The bigger the healthier: are the limits of BMI risk changing over time?

The changing relationship between bodyweight and longevity in high- and low-income countries

Standard measures of bodyweight (overweight and obese, for example) fail to reflect differences across populations and technological progress over time. This paper builds on the pioneering work of Hans Waaler (1984) and Robert Fogel (1994) to empirically estimate how the relationship between body mass index (BMI) and longevity varies across high-, middle-, and low-income countries. Importantly, we show that these differences are so profound that the share of national populations above mortality-minimizing bodyweight is not clearly greater in countries with higher overweight and obesity rates (as traditionally defined)-and in fact, relative to current standards, a larger share of low-income countries' populations can be unhealthily heavy.

Prevalence and associated risk factors for mental health problems among young adults in Fiji Island during COVID-19: a cross-sectional study

Introduction

The COVID-19 pandemic has had a significant impact on mental health globally. To understand the impact of the pandemic on mental health in Fiji, this study aimed to investigate the prevalence of anxiety disorder and depression among the young adults.

Method

An online survey was conducted to assess the prevalence of anxiety disorder and depression among the general population in Suva, Fiji during the COVID-19 pandemic. A total of 1,119 Fiji adults participated in the study. The study was conducted between May 20 to June 30, 2022, using a snowball sampling via social media platforms. The Generalized Anxiety Disorder (GAD-7) and Patient Health Questionnaire (PHQ-9) scales were used to measure anxiety and depression, respectively. The COVID-19 related stressors was evaluated using the adapted SARS stressors assessment. Univariate and multivariate logistic regression analysis was performed to determine the factors influencing mental health among respondents.

Results

The result shows that a significant portion of individuals experienced each of the stressors, with the highest prevalence seen for hearing information about the severity of COVID-19. The prevalence of anxiety and depression was found to be 45% and 49%, respectively. Being female, having pre-existing illness and COVID-19 stressors were a risk factor to develop anxiety and depression. On the other hand, employed individuals and having high BMI was a protective factor against developing depression during COVID-19 lockdown.

Conclusion

These findings highlight the importance of addressing the mental health needs of the Fijian population during the COVID-19 pandemic and beyond.

Skin Tone, Race/Ethnicity, and Gender Differences in BMI among New US Immigrants

Scholars have been interested in the relationship between skin tone and health since at least the 1970s; however, no study, to our knowledge, has analyzed a diverse immigrant sample. In this study, we use the New Immigrant Survey and interactions to examine how skin tone and race/ethnicity - alongside gender - jointly pattern BMI among Legal Permanent Residents. Our approach allows for the analysis of BMI among multiple racial/ethnic immigrant groups, while considering skin tone. Our results document that darker skin shades are associated with higher BMI, but only for women. Further, we also tease out the relationship between gender and race/ethnicity for BMI, which allows us to better understand this critical connection for new immigrants' health in the United States. Together, our results highlight that BMI jointly varies by skin tone and race/ethnicity, which emphasizes the importance of an intersectional approach, especially for new immigrant women of color.

The mortality risk of being overweight in the twentieth century: Evidence from two cohorts of New Zealand men

How have health and social mortality risks changed over time? Evidence from pre-1945 cohorts is sparse, mostly from the United States, and evidence is mixed on long-term changes in the risk of being overweight. We develop a dataset of men entering the NZ army in the two world wars, with objectively measured height and weight, and socioeconomic status in early adulthood. Our sample includes significant numbers of indigenous Māori, providing estimates of weight and mortality risk in an indigenous population. We follow men from war's end until death, with data on more than 12,000 men from each war. Overweight and obesity were important risk factors for mortality, and associated with shorter life expectancy. However, the reduction in life expectancy associated with being overweight declined from 5 to 3 years between the two cohorts, consistent with the hypothesis that being overweight became less risky during the twentieth century.

How Relevant Is the Place Where First-Year College Students Live in Relation to the Increase in Body Mass Index?

(1) Objective: This study analyzes the evolution of the body mass index (BMI) throughout the academic year associated with changes in the lifestyle associated with the place where students live during the course, lifestyle design, and health strategies for the university community. (2) Methods: A total of 93 first-year nursing students participated in this study. Data were collected throughout the course by administering self-reported questionnaires about eating habits and lifestyles, weight, and height to calculate their BMI and place of residence throughout the course. Data were analyzed using statistical analysis (Mann–Whitney, chi-square, Student’s t-test, repeated-measures analysis of variance, and least significant difference tests). (3) Results: We found that the mean BMI increases significantly throughout the course among all students regardless of sex, age, eating habits, or where they live during the course. At the beginning of the course, the mean BMI was 22.10 ± 3.64. The mean difference between the beginning of the course and the middle has a value of p-value < 0.015 and between the middle of the course and the end a p-value < 0.009. The group that increased the most is found among students who continue to live in the family nucleus rather than those who live alone or in residence. Students significantly changed their eating and health habits, especially those who live alone or in residence. (4) Conclusions: There is an increase in BMI among students. It is necessary to carry out seminars or talks that can help students understand the importance of good eating practices and healthy habits to maintain their weight and, therefore, their health, in the short, medium, and long term and acquire a good quality of life.

BODY MASS INDEX VALUES IN THE GENTRY AND PEASANTRY IN NINETEENTH AND EARLY TWENTIETH CENTURY POLAND

The aim of this study was to assess the impact of social and occupational status on the BMI of the gentry and peasantry in the Kingdom of Poland at the turn of 19th and early 20th centuries. Use was made of data on the height and weight of 304 men, including 200 peasants and 104 gentlemen, and 275 women, including 200 from the peasantry and 75 from the gentry. Gentlemen were characterized by a greater body height than peasants (169.40 cm and 166.96 cm, respectively), a greater body weight (67.09 kg and 60.99 kg, respectively) and a higher BMI (23.33 kg/m2 and 21.83 kg/m2, respectively). Landowners and intelligentsia had a greater BMI than peasants (23.12 kg/m2 and 24.20 kg/m2 vs 21.83 kg/m2, respectively). In the case of women, there were no statistically significant differences in mean height, weight and BMI by their social position, and in BMI by occupational status. Underweight occurred less frequently in the gentry and more frequently in the peasantry (0.97% and 2.04%, respectively). Overweight was five times more common in gentlemen than in peasants (26.21% and 5.10%, respectively). Differences in the BMI of gentlefolk and peasants resulted from differences in diet and lifestyle related to socioeconomic status.

From Undernutrition to Overnutrition: The Evolution of Overweight and Obesity among Young Men in Switzerland since the 19th Century

OBJECTIVE

The global obesity epidemic continues, new approaches are needed to understand the causes. We analyzed data from an evolutionary perspective, stressing developmental plasticity.

METHODS

We present diachronical height, weight, and BMI data for 702,902 Swiss male conscripts aged 18-20 years, a representative, standardized and unchanged data source.

RESULTS

From 1875 to 1879, the height distribution was slightly left-skewed; 12.1% of the conscripts were underweight, overweight and obesity were rare. The BMI-to-height relationship was positive but not linear, and very short conscripts were particularly slim. Since the 1870s, Swiss conscripts became taller, a trend that markedly slowed in the 1990s. In contrast, weight increased in two distinct steps at the end of the 1980s and again after 2002. Since 2010, BMI did not increase but stabilized at a high level.

CONCLUSIONS

The body of young men adapted differently to varying living conditions over time: First, less investment in height and weight under conditions of undernutrition and food uncertainty; second, more investment in height under more stable nutritional conditions; third, development of obesity during conditions of plateaued height growth, overnutrition, and decreasing physical activity. This example contributes to the evaluation of hypotheses on human developmental plasticity.

Dual energy X-ray absorptiometry spine scans to determine abdominal fat in postmenopausal women

Body composition may be a better predictor of chronic disease risk than body mass index (BMI) in older populations.

OBJECTIVES

We sought to validate spine fat fraction (%) from dual energy X-ray absorptiometry (DXA) spine scans as a proxy for total abdominal fat.

METHODS

Total body DXA scan abdominal fat regions of interest (ROI) that have been previously validated by magnetic resonance imaging were assessed among healthy, postmenopausal women who also had antero-posterior spine scans (n = 103). ROIs were (1) lumbar vertebrae L2-L4 and (2) L2-Iliac Crest (L2-IC), manually selected by two independent raters, and (3) trunk, auto-selected by DXA software. Intra-class correlation coefficients evaluated intra and inter-rater reliability on a random subset (N = 25). Linear regression models, validated by bootstrapping, assessed the relationship between spine fat fraction (%) and total abdominal fat (%) ROIs.

RESULTS

Mean age, BMI, and total body fat were 66.1 ± 4.8 y, 25.8 ± 3.8 kg/m² and 40.0 ± 6.6%, respectively. There were no significant differences within or between raters. Linear regression models adjusted for several participant and scan characteristics were equivalent to using only BMI and spine fat fraction. The model predicted L2-L4 (Adj. R² : 0.83) and L2-IC (Adj. R² : 0.84) abdominal fat (%) well; the adjusted R² for trunk fat (%) was 0.78. Model validation demonstrated minimal over-fitting (Adj. R² : 0.82, 0.83, and 0.77 for L2-L4, L2-IC, and trunk fat, respectively).

CONCLUSIONS

The strong correlation between spine fat fraction and DXA abdominal fat measures make it suitable for further development in postmenopausal chronic disease risk prediction models. Am. J. Hum. Biol. 28:918-926, 2016. © 2016Wiley Periodicals, Inc.

Reducing Societal Obesity: Establishing a Separate Exercise Model through Studies of Group Behavior

The past 50 years has brought attention to high and increasing levels of human obesity in most of the industrialized world. The medical profession has noticed, has evaluated, and has developed models for studying, preventing, and reversing obesity. The current model prescribes activity in specific quantities such as days, minutes, heart rates, and footfalls. Although decreased levels of activity have come from changes revolving around built environments and social networks, the existing medical model to lower body weights by increasing activity remains individually prescriptive. It is not working. The study of societal obesity precludes the individual and must involve group behavioral studies. Such studies necessitate acquiring separate tools and, therefore, require a significant change in the evaluation and treatment of obesity. Finding groups with common activities and lower levels of obesity would allow the development of new models of land use and encourage active lifestyles through shared interests.

Risk of Mortality According to Body Mass Index and Body Composition Among Postmenopausal Women

Obesity, often defined as a body mass index (BMI; weight (kg)/height (m)(2)) of 30 or higher, has been associated with mortality, but age-related body composition changes can be masked by stable BMI. A subset of Women's Health Initiative participants (postmenopausal women aged 50-79 years) enrolled between 1993 and 1998 who had received dual-energy x-ray absorptiometry scans for estimation of total body fat (TBF) and lean body mass (LBM) (n = 10,525) were followed for 13.6 (standard deviation, 4.6) years to test associations between BMI, body composition, and incident mortality. Overall, BMI ≥35 was associated with increased mortality (adjusted hazard ratio (HR) = 1.45, 95% confidence interval (CI): 1.16, 1.82), while TBF and LBM were not. However, an interaction between age and body composition (P < 0.001) necessitated age stratification. Among women aged 50-59 years, higher %TBF increased risk of death (HR = 2.44, 95% CI: 1.38, 4.34) and higher %LBM decreased risk of death (HR = 0.41, 95% CI: 0.23, 0.74), despite broad-ranging BMIs (16.4-69.1). However, the relationships were reversed among women aged 70-79 years (P < 0.05). BMI did not adequately capture mortality risk in this sample of postmenopausal women. Our data suggest the clinical utility of evaluating body composition by age group to more robustly assess mortality risk among postmenopausal women.

A Weighty Issue: Diminished Net Nutrition Among the U.S. Working Class in the Nineteenth Century

Much has been written about the modern obesity epidemic, and historical BMIs are low compared with their modern counterparts. However, interpreting BMI variation is difficult because BMIs increase when weight increases or when stature decreases, and the two have different implications for human health. An alternative measure for net current nutritional conditions is body weight. After controlling for height, I find that African American and white weights decreased throughout the late nineteenth and early twentieth centuries. Farmers had greater average weights than workers in other occupations. Individuals from the South had taller statures, greater BMIs, and heavier weights than workers in other U.S. regions, indicating that even though the South had higher disease rates in the nineteenth century, it had better net nutritional conditions.

Was what ail'd ya what kill'd ya?

Making use of those Union Army veterans for whom death certificates are available, we compare the conditions with which they were diagnosed by Civil War pension surgeons to the causes of death on the certificates. We divide the data between those veterans who entered the pension system early because of war injuries and those who entered the pension system after the 1890 reform that made it available to many more veterans. We examine the correlation between specific medical conditions rated by the surgeons and death causes to gauge support for the hypothesis that death is attributable to something specific. We also examine the correlation between the accumulation of rated conditions to the length of time until death to gauge support for the "insult hypothesis." In general, we find support for both hypotheses. Examining the hazard ratios for dying of a specific condition, there is support for the idea that what ail'd ya' is what kill'd ya'.

Body mass, wealth, and inequality in the 19th century: joining the debate surrounding equality and health

We explore relationships among BMI variation, wealth, and inequality in the 19th century US. There was an inverse relationship between BMI and average state-level wealth and a small, inverse relationship with wealth inequality. After controlling for wealth and inequality, farmers had greater BMI values than workers in other occupations, and blacks had greater BMI values because of nutritional deprivation in utero.

The body mass index of blacks and whites in the United States during the nineteenth century

Body mass index (BMI) values reflect the net balance between nutrition, work effort, and calories consumed to fight disease. Nineteenth-century prison records in the United States demonstrate that the BMI values of blacks and whites were distributed symmetrically; neither underweight nor obese individuals were common among the working class. BMI values declined throughout the nineteenth century. By modern standards, however, nineteenth-century BMIs were in healthy weight ranges, though the biological living standards in rural areas exceeded those in urban areas. The increase in BMIs during the twentieth century did not have its origin in the nineteenth century.

Height and body mass index values of nineteenth-century New York legislators

Previous studies of mid-nineteenth-century American BMI values have used data created by military academies and penitentiaries. This paper uses an alternative data set, constructed from legislative documents in which the heights and weights of New York State legislators were recorded. The results reveal that middle- to upper-middle class Americans maintained BMI values closer to the modern standard than did students and prisoners. The average BMI value among this group was 24 and their height-weight combinations did not greatly diverge from historical mortality risk optima.

BMI distribution/social stratification in Swiss conscripts from 1875 to present

BACKGROUND/OBJECTIVES

We aimed to extend the actual overweight discussion with new unbiased Swiss conscript data from 2005 to 2006, and to present for the first time Swiss data on body mass index (BMI) before 1950 and for the late-nineteenth century.

SUBJECTS/METHODS

For this study, 19-year-old Swiss male conscripts (draft army; Cantons Bern, Zurich, Basel-Stadt and Basel-Land) from the census of 1875-1879, 1933-1939 and 2005-2006 (N=28 033; 2005-2006 census) were included. BMI distribution (World Health Organization (WHO) classification) and social stratification (International Labour Organization classification) were main outcome measures.

RESULTS

Mean BMI of 19-year-old men in Switzerland increased in the 50 years between the 1870s and the 1930s by 0.80 kg/m(2) and between the 1930s and 2005 by 1.45 kg/m(2). The modern BMI sample is much more right skewed and s.d. is higher. Obesity prevalence (according to modern WHO classification) has increased by a factor of 105 from 1870s until present. Over 23% of our representative sample of Swiss men in 2005-2006 had a BMI of over 25 kg/m(2). In 2005-2006, contrary to the nineteenth century, unskilled workers had articulately higher BMI values at the 75th, 90th and 95th percentile than students; 12% of unskilled workers were obese against 2% of students.

CONCLUSIONS

It thus seems that BMI relations between the upper and the lower end of the socio-economic strata changed inversely from the late-nineteenth century to 2005-2006. We further propose that the phenomenon of massive right-skewing BMI distribution between the 1930s and 2005-2006 affected the lower socio-economic strata to a far greater extent than the higher socio-economic group.

Recent declines in chronic disability in the elderly U.S. population: risk factors and future dynamics

As U.S. life expectancy has increased, questions arise as to how the quality of health and functioning in the elderly population has changed. Data from the 1982-2004 National Long-Term Care Survey (NLTCS) suggested that chronic disability prevalence above age 65 declined at an increasing rate with a 2.2% per annum rate of decline from 1999 to 2004 ( 71 ). Inflation-adjusted per capita Medicare expenditure rates in nondisabled persons also declined, 0.9% per annum from 1982 to 2004, which suggests that declines in disability were driven by improving health -- not by increases in per capita health expenditures. Declines in disability prevalence were found in other U.S. national health surveys. Analyses of U.S. Civil War veterans suggest recent disability declines were continuations of declines in both chronic disease and disability occurring over the past century due to improved nutrition, sanitation, and education. Concerns exist about whether disability declines will continue because of recent increases in obesity prevalence.