Speakable and unspeakable facts about BMI and mortality

Association between body mass index and mental health among nurses: a cross-sectional study in China

PURPOSE

To examine the correlation between body mass index (BMI) and mental well-being in Chinese nurses during the COVID-19 epidemic.

METHOD

This study was conducted in a tertiary hospital using a cross-sectional design. A total of 2,811 nurses were enlisted at Shengjing Hospital in China during the period from March to April, 2022. Information was gathered through a questionnaire that individuals completed themselves. The mental health of the participants was assessed using the Patient Health Questionnaire-9 and the Generalized Anxiety Disorder Assessment-7. Binary logistic regression was used to calculate adjusted odds ratios (ORs) and their corresponding 95% confidence intervals.

RESULTS

The prevalence of nurses experiencing depression and anxiety was 7.8% (219) and 6.7% (189), respectively. Regarding depression after adjustment, the odds ratios (ORs) for each quartile, compared to the lowest quartile, were as follows: 0.91 (95% confidence interval [CI]: 0.53, 1.56), 2.28 (95% CI: 0.98, 3.77), and 2.32 (95% CI: 1.41, 3.83). The p-value for trend was found to be 0.001. The odds ratios (ORs) for anxiety after adjustment were 2.39 (0.83, 4.36), 4.46 (0.51, 7.93), and 2.81 (1.56, 5.08) when comparing the highest quartiles to the lowest quartile. The p-value for trend was 0.009.

CONCLUSION

This study found a positive association between BMI and poor mental health among nurses during the COVID-19 pandemic, particularly in those who were overweight or obesity. The findings could assist in developing interventions and help policy-makers establish appropriate strategies to support the mental health of frontline nurses, especially those who are overweight or obesity.

Association between body mass index and respiratory symptoms in US adults: a national cross-sectional study

The correlation between body mass index (BMI) and the development of cough, shortness of breath, and dyspnea is unclear. Therefore, this study aimed to investigate the association between these parameters. Data from individuals who participated in the National Health and Nutrition Examination Survey between 2003 and 2012 were analyzed. Weighted logistic regression analysis and smoothed curve fitting were used to examine the correlation between BMI and respiratory symptoms. In addition, the relationship between BMI, chronic obstructive pulmonary disease (COPD), and bronchial asthma was examined. Stratified analysis was used to discover inflection points and specific groups. Weighted logistic regression and smoothed curve fitting revealed a U-shaped relationship between BMI and respiratory symptoms. The U-shaped relationship in BMI was also observed in patients with bronchial asthma and COPD. Stratified analysis showed that the correlation between BMI and wheezing and dyspnea was influenced by race. In addition, non-Hispanic black individuals had a higher risk of developing cough than individuals of the other three races [OR 1.040 (1.021, 1.060), p < 0.0001], and they also exhibited an inverted U-shaped relationship between BMI and bronchial asthma. However, the association of BMI with cough, wheezing, dyspnea, COPD, and asthma was not affected by sex. High or low BMI was associated with cough, shortness of breath, and dyspnea, and has been linked to bronchial asthma and COPD. These findings provide new insights into the management of respiratory symptoms and respiratory diseases.

Physiological Responses Associated with Nordic-Walking and Walking in Middle-age Women

This study aimed to analyze the influence of supervised 12-week walking (W) and Nordic-walking (NW) programs on changes in specific physiological parameters in middle-aged women 55.40±7.87 and 52.58±6.91 years of age, respectively. Body mass, fat tissue percentage, muscle tissue percentage, systolic blood pressure, diastolic blood pressure, resting pulse, and maximum oxygen uptake were measured at the beginning and end of the exercise program. Intra- and intergroup differences in physiological parameters as a function of the preparation period were analyzed using bootstrap analysis. Clinically reliable changes for a specific subject in the W and NW programs were analyzed using the Reliable Change Index (RCI). The results of this study indicate that more distinct differences were observed in the NW group. However, both programs improved the parameters studied. Nevertheless, an analysis of the RCI indicates that the W provides results similar to, if not better than, NW for increasing neuromuscular, cardiovascular, and cardiorespiratory fitness. This study leads us to the conclusion that the W is not less efficient than the NW for middle-aged women.

Association between creatinine to body weight ratio and all-cause mortality: a cohort study of NHANES

Research on the relationship between the weight-adjusted skeletal muscle mass index and all-cause mortality is rare, and even rarer is the relationship between the creatinine/body weight (Cre/BW) ratio and all-cause mortality. Therefore, this study aimed to investigate the relationship between the Cre/BW ratio and mortality in individuals with normal renal function. This prospective study used data from the National Health and Nutrition Examination Survey (NHANES) database. A Cox hazard model was used to analyze the relationship between the Cre/BW ratio and mortality risk. In total, 45,459 participants were included, of which 49.97% were women, with an average age of 45.68 ± 18.08 years. The incidence of all-cause mortality was 10.9% among these participants during the median (interquartile range) follow-up of 9.6 (5.2, 14.2) years. After adjusting for all covariates, a U-shaped relationship was found between the Cre/BW ratio and all-cause mortality (P for nonlinearity <0.001), with the lowest risk observed at Cre/BW ratios (×100) between 0.821 and 0.987. In the threshold effect analysis, the Cre/BW ratio (×100) had a threshold value of 0.96. When the Cre/BW ratio (×100) was <0.96, all-cause mortality was negatively associated with the Cre/BW ratio (×100) (0.63 (0.41, 0.97)). In contrast, when the Cre/BW ratio (×100) was ≥0.96, the higher Cre/BW ratio was associated with a greater hazard ratio of all-cause mortality (1.67 (1.41, 1.97)). In conclusion, we report a U-shaped relationship between the Cre/BW ratio and all-cause mortality. Controlling the Cre/BW ratio within a certain range may reduce the risk of all-cause mortality.

The obesity paradox in the stress echo lab: fat is better for hearts with ischemia or coronary microvascular dysfunction

BACKGROUND

Obesity is an independent risk factor for coronary artery disease (CAD), but once CAD has developed it has been associated with improved survival ("obesity paradox").

AIM

To assess how obesity affects prognosis in patients with or without inducible ischemic regional wall motion abnormalities (RWMA) and/or abnormal coronary flow velocity reserve (CFVR) during stress echocardiography (SE).

METHODS

In an observational retrospective two- center study design, we analyzed 3249 consecutive patients (1907 men; age 66 ± 12 years; body mass index, BMI, 26.9 ± 4.1 kg/m²) with known (n = 1306) or suspected (n = 1943) CAD who underwent dipyridamole SE with simultaneous evaluation of RWMA and CFVR. All-cause death was the outcome end-point.

RESULTS

1075 patients were lean (BMI 18.5-24.9 kg/m²), 1523 overweight (BMI 25.0-29.9 kg/m²), and 651 obese (≥30.0 kg/m²). Ischemic test result for RWMA occurred in 28 (3%) lean, 69 (4%) overweight, and 28 (4%) obese patients (p = 0.03). An abnormal CFVR (≤2.0) was found in 281 (26%) lean, 402 (26%) overweight and 170 (26%) obese patients (p = 0.99). During 68 ± 44 months of follow-up, 496 (15%) patients died. At multivariable Cox analysis, BMI ≥ 30 was an independent predictor of reduced mortality in the 878 patients with stress-induced (≥2 segments) RWMA and/or CFVR abnormality (HR 0.58, 95% CI 0.40-0.84; p = 0.003), while showed no effect at univariate analysis in the 2371 patients with no RWMA and normal CFVR (HR 1.04, 95% CI 0.74-1.46; p = 0.84).

CONCLUSIONS

Obesity exerts a "paradoxical" protective effect in patients with stress-induced ischemia and/ or coronary microvascular dysfunction, and shows a neutral effect in patients with normal CFVR and no stress-induced RWMA.

Body mass index and fatal stroke in young adults: A national study

Rates of stroke and obesity have increased in recent years. This study aimed to determine the body mass index (BMI) of fatal stroke cases amongst young adults, their clinical characteristics and the association with BMI with risk factors. All cases aged 15-44 years where death was attributed to stroke for whom BMI was available were retrieved from the National Coronial Information System (1/1/2009-31/12/2016). 179 cases were identified: haemorrhagic (165), ischaemic (5), thrombotic (6), mycotic (3), embolic (0). Proportions in each BMI category were: underweight (5.6%), normal weight (37.4%), overweight (27.4%), obese (29.6%). There was a significant linear trend in the proportion of subarachnoid haemorrhages as BMI increased (p < 0.05), and between higher BMI and hypertension (p < 0.001). There were no group differences in cardiomegaly or left ventricular hypertrophy where known causes were other than hypertension, cardiomyopathy, severe coronary artery atherosclerosis, endocarditis or cerebral arteries atherosclerosis. A history of alcoholism (p < 0.01) was less likely with higher BMI. There was no association between BMI and previous stroke, diabetes, vasculitis, gravid/post-partum, tobacco use, psychostimulant use or injecting drug use. Overweight and obese cases were prominent among young fatalities of stroke. Reducing rates of obesity, and associated hypertension, would be expected to reduce the escalating stoke rates among young adults.

Perspective on Diagnostic Criteria for Obesity and Abdominal Obesity in Korean Adults

Excessive body weight is associated with increased health risks in humans. In general, the risk of mortality increases with greater obesity. The 2018 guideline for the management of obesity by the Korean Society for the Study of Obesity proposed the body mass index (BMI) cut-off levels of 25 kg/m2 and 23 kg/m2 as diagnostic criteria for obesity and overweight (pre-obese) in Korean adults, respectively. Abdominal obesity has been defined as waist circumference (WC) ≥90 cm in men and WC ≥85 cm in women. In this review, the validity of these criteria for Korean adults was examined based on the evidence regarding the associations of obesity index with mortality and morbidity. The American Association of Clinical Endocrinologists/American College of Endocrinology algorithm and American Diabetes Association guideline for the medical care of obese and overweight patients support a BMI of 25 kg/m2 and 23 kg/m2, respectively, as the cut-off levels for Asians (and some ethnicities) corresponding to the BMI values of 30 kg/m2 and 25 kg/m2, respectively, for Caucasians. In the future, the optimal cut-off levels for obesity and abdominal obesity may require adjustment as the demographic characteristics of the Korean population change. In addition, development of more valid indicators that better reflect health risks of obesity is needed.

Confounding by ill health in the observed association between BMI and mortality: evidence from the HUNT Study using offspring BMI as an instrument

Background

The observational association between mortality and body mass index (BMI) is U-shaped, leading to highly publicized suggestions that moderate overweight is beneficial to health. However, it is unclear whether elevated mortality is caused by low BMI or if the association is confounded, for example by concurrent ill health.

Methods

Using HUNT, a Norwegian prospective study, 32 452 mother-offspring and 27 747 father-offspring pairs were followed up to 2009. Conventional hazard ratios for parental mortality per standard deviation of BMI were estimated using Cox regression adjusted for behavioural and socioeconomic factors. To estimate hazard ratios with reduced susceptibility to confounding, particularly from concurrent ill health, the BMI of parents’ offspring was used as an instrumental variable for parents’ own BMI. The shape of mortality-BMI associations was assessed using cubic splines.

Results

There were 18 365 parental deaths during follow-up. Conventional associations of mortality from all-causes, cardiovascular disease and cancer with parents’ own BMI were substantially nonlinear, with elevated mortality at both extremes and minima at 21–25 kg m⁻². Equivalent associations with offspring BMI were positive and there was no evidence of elevated parental mortality at low offspring BMI. The linear instrumental variable hazard ratio for all-cause mortality per standard deviation increase in BMI was 1.18 (95% confidence interval: 1.10, 1.26), compared with 1.05 (1.03, 1.06) in the conventional analysis.

Conclusions

Elevated mortality rates at high BMI appear causal, whereas excess mortality at low BMI is likely exaggerated by confounding by factors including concurrent ill health. Conventional studies probably underestimate the adverse population health consequences of overweight.

Overweight and Abdominal Obesity Association with All-Cause and Cardiovascular Mortality in the Elderly Aged 80 and Over: A Cohort Study

OBJECTIVE

To evaluate the association between overweight and abdominal obesity with all-cause and cardiovascular mortality in the elderly aged 80 and over.

DESIGN

A prospective cohort study.

SETTING

A population-based study of community-dwelling very elderly adults in a city in southern Brazil.

PARTICIPANTS

236 very elderly adults, number that represents 85% of the population aged 80 and over living in the city in the period (mean age 83.4 ± 3.2).

MEASUREMENTS

Overweight and abdominal obesity were assessed using recommended cut-off points for body mass index (BMI), waist circumference (WC), waist-hip ratio (WHR) and waist-height ratio (WHtR). The association between these anthropometric measurements and all-cause and cardiovascular mortality were independently estimated by Cox proportional hazards model. Kaplan-Meier was used to assess survival time.

RESULTS

Increased WC (>80cm F and >94cm M) and WHtR (>0.53 F and >0.52 M) were associated with lower all-cause mortality, but only WHtR remained associated even after controlling for residual confounding (HR 0.55 CI95% 0.36-0.84; p<0.001). Additionally increased WC was independently associated with lower mortality from cardiovascular diseases (HR 0.57 CI95% 0.34-0.95; p<0.030). BMI and WHR did not show significant independent association with mortality in the main analysis.

CONCLUSION

Greater abdominal fat accumulation, as estimated by WC and WHtR, presented an association with lower allcause and cardiovascular mortality in the elderly aged 80 and over, but not by BMI and WHR.

Association between body mass index and mortality in a prospective cohort of Chinese adults

Obesity is associated with an increased risk of diabetes mellitus, hypertension, and coronary artery disease; however, the relation between body mass index (BMI) and the risk of all-cause mortality is controversial. We prospectively examined the relationship between BMI and all-cause mortality in 123,384 Chinese men and women who participated in the Kailuan health examination study from 2006 to 2007 and 2008 to 2009. Cases included 6218 deaths (5770 men and 448 women) that occurred during a mean follow-up period of 7.39 years. Relative risk was adjusted for factors such as age, serum lipid levels (ie, triglyceride, high-density lipoprotein, and low-density lipoprotein cholesterol), history of smoking and drinking, and physical activity, as well as a medical history of hypertension, diabetes, myocardial infarction, and stroke. Within the cohort, the lowest risk of all-cause mortality was seen among persons with a BMI of 24 to 28 kg/m in male, and the risk was elevated among persons with BMI levels lower or higher than that range. Moreover, all-cause mortality was greatest in the group with a BMI of <18.5 kg/m. In contrast, in female, a high BMI was associated with increased mortality, and a BMI of <18.5 kg/m was associated with the lowest risk. Further, a U-shaped association was seen between BMI and the risk of death from any cause among men and women, even after adjusting for confounding factors. In conclusion, underweight was associated with a substantially increased risk of all-cause mortality in males. The excess risk of all-cause mortality with a high BMI, however, was seen among females.

The impact of body mass index on short-term surgical outcomes after laparoscopic hepatectomy, a retrospective study

Background

Surgeons may expect technical difficulties and worse outcomes when performing laparoscopic hepatectomy (LH) on obese patients. The aim of this study is to assess the impact of body mass index (BMI) on short-term surgical outcomes and to verify risk factors of conversion rate and complications of LH.

Methods

Data were collected from 551 patients who underwent attempted LH between August 1998 and April 2013. Patients were classified into four groups depending on their BMI according to the WHO’s definition of obesity for Asia-Pacific region: underweight <18.5 kg/m² (Group1); normal 18.5–23.9 kg/m² (Group2); overweight 24–27.9 kg/m² (Group3); obese ≥ 28 kg/m² (Group4) respectively. Short-term surgical outcomes were compared across the BMI categories. Possible risk factors concerned conversion rate and complications were analyzed.

Results

The overall conversion rate of the 551 patients was 13.07 %. Conversion rate for Group 1, 2, 3, and 4 were 14.3 % (n = 5), 11.2 % (n = 38), 13.0 % (n = 19), and 34.5 % (n = 10) respectively. Patients within the obese group had a much higher conversion rate. The overall complications rate was 11.98 %, where the complication for Group 1, 2, 3, and 4 were 22.9 % (n = 8), 12.7 % (n = 43), 18.2 % (n = 12), and 10.3 % (n = 3) respectively. Patients within the underweight group had a higher complication rate, but it did not reach statistic difference. Obesity and surgical site of left lobe were independent risk factors of conversion. Age, abdominal surgery history, and type of left and right lobe resection were independent risk factors for complications.

Conclusions

In China, obesity increases risk of conversion rate but it dose not affect surgical complications and other short-outcomes after LH.

Electronic supplementary material

The online version of this article (doi:10.1186/s12871-016-0194-1) contains supplementary material, which is available to authorized users.

Obesity among health service providers in Nigeria: danger to long term health worker retention?

INTRODUCTION

Obesity is a global epidemic. There are rising rates of obesity and its associated disorders, especially in developing countries, including among Health Service Providers (HSPs). Obesity is associated with early retirement, increased morbidity and mortality. Thus, obesity has the potential of reducing long-term retention of HSPs in inadequately staffed health systems of developing countries. This study aimed to determine the magnitude of and factors associated with obesity among HSPs of a tertiary health care facility in Lagos, Nigeria.

METHODS

A cross sectional study was carried out with a questionnaire, which included the International Physical Activity Questionnaire short form (IPAQ-SF). Obesity was defined as BMI ≥30kg/m2. Statistical significance was set at p < 0.05.

RESULTS

300 HSPs were recruited, of which 47.7% were medical doctors and dentists, 43.3% were nurses and other categories of HSPs. The mean age and BMI of the HSPs were 39.3(9.0) years and 27.7(4.6) kg/m2 respectively. Eight two (27.3%) HSPs were obese and 134 (44.7%) were overweight, 149(49.7%) had central obesity. After adjusting for confounding variables using multivariate logistic regression, age > 40 years (OR 3.51, p=0.003), female gender (OR 2.84, p=0.007) and earning a monthly salary of ≤ 200,000 naira relative to 201,000-400,000 naira (OR 2.58, p=0.006) were significantly associated with obesity.

CONCLUSION

Obesity was prevalent among these Nigerian HSPs. This calls for concern, especially with the implication of loosing health workers to obesity related disorders and early retirement.

Underweight as a risk factor for respiratory death in the Whitehall cohort study: exploring reverse causality using a 45-year follow-up

Underweight adults have higher rates of respiratory death than the normal weight but it is unclear whether this association is causal or reflects illness-induced weight loss (reverse causality). Evidence from a 45-year follow-up of underweight participants for respiratory mortality in the Whitehall study (N=18 823; 2139 respiratory deaths) suggests that excess risk among the underweight is attributable to reverse causality. The age-adjusted and smoking-adjusted risk was 1.55-fold (95% CI 1.32 to 1.83) higher among underweight compared with normal weight participants, but attenuated in a stepwise manner to 1.14 (95% CI 0.76 to 1.71) after serial exclusions of deaths during the first 5–35 years of follow-up (P_trend<0.001).

Normal-weight obesity: implications for cardiovascular health

We sought to review the epidemiological features and clinical implications of normal-weight obesity. The concept of normal-weight obesity has been recently reported as an important risk factor for cardiovascular disease, metabolic dysregulation, and poor functional outcomes. However, in clinical practice, normal-weight obesity is not commonly recognized. In this review, we examine the clinical significance and important epidemiological outcomes of normal-weight obesity and describe other variants of adiposity and adiposity-related metabolic status. The incorporation of measures of body fat content and distribution in the clinical setting could allow more accurate identification of adiposity-related long-term risk. This could in turn lead to early lifestyle changes and behavioral modifications that are essential to the treatment of obesity.

Why do thin people have elevated all-cause mortality? Evidence on confounding and reverse causality in the association of adiposity and COPD from the British Women's Heart and Health Study

Low adiposity has been linked to elevated mortality from several causes including respiratory disease. However, this could arise from confounding or reverse causality. We explore the association between two measures of adiposity (BMI and WHR) with COPD in the British Women's Heart and Health Study including a detailed assessment of the potential for confounding and reverse causality for each adiposity measure. Low BMI was found to be associated with increased COPD risk while low WHR was not (OR = 2.2; 95% CI 1.3-3.1 versus OR = 1.2; 95% CI 0.7-1.6). Potential confounding variables (e.g. smoking) and markers of ill-health (e.g. unintentional weight loss) were found to be higher in low BMI but not in low WHR. Women with low BMI have a detrimental profile across a broad range of health markers compared to women with low WHR, and women with low WHR do not appear to have an elevated COPD risk, lending support to the hypothesis that WHR is a less confounded measure of adiposity than BMI. Low adiposity does not in itself appear to increase the risk of respiratory disease, and the apparent adverse consequences of low BMI may be due to reverse causation and confounding.

Influence of body fatness distribution and total lean mass on aortic stiffness in nonobese individuals

BACKGROUND

Subjects with normal body mass index but high body fat percentage have higher cardiovascular risk than subjects with normal weight and low fat mass. However, the association of fat distribution and lean mass with carotid-femoral pulse wave velocity (cfPWV) among nonobese apparently healthy individuals has never been assessed.

METHODS

In 136 nonobese volunteers (mean age = 45±9 years; 57% women) without manifest cardiovascular disease, cfPWV was measured by applanation tonometry. Fat and lean mass were measured by dual-energy x-ray absorptiometry.

RESULTS

In univariate analysis, total fat (r = 0.17; P < 0.01), trunk fat (r = 0.27; P < 0.01), and trunk/total fat ratio (r = 0.32; P < 0.01) were correlated with cfPWV. After adjustment for age and mean arterial pressure, only central fat distribution (trunk/total fat ratio) was significantly associated with cfPWV. In the fully adjustment model, there was a significant interaction between fat distribution and lean mass. When the study sample was grouped by fat distribution and total lean mass medians, subjects with central fat distribution and low lean mass (group 4) had higher log-transformed cfPWV than the noncentral fat/low lean mass group (group 2) (0.89, 95% confidence interval (CI) = 0.86-0.92 vs. 0.85, 95% CI = 0.83-0.87; P < 0.01) or the noncentral fat/high lean mass group (group 1) (0.89, 95% CI = 0.86-0.92 vs. 0.84, 95% CI = 0.81-0.87; P < 0.01) after adjustments. Aortic stiffness increased from group 1 to group 4 (P for linear trend < 0.001).

CONCLUSIONS

Among normal weight individuals without manifest cardiovascular disease, the combination of central fat distribution and low lean mass is associated with higher cfPWV. These factors are more closely related to cfPWV than total fat mass.

Body mass index and mortality among Korean elderly in rural communities: Kangwha Cohort Study

Background

The relationship between body mass index (BMI) and mortality may differ by ethnicity, but its exact nature remains unclear among Koreans. The study aim was to prospectively examine the association between BMI and mortality in Korean.

Methods

6166 residents (2636 men; 3530 women) of rural communities (Kangwha County, Republic of Korea) aged 55 and above were followed up for deaths from 1985–2008. The multivariable-adjusted hazard ratios were calculated using the Cox proportional hazards model.

Results

During the 23.8 years of follow-up (an average of 12.5 years in men and 15.7 years in women), 2174 men and 2372 women died. Men with BMI of 21.0–27.4 and women with BMI of 20.0–27.4 had a minimal risk for all-cause mortality. A lower BMI as well as a higher BMI increased the hazard ratio of death. For example, multivariable-adjusted hazard ratios associated with BMI below 16, and with BMI of 27.5 and above, were 2.4 (95% CI = 1.6–3.5) and 1.5 (95% CI = 1.1–1.9) respectively, in men, compared to those with BMI of 23.0–24.9. This reverse J-curve association was maintained among never smokers, and among people with no known chronic diseases. Higher BMI increased vascular mortality, while lower BMI increased deaths from vascular diseases, cancers, and, especially, respiratory diseases. Except for cancers, these associations were generally weaker in women than in men.

Conclusions

A reverse J-curve association between BMI and all-cause mortality may exist. BMI of 21–27.4 (rather than the range suggested by WHO of 18.5–23 for Asians) may be considered a normal range with acceptable risk in Koreans aged 55 and above, and may be used as cut points for interventions. More concern should be given to people with BMI above and below a BMI range with acceptable risk. Further studies are needed to determine ethnicity-specific associations.

Body-composition predictors of mortality in women aged ≥ 75 y: data from a large population-based cohort study with a 17-y follow-up

BACKGROUND

The role of body composition as a risk factor for death remains controversial in older persons.

OBJECTIVE

We determined the role of body-composition variables in mortality in older women.

DESIGN

Longitudinal analyses were performed in a prospective cohort study of older women. Participants were 4574 community-dwelling women aged ≥ 75 y at the baseline visit (between January 1992 and April 1994). Several body-composition variables were assessed by using anthropometric measures and dual-energy X-ray absorptiometry at the baseline visit. The main outcome was overall mortality. Body-composition variables were body mass index (BMI; in kg/m(2)), hip circumference, waist circumference, waist-to-hip ratio, fat mass/height(2), lean mass/height(2), percentage of fat mass, percentage of lean mass, and the lean mass:fat mass ratio.

RESULTS

The mean (± SD) age at baseline was 80.2 ± 3.8 y. During the 17.7 y (IQR: 17.2-18.1 y) of follow-up, 2876 women died. U-shaped in crude analyses and reversed J-shaped relations in adjusted analyses between BMI, hip and waist circumferences, fat mass/height(2), and risk of death were shown. Adjusted risk of death was significantly higher in participants with BMI ≤ 24.6 and fat mass/height(2) ≤ 8.2 kg/m(2). There was a negative linear association between fat mass (%) and risk of death: a 10% increase in fat mass was associated with a 12% reduction of mortality risk (adjusted HR: 0.88; 95% CI: 0.84, 0.92; P < 0.001). Linear and statistically significant relations were shown between lean mass/height(2) and risk of death in crude but not adjusted analyses.

CONCLUSIONS

Risk of mortality was consistently higher in older women with low adiposity. No lean mass indicator was associated with risk of death. Clinicians should be alerted by low adiposity in older women.

Increased body fat rather than body weight has harmful effects on 4-year changes of renal function in the general elderly population with a normal or mildly impaired renal function

Background

With increasing age, body fat increases and muscle mass reduces. Even people with a normal weight may have a higher percentage of body fat. The aim of this study is to investigate the association between increased body fat and renal function decline (RFD) in the general elderly population with normal or mildly impaired renal function.

Method

We conducted a prospective study of 615 healthy individuals in the general Korean population aged ≥60 years who participated in two health screening check-ups separated by a 4-year period. Obesity was defined as the highest sex-specific tertiles of the percentage body fat (PBF). The main outcome was changes of estimated glomerular filtration rate (eGFR) during the 4 years. Significant RFD was defined as a decrease of eGFR over the upper quartile (≤−2.1% per year).

Results

The mean age was 67.2±6.6 years. The median value of the absolute decline in the eGFR and the percent change was −3.0 mL/minute/1.73 m² and −0.87%/year in men and −3.1 mL/minute/1.73 m² and −0.89%/year in women, respectively. When stratified by sex-specific PBF tertiles, pronounced differences were observed in both sexes; those at the highest tertile of PBF showed the greatest decline in eGFR. Even after adjustments for traditional risk factors of RFD, PBF was independently associated with eGFR changes (β=−0.181; P<0.001). In addition, the harmful effect of a high PBF was consistently found in subjects with a normal weight, too (β=−0.141; P=0.006). Cases of significant RFD occurred in 181 participants (29.4%), and the risk was higher in obese participants as compared with the nonobese participants. The odd ratios (95% confidence interval) for significant RFD were 2.76 (1.28–7.74) in men and 2.02 (1.06–4.43) in women in a whole population and 3.15 (1.03–18.52) in men and 1.44 (1.01–3.28) in women with a normal weight, respectively.

Conclusion

Among the elderly population without comorbidities, increased body fat has a harmful effect on RFD, irrespective of body weight.

A new predictive equation for evaluating women body fat percentage and obesity-related cardiovascular disease risk

BACKGROUND

Obesity represents a global public health problem due to its association with cardiovascular diseases and reduced lifespan. The most widely used classification of obesity is expressed as Body Mass Index (BMI); however, this formula is an imprecise adiposity measurement that ignores several important factors involved. Body Adiposity Index (BAI) was more recently proposed as an indirect evaluation of percentage body fat (PBF). PBF is a direct measure of person's relative body fat and a better predictor of obesity-related risk diseases than BMI and BAI. Since obesity and consequent diseases are considered epidemic, new accurate formulas for epidemiological studies are of interest to the scientific community. Because direct measurement of body composition could be quite expensive, the aims of our work were to analyse the distributions of PBF by Dual X-ray absorptiometry, and the creation of new predictive equation using only anthropometric measures that could be helpful to clinicians to assess easily body fat of female patients.

METHODS/RESULTS

A sample of 1,031 Caucasian Italian women was recruited and BMI, BAI and PBF were evaluated. With the aim of developing a predictive model of PBF a multivariate regression model was fitted to observed data.

CONCLUSIONS

The definition of universally recognized PBF by gender and age could have public health implications. In this study, we developed a new predictive PBF equation that does not require the use of medical instruments or skilled measurement techniques and that may be easily applicable to Italian women.

Social network characteristics and body mass index in an elderly Korean population

Objectives

Research has shown that obesity appears to spread through social ties. However, the association between other characteristics of social networks and obesity is unclear. This study aimed to identify the association between social network characteristics and body mass index (BMI, kg/m²) in an elderly Korean population.

Methods

This cross-sectional study analyzed data from 657 Koreans (273 men, 384 women) aged 60 years or older who participated in the Korean Social Life, Health, and Aging Project. Network size is a count of the number of friends. Density of communication network is the number of connections in the social network reported as a fraction of the total links possible in the personal (ego-centric) network. Average frequency of communication (or meeting) measures how often network members communicate (or meet) each other. The association of each social network measure with BMI was investigated by multiple linear regression analysis.

Results

After adjusting for potential confounders, the men with lower density (<0.71) and higher network size (4-6) had the higher BMI (β=1.089, p=0.037) compared to the men with higher density (>0.83) and lower size (1-2), but not in the women (p=0.393). The lowest tertile of communication frequency was associated with higher BMI in the women (β=0.885, p=0.049), but not in the men (p=0.140).

Conclusions

Our study suggests that social network structure (network size and density) and activation (communication frequency and meeting frequency) are associated with obesity among the elderly. There may also be gender differences in this association.

Association of body mass index with cause specific deaths in Chinese elderly hypertensive patients: Minhang community study

Background

Most studies have suggested that elevated body mass index (BMI) was associated with the risk of death from all cause and from specific causes. However, there was little evidence illustrating the effect of BMI on the mortality in elderly hypertensive patients in Chinese population.

Methods

The information of 10,957 hypertensive patients at baseline not less than 60 years were from Xinzhuang, a town in Minhang district of Shanghai, was extracted from the Electronic Health Record (EHR) system. All study participants were divided into eight categories of baseline BMI (with cut-points at 18, 20, 22, 24, 26, 28 and 30 kg/m²). Relative hazard ratio of death from all cause, cardiovascular and non-cardiovascular cause by baseline BMI groups were calculated, standardized for sex, age, smoking, drinking, physical activity, systolic blood pressure, history of cardiovascular disorders, serum lipid disturbance, diabetes mellitus and antihypertensive drug treatment.

Results

During follow up (median: 3.7 years), 561 deaths occurred. Underweight (BMI<18 kg/m²) was associated with significantly increased mortality from all cause mortality (OR: 2.00; 95% CI: 1.43–2.79) and non cardiovascular mortality (OR: 2.76; 95% CI: 1.87–4.07), but not with cardiovascular mortality. For the cause specific analysis, the underweight was associated significantly with neoplasms (OR: 2.15; 95% CI: 1.16–4.00) and respiratory disorders (OR: 3.41; 95% CI: 1.64–7.06). The results for total mortality and specific cause mortality were not influenced by sex, age and smoking status.

Conclusion

Our study revealed an association between underweight and increased mortality from non-cardiovascular disorders in elderly hypertensive patients in Chinese community. Overweight and obesity were not associated with all cause or cause specific death.

A community-based cross-sectional and longitudinal study uncovered asymptomatic proteinuria in Japanese adults with low body weight

Although proteinuria is highly prevalent in obese individuals, the association between proteinuria and low body weight is equivocal. In this study we determine whether low body weight is more strongly associated with proteinuria compared with normal weight. The association between body mass index (BMI) and proteinuria was examined in a cross-sectional study of 62,582 asymptomatic individuals aged 20-70 years without known kidney diseases recruited, based on the results of medical checkups in 1999. We also examined the incidence of recurrent or nonrecurrent proteinuria in an 8-year longitudinal analysis of 12,493 individuals without proteinuria at baseline. The prevalence of proteinuria showed a J-shaped relationship with BMI. Multivariate regression analysis showed that BMI of 27.0 kg/m(2) and above or 18.9 kg/m(2) and less was significantly associated with proteinuria relative to BMI 21.0-22.9 kg/m(2), even after adjusting for relevant cardiometabolic risk factors. In the longitudinal study, similar J-shaped relationships between the incident rates of proteinuria and baseline BMI groups were observed at post-baseline checkups. Baseline BMI 27.0 kg/m(2) and above was associated with significantly greater risk for recurrent and nonrecurrent proteinuria, whereas BMI 18.9 kg/m(2) and less was only associated with nonrecurrent proteinuria. Thus, obesity and low body weight may be associated with different types of proteinuria independent of cardiometabolic risk factors.

Predicting factors for death from other causes in patients with localized renal cell carcinoma

Purpose

To identify the predictors of death from other causes in patients with localized renal cell carcinoma (RCC).

Materials and Methods

We identified 1,101 patients with pathologically confirmed T1 or T2 RCC with a follow-up duration of over 6 months. Survival according to the cause of death was evaluated by using the Kaplan-Meier analysis with log-rank test. Prognostic factors for death from other causes were assessed by multivariate analysis using the Cox proportional hazard regression model. Once the prognostic factors were identified, a risk-group variable was created by counting the number of unfavorable features present for each patient.

Results

The median follow-up was 62 months, and RCC-related death occurred in 50 patients (4.5%), whereas death from other causes occurred in 47 (4.3%). Patients who died from other causes had a higher American Society of Anesthesiologist (ASA) score (26.1% vs. 10.2%; p=0.044), older age (63.4 years vs. 55.0 years; p<0.001), smaller mass size (5.1 cm vs. 7.9 cm; p<0.001), and lower nuclear grade (p=0.003). In the multivariate Cox regression analysis, older age, higher ASA score, and lower body mass index were independent factors predicting death from other causes in patients with localized RCC. On the basis of the number of risk factors for death from other causes, the 5-year other-cause-specific survival was 98.3% (0 risk factors), 84.7% (1 risk factor), and 67.6% (2 or 3 risk factors), respectively (p<0.001).

Conclusions

Older age, higher ASA score, and lower body mass index were independent predictors of death from other causes in patients with localized RCC.

Adiposity rather than BMI determines metabolic risk

BACKGROUND AND AIM

There is increasing evidence suggesting that WHO body mass index (BMI) cut-off values are outdated and should not be applied to different population. To overcome misclassifications, direct measurements of percentage body fat (PBF) would be a better tool for preobesity and obesity diagnosis. The aim of this study was to analyze the body composition in a adult population in Centre-South of Italy, by age and gender, and to verify the accordance between BMI and PBF cut-off points for health status classification.

METHODS

The total subject pool cover a total of 4408 participants adults. A completed screening of anthropometry and body composition by Dual X-ray Absorptiometry, (DXA) was assessed on 3.258 subjects.

RESULTS

Distributions and quantitative reliable estimates of PBF, total body fat and lean, according to gender and age are provided. The prevalence of "at risk" subjects (preobese and obese) was 69% and 85%, for men and women respectively, according to PBF cut-off points. The agreement of BMI and PBF categories resulted low for the total and male population, even scarce for female population (all P ≤ 0.001). The false negative classification of BMI was stronger for women than men and for younger than older subjects.

CONCLUSIONS

Screening for adiposity in subjects with a normal BMI could better identify those at higher risk for cardiometabolic disturbances and cardiovascular mortality. The herein used cut-offs points of PBF, by age and gender, may provide a useful reference in clinical settings and public health services, in particular for the Italian Caucasian population.

Anthropometric, body composition and health determinants of active ageing: a gender approach

This study applied a gender perspective to establish some of the anthropometric, body composition, health and socio-cultural determinants of active ageing. The variable 'active ageing' (presence/absence) was created based on cognitive and disability/illness/physical functioning, subjective health, satisfaction with life and productive activity performed, and used in predictive models to establish its relationship with anthropometric variables, physical health indicators and educational level. The sample consisted of 456 home-living individuals (169 men and 287 women; age range 54-75 years) from Madrid and Toledo in Spain. The women had a higher prevalence of obesity than the men (37.6% vs 29.0%), significantly greater fat accumulation in the abdominal area and worst perceived health (p=0.003). The frequency of active agers is higher in men than in women (38.4% vs 21.9%; p<0.001). Men and women were found to have distinctive ageing patterns. Health factors condition the presence of active ageing in women, while education factors are also relevant in men.

The relationship between body size and mortality in the linked Scottish Health Surveys: cross-sectional surveys with follow-up

OBJECTIVE

To investigate the relationship between body mass index (BMI), waist circumference (WC) or waist-hip ratio (WHR) and all-cause mortality or cause-specific mortality.

DESIGN

Cross-sectional surveys linked to hospital admissions and death records.

SUBJECTS

In total, 20,117 adults (aged 18-86 years) from a nationally representative sample of the Scottish population.

MEASUREMENTS

Cox proportional hazards models were used to estimate hazard ratios (HRs) for all-cause, or cause-specific, mortality. The three anthropometric measurements BMI, WC and WHR were the main variables of interest. The following were adjustment variables: age, gender, smoking status, alcohol consumption, survey year, social class and area of deprivation.

RESULTS

BMI-defined obesity (≥ 30 kg m(-2)) was not associated with increased risk of mortality (HR = 0.93; 95% confidence interval = 0.80-1.08), whereas the overweight category (25-<30 kg m(-2)) was associated with a decreased risk (0.80; 0.70-0.91). In contrast, the HR for a high WC (men ≥ 102 cm, women ≥ 88 cm) was 1.17 (1.02-1.34) and a high WHR (men ≥ 1, women ≥ 0.85) was 1.34 (1.16-1.55). There was an increased risk of cardiovascular disease (CVD) mortality associated with BMI-defined obesity, a high WC and a high WHR categories; the HR estimates for these were 1.36 (1.05-1.77), 1.41 (1.11-1.79) and 1.44 (1.12-1.85), respectively. A low BMI (<18.5 kg m(-2)) was associated with elevated HR for all-cause mortality (2.66; 1.97-3.60), for chronic respiratory disease mortality (3.17; 1.39-7.21) and for acute respiratory disease mortality (11.68; 5.01-27.21). This pattern was repeated for WC but not for WHR.

CONCLUSIONS

It might be prudent not to use BMI as the sole measure to summarize body size. The alternatives WC and WHR may more clearly define the health risks associated with excess body fat accumulation. The lack of association between elevated BMI and mortality may reflect the secular decline in CVD mortality.

Association between body-mass index and risk of death in more than 1 million Asians

BACKGROUND

Most studies that have evaluated the association between the body-mass index (BMI) and the risks of death from any cause and from specific causes have been conducted in populations of European origin.

METHODS

We performed pooled analyses to evaluate the association between BMI and the risk of death among more than 1.1 million persons recruited in 19 cohorts in Asia. The analyses included approximately 120,700 deaths that occurred during a mean follow-up period of 9.2 years. Cox regression models were used to adjust for confounding factors.

RESULTS

In the cohorts of East Asians, including Chinese, Japanese, and Koreans, the lowest risk of death was seen among persons with a BMI (the weight in kilograms divided by the square of the height in meters) in the range of 22.6 to 27.5. The risk was elevated among persons with BMI levels either higher or lower than that range--by a factor of up to 1.5 among those with a BMI of more than 35.0 and by a factor of 2.8 among those with a BMI of 15.0 or less. A similar U-shaped association was seen between BMI and the risks of death from cancer, from cardiovascular diseases, and from other causes. In the cohorts comprising Indians and Bangladeshis, the risks of death from any cause and from causes other than cancer or cardiovascular disease were increased among persons with a BMI of 20.0 or less, as compared with those with a BMI of 22.6 to 25.0, whereas there was no excess risk of either death from any cause or cause-specific death associated with a high BMI.

CONCLUSIONS

Underweight was associated with a substantially increased risk of death in all Asian populations. The excess risk of death associated with a high BMI, however, was seen among East Asians but not among Indians and Bangladeshis.

Normal weight obesity: a risk factor for cardiometabolic dysregulation and cardiovascular mortality

AIMS

We hypothesized that subjects with a normal body mass index (BMI), but high body fat (BF) content [normal weight obesity (NWO)], have a higher prevalence of cardiometabolic dysregulation and are at higher risk for cardiovascular (CV) mortality.

METHODS AND RESULTS

We analysed 6171 subjects >20 years of age from the Third National Health and Nutrition Examination Survey (NHANES III) and the NHANES III mortality study, whose BMI was within the normal range (18.5-24.9 kg/m(2)), and who underwent a complete evaluation that included body composition assessment, blood measurements, and assessment of CV risk factors. Survival information was available for >99% of the subjects after a median follow-up of 8.8 years. We divided our sample using sex-specific tertiles of BF%. The highest tertile of BF (>23.1% in men and >33.3% in women) was labelled as NWO. When compared with the low BF group, the prevalence of metabolic syndrome in subjects with NWO was four-fold higher (16.6 vs. 4.8%, P < 0.0001). Subjects with NWO also had higher prevalence of dyslipidaemia, hypertension (men), and CV disease (women). After adjustment, women with NWO showed a significant 2.2-fold increased risk for CV mortality (HR = 2.2; 95% CI, 1.03-4.67) in comparison to the low BF group.

CONCLUSION

Normal weight obesity, defined as the combination of normal BMI and high BF content, is associated with a high prevalence of cardiometabolic dysregulation, metabolic syndrome, and CV risk factors. In women, NWO is independently associated with increased risk for CV mortality.

The association between BMI and mortality using offspring BMI as an indicator of own BMI: large intergenerational mortality study

OBJECTIVES

To obtain valid estimates of the association between body mass index (BMI) and mortality by using offspring BMI as an instrumental variable for own BMI.

DESIGN

Cohort study based on record linkage, with 50 years of follow-up for mortality. Associations of offspring BMI with all cause and cause specific maternal and paternal mortality were estimated as hazard ratios per standard deviation of offspring BMI.

SETTING

A large intergenerational prospective population based database covering the general population of Sweden.

PARTICIPANTS

More than one million Swedish parent-son pairs.

RESULTS

The final dataset analysed contained information on 1 018 012 mother-son pairs (122 677 maternal deaths) and 1 004 617 father-son pairs (242 126 paternal deaths). For some causes of death, the patterns of associations between offspring BMI and mortality were similar to those seen for own BMI and mortality in previous studies. Parental mortality from diabetes, coronary heart disease, and kidney cancer had the strongest positive associations with offspring BMI (for example, hazard ratio (HR) for coronary heart disease per standard deviation increase in offspring BMI for mothers 1.15, 95% CI 1.14 to 1.17 and for fathers 1.10, 1.09 to 1.11). However, in contrast to the inverse association of own BMI with lung cancer and respiratory disease mortality seen in other studies, there was a positive association between offspring BMI and lung cancer mortality in mothers (1.12, 1.09 to 1.15) and fathers (1.03, 1.02 to 1.05) and between offspring BMI and respiratory mortality in mothers (1.05, 1.02 to 1.08) and fathers (1.02, 1.00 to 1.04). Associations of own BMI and offspring BMI with all cause, cardiovascular disease related, and non-cardiovascular disease related mortality were compared in a subset of father-son pairs (n=72 815). When offspring BMI was used as an instrumental variable for paternal BMI, the causal association between BMI and paternal cardiovascular disease mortality (HR per standard deviation of BMI 1.82, 95% CI 1.17 to 2.83) was stronger than that indicated by the directly observed association between own BMI and cardiovascular disease mortality (1.45, 1.31 to 1.61).

CONCLUSIONS

Use of offspring BMI as a predictor of own BMI, a technique that avoids problems of reverse causality, suggests that positive associations of BMI with all cause and cardiovascular mortality may be underestimated in conventional observational studies. Use of offspring BMI instead of own BMI in analyses of respiratory disease and lung cancer mortality, for which previous studies have reported consistent and strong inverse associations with own BMI, suggests that such studies have overstated the apparent adverse consequences of lower BMI with respect to these outcomes.