 40-70 yr old in Phase 1 of the Persian Kharameh cohort study conducted in 2014–2017. EFA of the metabolic syndrome components, including waist circumference (WC), systolic blood pressure (SBP), diastolic blood pressure (DBP), triglyceride (TG), high-density lipoprotein (HDL) and fasting blood sugar (FBS), was performed on all participants by gender, BMI (Body Mass Index), and age groups.

Results:

EFA results in the whole population based on eigenvalues greater than one showed two factors explaining 56.06% of the total variance. Considering factor loadings higher than 0.3, the first factor included: DBP, SBP, and WC, named as hypertension factor. The second factor also included TG, negative-loaded HDL, FBS, and WC, named as lipid factor. Almost similar patterns were extracted based on subgroups.

Conclusion:

MetS is a multi-factorial syndrome. Both blood pressure and lipid had a central role in this study and obesity was an important factor in both ones. Hypertension, having the highest factor loading, can generally be a valuable screening parameter for cardiovascular and metabolic risk assessment.

Changes in Cardiovascular Risk Factors and Cardiovascular Events in the Elderly Population

Background

This study examines changes in the ideal cardiovascular health (CVH) status and whether these changes are associated with incident cardiovascular disease (CVD) and mortality in the elderly Asian population.

Methods and Results

In the Korea National Health Insurance Service–Senior cohort aged ≥60 years, 208 673 participants without prior CVD, including 109 431 who showed changes in CVH status, were assessed. The association of the changes in cardiovascular risk factors with incident CVD was assessed from 2004 to 2014 in the elderly (aged 60–74 years) and very elderly (≥75 years) groups. During the follow‐up period (7.1 years for CVD and 7.2 years for mortality), 19 429 incident CVD events and 24 225 deaths occurred. In both the elderly and very elderly participants, higher CVH status resulted in a lower risk of CVD and mortality. In the very elderly participants, compared with consistently low CVH, consistently high CVH (subhazard ratio, 0.41; 95% CI, 0.23–0.73) was associated with a lower risk of CVD. This trend was consistently observed in the elderly population. In the very elderly participants, total cholesterol level was not informative enough for the prediction of CVD events. In both the elderly and very elderly groups, body mass index and total cholesterol were not informative enough for the prediction of all‐cause mortality.

Conclusions

In both the elderly and very elderly Asian populations without CVD, a consistent relationship was observed between the improvement of a composite metric of CVH and the reduced risk of CVD. Body mass index and total cholesterol were not informative enough for the prediction of all‐cause mortality in both the elderly and very elderly groups.

Body mass index and all-cause mortality in older adults: A scoping review of observational studies

In older age, body composition changes as fat mass increases and redistributes. Therefore, the current body mass index (BMI) classification may not accurately reflect risk in older adults (65+). This study aimed to review the evidence on the association between BMI and all-cause mortality in older adults and specifically, the findings regarding overweight and obese BMI. A systematic search of the OVID MEDLINE and Embase databases was conducted between 2013 and September 2018. Observational studies examining the association between BMI and all-cause mortality within a community-dwelling population aged 65+ were included. Seventy-one articles were included. Studies operationalized BMI categorically (n = 60), continuously (n = 8) or as a numerical change/group transition (n = 7). Reduced risk of mortality was observed for the overweight BMI class compared with the normal BMI class (hazard ratios [HR] ranged 0.41-0.96) and for class 1 or 2 obesity in some studies. Among studies examining BMI change, increases in BMI demonstrated lower mortality risks compared with decreases in BMI (HR: 0.83-0.95). Overweight BMI classification or a higher BMI value may be protective with regard to all-cause mortality, relative to normal BMI, in older adults. These findings demonstrate the potential need for age-specific BMI cut-points in older adults.

The association between body composition and quality of life among elderly Italians

OBJECTIVE

This study aimed to assess the body composition and quality of life in elderly Italian people and to value the association between these variables.

METHODS

Height, weight, humerus breadth, circumferences, skinfolds, and hand grip strength were measured in 256 older adults (age: M: 81.1 ± 7.3, F: 84.9 ± 8.1 years). Body mass index, waist-hip ratio, waist-height ratio, upper-arm areas, and body composition parameters were calculated. Quality of life (QoL) was measured by WHO Quality of Life-BREF questionnaire (WHOQOL-BREF). Differences between sexes were valued. A multiple regression analysis was carried out to assess the influence of nutritional status and of socio-demographic characteristics on QoL.

RESULTS

The participants were in average overweight. Even if the percentage of overweight/obese subjects was high in both sexes, males presented a more centripetal fat distribution. These characteristics, joined to data regarding lower values of arm-muscle area and hand grip strength, put males at greater risk of cardiometabolic diseases. Regarding quality of life assessments, psychological domain showed the worst scores, and, marital status resulted the main explanatory variable for this domain.

CONCLUSIONS

Social care facilities for the elderly people require planning strategies based on health promotion criteria in order to accentuate active ageing interventions to ameliorate the quality of life of residents.

Gastrointestinal symptoms in patients with diabetes mellitus and non-diabetic: A cross-sectional study in north of Iran

BACKGROUND AND AIM

Gastrointestinal (GI) symptoms are common in patients with diabetes mellitus (DM), which involved in high cost of health care and low quality of life. The aim of this study to investigate the prevalence of GI symptoms in diabetic patients referred to the Gastrointestinal and Liver Diseases Research Center (GLDRC), Guilan University of Medical Sciences (Rasht, Iran) using a validated questionnaire.

METHODS

In this descriptive, cross-sectional study, 255 diabetic patients and 255 non-diabetic subjects were recruited. Participants were randomly selected. The questionnaire recorded GI symptoms among the study population.

RESULTS

GI symptoms were reported in 91.4% of diabetic patients, and 42.1% of them were male. The common GI symptoms in diabetic patients were flatulence (33.0%), followed by retrosternal pain (14.9%), belching (13.7%), postprandial fullness (12.5%), and constipation (11.4%). Retrosternal pain, constipation, flatulence, loss of appetite, and abdominal distention were more prevalent in diabetic women than men.

CONCLUSIONS

DM is associated with high prevalence rate of upper and lower GI symptoms. This effect may be linked to gender and poor glycemic control in diabetic patients, but not to type and duration of diabetes.

Analysing cardiovascular risk factors and related outcomes in a middle-aged to older adults population in Iran: a cohort protocol of the Shiraz Heart Study (SHS)

INTRODUCTION

The significant increase in the rate of morbidity and mortality due to cardiovascular diseases has become a health challenge globally. Lack of enough knowledge on the underlying causes in Iran and taking the unique characteristics of the Shiraz metropolitan city (the capital city of Fars Province) into consideration prompted us to conduct the Shiraz Heart Study. The aim of this study is to determine the predisposing elements leading to coronary heart disease, cerebrovascular disease and peripheral arterial disease.

METHODS AND ANALYSIS

In this population-based, prospective study, family physician clinics will become the executive arms. Participants aged 40-70 years old will be recruited to achieve a sample size of 10 000. Socioeconomicta and anthropometric indices supplemented by physical activity, nutritional and psychological questionnaires, as well as routine blood laboratory tests, medical history and electrocardiographic records, will be collected at enrolment in clinics. In addition, blood samples will be obtained to explore the possible role of genetics in outcome occurrence. Follow-up with blood sampling, completion of a lifestyle questionnaire and evaluation of clinical risk factors will be carried out five times in a 2-year interval for all participants. Advanced statistical methods such as mixed model and time-to-event models will be used for data analysis.

ETHICS AND DISSEMINATION

This study is in accordance with the Helsinki Declaration and has been approved by the Research Ethics Committee of Shiraz University of Medical Sciences (No: 2017-358). Signing a written informed consent is the preliminary step. Participants are free to withdraw on their request at any time. Collected data are kept encrypted in a software with authorities' access only. Findings of the study will be published at a national or international scale through peer-reviewed journals.

Obesity Paradox in Caucasian Seniors: Results of the PolSenior Study

OBJECTIVES

To investigate the influence of overweight and obesity on general performance and mortality in seniors.

DESIGN

Cross-sectional multidisciplinary study on ageing of the Polish population.

SETTING

Community-dwelling individuals aged 65 years or older, selected using three-stage stratified, proportional draw.

PARTICIPANTS

4944 Polish Caucasian seniors, aged 65 years or older recruited between October 2007 and October 2010.

MEASUREMENTS

All study subjects underwent measurement of body mass index (BMI), waist circumference (WC), and arm circumference (AC). The physical and cognitive performance was evaluated using the Katz Activities of Daily Living (ADL) score and Mini-Mental State Examination (MMSE), respectively. Morbidity data were obtained from a medical questionnaire. Mortality data were obtained from the Population Register of Poland between October 2015 and October 2018.

RESULTS

Increasing age was associated with a decreased prevalence of obesity (all p<0.001). Higher BMI, WC and AC values were associated with higher ADL and MMSE scores (all p<0.001). On multivariate analysis, all three body measurements in women remained independent predictors of the ADL score (BMI p=0.002, WC p=0.005, AC p<0.001) and MMSE score (p<0.001, p=0.003, p<0.001). In men, physical functioning was associated with AC (p=0.003), and cognitive status was associated with AC (p<0.001) and BMI (p=0.013). There was no association between general obesity, abdominal obesity, or AC with several aging-related adverse conditions. Kaplan-Meier survival curves showed that overweight and obesity were associated with the lowest mortality. On multivariate analysis, BMI and AC values remained independent predictors of mortality. In successfully aging individuals, neither BMI, WC, nor AC remained such predictors.

CONCLUSIONS

Overweight and obesity in Caucasian seniors are not associated with deterioration of physical and cognitive function or with increased mortality.

BMI and all cause mortality: systematic review and non-linear dose-response meta-analysis of 230 cohort studies with 3.74 million deaths among 30.3 million participants

OBJECTIVE

To conduct a systematic review and meta-analysis of cohort studies of body mass index (BMI) and the risk of all cause mortality, and to clarify the shape and the nadir of the dose-response curve, and the influence on the results of confounding from smoking, weight loss associated with disease, and preclinical disease.

DATA SOURCES

PubMed and Embase databases searched up to 23 September 2015.

STUDY SELECTION

Cohort studies that reported adjusted risk estimates for at least three categories of BMI in relation to all cause mortality.

DATA SYNTHESIS

Summary relative risks were calculated with random effects models. Non-linear associations were explored with fractional polynomial models.

RESULTS

230 cohort studies (207 publications) were included. The analysis of never smokers included 53 cohort studies (44 risk estimates) with >738 144 deaths and >9 976 077 participants. The analysis of all participants included 228 cohort studies (198 risk estimates) with >3 744 722 deaths among 30 233 329 participants. The summary relative risk for a 5 unit increment in BMI was 1.18 (95% confidence interval 1.15 to 1.21; I(2)=95%, n=44) among never smokers, 1.21 (1.18 to 1.25; I(2)=93%, n=25) among healthy never smokers, 1.27 (1.21 to 1.33; I(2)=89%, n=11) among healthy never smokers with exclusion of early follow-up, and 1.05 (1.04 to 1.07; I(2)=97%, n=198) among all participants. There was a J shaped dose-response relation in never smokers (Pnon-linearity <0.001), and the lowest risk was observed at BMI 23-24 in never smokers, 22-23 in healthy never smokers, and 20-22 in studies of never smokers with ≥20 years' follow-up. In contrast there was a U shaped association between BMI and mortality in analyses with a greater potential for bias including all participants, current, former, or ever smokers, and in studies with a short duration of follow-up (<5 years or <10 years), or with moderate study quality scores.

CONCLUSION

Overweight and obesity is associated with increased risk of all cause mortality and the nadir of the curve was observed at BMI 23-24 among never smokers, 22-23 among healthy never smokers, and 20-22 with longer durations of follow-up. The increased risk of mortality observed in underweight people could at least partly be caused by residual confounding from prediagnostic disease. Lack of exclusion of ever smokers, people with prevalent and preclinical disease, and early follow-up could bias the results towards a more U shaped association.

Obesity in older persons

PURPOSE OF REVIEW

There is an increasing number of reports suggesting that indicators of obesity for the general adult population may need to be modified; that the magnitude of risk is attenuated or that adiposity may even be protective; and that additional adverse outcomes specific to older persons need to be considered. Finally, there are benefits and adverse effects of weight loss programmes for older persons. This article reviews publications addressing these issues from 2013 to March 2014.

RECENT FINDINGS

BMI was not considered to be as good an indicator of obesity because of loss of muscle mass with age. Higher body weight seems to be protective among older persons with chronic diseases or geriatric syndromes. Increased adiposity together with decreased muscle mass (sarcopenic obesity) is associated with adverse outcomes, although there is no consensus regarding the definition. Intentional weight loss has health benefits but is accompanied by muscle and bone loss, and therefore programmes should include components to counteract these changes.

SUMMARY

The magnitude of health risk associated with obesity is attenuated with age, and mild increase in adiposity may be beneficial for those who are frail and/or with chronic diseases. Weight loss programmes should include resistance exercises to counteract muscle loss.

Mechanisms linking excess adiposity and carcinogenesis promotion

Obesity constitutes one of the most important metabolic diseases being associated to insulin resistance development and increased cardiovascular risk. Association between obesity and cancer has also been well established for several tumor types, such as breast cancer in post-menopausal women, colorectal, and prostate cancer. Cancer is the first death cause in developed countries and the second one in developing countries, with high incidence rates around the world. Furthermore, it has been estimated that 15-20% of all cancer deaths may be attributable to obesity. Tumor growth is regulated by interactions between tumor cells and their tissue microenvironment. In this sense, obesity may lead to cancer development through dysfunctional adipose tissue and altered signaling pathways. In this review, three main pathways relating obesity and cancer development are examined: (i) inflammatory changes leading to macrophage polarization and altered adipokine profile; (ii) insulin resistance development; and (iii) adipose tissue hypoxia. Since obesity and cancer present a high prevalence, the association between these conditions is of great public health significance and studies showing mechanisms by which obesity lead to cancer development and progression are needed to improve prevention and management of these diseases.