How weight change is modelled in population studies can affect research findings: empirical results from a large-scale cohort study

Does Retirement and Work Stoppage Impact Body Weight and Waist Circumference Changes in Middle- and Older-Aged Women and Men? Results From the Canadian Longitudinal Study on Aging

This study aimed to examine the impact of employment transitions (ETs) on anthropometric changes among middle-aged and older workers (ages 45y+). Using two waves of data from the Canadian Longitudinal Study on Aging, we analyzed the impact of ETs (stayed working, entered retirement, and stopped working) on change in body weight and waist circumference (WC) on continuous scales as well as categories (≥5% cut-off). Analyses were sex/gender-stratified. Women did not show significant weight or WC change that differed across ETs, but estimated directions suggested those who stopped working were more likely to have ≥5% change in weight. Estimated directions of continuous outcomes for women who stopped working relative to continued workers showed less weight gain and more WC gain. Men who retired gained less weight and had smaller WC gain compared to reference. The findings imply that the short-run impact of exiting the labor force may not exacerbate weight gain.

Association between F2-Isoprostane Metabolites and Weight Change in Older Women: A Longitudinal Analysis

INTRODUCTION

Theoretically, some metabolic traits may predispose older individuals to weight loss during aging, leading to increased all-cause mortality and many serious health issues. Biomarkers to robustly predict progressive weight loss during aging are, however, lacking. We prospectively assessed if urinary levels of F2-isoprostanes and their peroxisomal β-oxidation metabolite, 2,3-dinor-5,6-dihydro-15-F2t-isoprostane (F2-IsoP-M), were associated with subsequent weight loss in middle-aged and older women.

METHODS

Included in the analysis were 2,066 women aged 40-70 years, a subset of a prospective cohort study. F2-isoprostanes (F2-IsoPs) and its β-oxidation metabolite, F2-IsoP-M, were measured in urine using gas chromatography-mass spectrometry. Measurements of anthropometry and exposures to major determinants of body weight were performed at baseline and repeated thrice over 15-year follow-up. The longitudinal associations of F2-IsoP-M and the F2-IsoP-M to its parent compound, F2-IsoP, ratio (MPR) with repeatedly measured weight changes were examined using linear mixed-effect models.

RESULTS

After adjusting for time-varying covariates: energy intake, physical activity, and comorbidity index, among others, levels of F2-IsoP-M and the MPR were both inversely associated with percentage of weight change. Weight in the highest quartile of these two biomarkers was 1.33% (95% CI = -2.41, -0.24) and 1.09% (95% CI = -2.16, -0.02) lower than those in the lowest quartile group, with p for trend of 0.01 and 0.03, respectively. The inverse association was consistently seen across follow-up periods, although appearing stronger with prolonged follow-up. There was no association between the parent compound, F2-IsoPs, and weight change.

CONCLUSION

This study demonstrates the first piece of evidence to associate F2-IsoP metabolism, peroxisomal β-oxidation, with weight loss in older women. Further investigations into the role of lipid peroxidation and peroxisomal β-oxidation in weight change among older individuals are warranted.

Adherence to Healthy and Sustainable Dietary Patterns and Long-Term Chronic Inflammation: Data from the EPIC-Potsdam Cohort

OBJECTIVES

We explored the prospective associations between adherence to a priori chosen dietary patterns, including EAT-Lancet (EAT-L) and Mediterranean (tMDS) diet with long-term inflammatory responses in a German population sample.

DESIGN AND SETTING

Prospective cohort study.

PARTICIPANTS

A subsample of 636 predominantly healthy participants from the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam study who were on average 51-years old at baseline.

MEASUREMENTS

Data was collected repeatedly between 1994/1998 - 2013. At baseline (1994/1998) and 6.8-years later (2001/2005), EAT-L and tMDS scores were derived from available food frequency questionnaires. Stable high, stable low, increasing, and decreasing adherence to EAT-L and tMDS were defined as scoring above/below baseline median at baseline and 6.8-years later. Long-term chronic inflammation was assessed based on the average values of repeated measurements of two inflammatory biomarkers - chemerin and high-sensitivity C-reactive protein (hs-CRP) - in plasma samples collected between 2010/2012 and 2013. Multivariable linear regression analysis adjusted for socio-demographic and lifestyle factors at baseline and in 2010/2012 was used to assess the association between diet adherence and long-term hs-CRP and chemerin concentrations.

RESULTS

Stable high or increasing adherence to EAT-L diet compared to stable low adherence was associated with slight reduction of long-term chemerin concentrations on the long run (stable high: -4.4%; increasing: -4.0%), not reaching statistical significance. Increasing adherence to tMDS compared to stable low adherence was also associated with a minor reduction in chemerin concentrations (-3.6%). Decreasing adherence to tMDS compared stable high adherence was associated with 2.7% higher chemerin. The associations were even less pronounced when hs-CRP was used as an outcome.

CONCLUSIONS

Adherence to healthy and sustainable dietary patterns defined using existing definitions for EAT-L and tMDS were associated with minor and not statistically significant reduction in the concentrations of inflammatory biomarkers on the long run. More research is needed to explore whether following these diets may represent a suitable approach for targeted prevention in the general population.

A systematic review of evidence on employment transitions and weight change by gender in ageing populations

Background

Becoming unemployed is associated with poorer health, including weight gain. Middle- and older-age adults are a growing segment of workforces globally, but they are also more vulnerable to changes to employment status, especially during economic shocks. Expected workforce exits over the next decade may exacerbate both the obesity epidemic and the economic burden of obesity. This review extends current knowledge on economic correlates of health to assess whether employment transitions impact body weight by sex/gender among middle-aged and older adults.

Methods

Eight bibliometric databases were searched between June and July 2021, supplemented by hand-searches, with no restriction on publication date or country. Longitudinal studies, or reviews, were eligible when examining body weight as a function of employment status change in adults ≥50 years. Data extraction and quality appraisal used predefined criteria; reported findings were analysed by narrative synthesis.

Results

We screened 6,001 unique abstracts and identified 12 articles that met inclusion criteria. All studies examined retirement; of which two also examined job-loss. Overall, studies showed that retirement led to weight gain or no difference in weight change compared to non-retirees; however, reported effects were not consistent for either women or men across studies or for both women and men within a study. Reported effects also differed by occupation: weight gain was more commonly observed among retirees from physical occupations but not among retirees from sedentary occupations. Few studies assessed the role of health behaviours; sleep was the least studied. Most studies were medium quality.

Conclusions

Existing studies do not provide a clear enough picture of how employment transitions affect body weight. Firm conclusions on the impact of employment transitions on weight cannot be made without further high-quality evidence that considers the role of gender, job-type, other health behaviours, and other transitions, like job-loss.

Serum 25-hydroxyvitamin D level in relation to weight change and the risk of weight gain in adults of normal weight at baseline: the Norwegian HUNT cohort study

OBJECTIVE

We sought to investigate the relationship of serum 25-hydroxyvitamin D (25(OH)D) level with weight change and the risk of weight gain in an adult population who had normal weight at baseline and were followed up for 11 years.

DESIGN

A population-based prospective cohort study.

SETTING

Nord-Trøndelag, Norway.

PARTICIPANTS

The study included 1501 adults who participated in the second and third surveys of the Nord-Trøndelag Health Study (HUNT2 (1995-1997) and HUNT3 (2006-2008)) and had a normal body mass index ≥18.5 and <25.0 kg/m² at baseline.

PRIMARY AND SECONDARY OUTCOME MEASURES

Relative weight change (%) was calculated as ((HUNT3 weight-HUNT2 weight)/HUNT2 weight×100). Relative annual weight change (%) was calculated as (relative weight change/follow-up years×100). Clinical weight gain was defined as relative weight change ≥5% over the 11 years, while annual weight gain was defined as relative annual weight change >1.25%.

METHODS

Multiple regression models were used to estimate adjusted coefficients for the relative annual weight change and risk ratios (RRs) for the risk of clinical weight gain and of annual weight gain.

RESULTS

Each 25 nmol/L increase in season-standardised serum 25(OH)D level at baseline was associated with a reduction of 0.05% (95% CI -0.11 to 0.01) for relative annual weight change, a 10% (RR 0.90, 95% CI 0.82 to 0.97) reduced risk of clinical weight gain, and a 19% (RR 0.81, 95% CI 0.65 to 1.00) reduced risk of annual weight gain. A statistically significant trend was evident for the risk of clinical weight gain when 25(OH)D levels were treated as a categorical variable (p=0.006).

CONCLUSIONS

The findings suggested an inverse association of serum 25(OH)D level with the risk of clinical weight gain in adults who had normal weight at baseline over 11 years' follow-up.

Associations Between Unhealthy Weight-Loss Strategies and Depressive Symptoms

INTRODUCTION

There appears to be a link between weight loss and improved mental health, but less is known about how using unhealthy weight-loss strategies impacts the odds of reporting depression.

METHODS

This study includes respondents from the National Health and Nutrition Examination Survey from 2005 to 2014 who attempted to lose weight over the past year. Analysis occurred in 2017. Multivariable logistic regression was used to describe associations between all weight-loss strategies, including those grouped as unhealthy (smoking, vomiting, laxatives, skipping meals, and using diet pills), and the adjusted odds of depression (Patient Health Questionnaire-9 score ≥10). The model was then stratified by BMI, sex, race, and antidepressant use to compare the effect of using at least one unhealthy weight-loss strategy and depression within certain populations.

RESULTS

The sample included 6,765 respondents (weighted n=59.2 million, 95% CI=55.5, 62.9 million). Of these respondents, 18.0% (n=1,270) reported using at least one unhealthy weight-loss strategy. In unadjusted analysis, unhealthy weight-loss strategies were generally associated with higher incidence and odds of reporting depression. In multivariable analysis, using at least one unhealthy weight-loss strategy was significantly associated with odds of reporting depression (AOR=1.47, 95% CI=1.14, 1.91, p<0.01). When the model was stratified, this effect was statistically significant among respondents with class I or II obsesity (AOR=2.20, 95% CI=1.56, 3.10, p<0.01); female respondents (AOR=1.46, 95% CI=1.06, 2.00, p=0.02); and respondents who did not use an antidepressant (AOR=1.57, 95% CI=1.14, 2.15, p=0.01).

CONCLUSIONS

Unhealthy weight-loss strategies are associated with increased odds of depression. This may inform screening practices and public health messaging.

Weight change and 15 year mortality: results from the European Prospective Investigation into Cancer in Norfolk (EPIC-Norfolk) cohort study

Studies have reported a higher mortality risk associated with weight loss, particularly in middle-aged and older adults, although some of these studies did find that gaining weight was also associated with an increased mortality risk. We examined changes in weight in relation to mortality in a prospective population-based cohort study of men and women, resident in Norfolk, UK. Participants were assessed at baseline (1993–1997) and at a second examination (1998–2000), as part of the European Prospective Investigation into Cancer and Nutrition (EPIC-Norfolk) study, and followed up to 2015 for mortality. Participants with a self-reported history of cancer or cardiovascular disease, body mass index < 18.5 kg/m² or missing data on adjustment variables, at either time-point were excluded, leaving 12,580 participants, aged 39–78 in 1993–1997, eligible for analyses. Cox proportional hazards models were used to determine Hazard Ratios (HRs) for all-cause (2603 deaths), cardiovascular (749 deaths), cancer (981 deaths), respiratory (226 deaths) and other causes of mortality (647 deaths) by categories of weight change. After multivariate adjustment, the HRs (95% CIs) for all-cause mortality for men and women who lost more than 5 kg were 1.85 (1.48–2.31) and 1.64 (1.31–2.05) respectively. Higher hazards were also found for specific causes of mortality and weight loss > 5 kg. Similar associations were observed after excluding deaths in the first 5 years of follow-up. Results for weight gain were inconclusive. We conclude that objectively measured weight loss, but not weight gain, was associated with subsequent higher mortality risk in this population-based study of middle-aged and elderly men and women. However, undiagnosed, pre-existing disease and the inability to account for weight cycling need to be remembered when interpreting these results. Unravelling the causal pathways underlying this association will require more detailed studies, including that of changes in body composition.

A distributional approach to obtain adjusted comparisons of proportions of a population at risk

BACKGROUND

Dichotomisation of continuous data has statistical drawbacks such as loss of power but may be useful in epidemiological research to define high risk individuals.

METHODS

We extend a methodology for the presentation of comparison of proportions derived from a comparison of means for a continuous outcome to reflect the relationship between a continuous outcome and covariates in a linear (mixed) model without losing statistical power. The so called "distributional method" is described and using perinatal data for illustration, results from the distributional method are compared to those of logistic regression and to quantile regression for three different outcomes.

RESULTS

Estimates obtained using the distributional method for the comparison of proportions are consistently more precise than those obtained using logistic regression. For one of the three outcomes the estimates obtained from the distributional method and from logistic regression disagreed highlighting that the relationships between outcome and covariate differ conceptually between the two models.

CONCLUSION

When an outcome follows the required condition of distribution shift between exposure groups, the results of a linear regression model can be followed by the corresponding comparison of proportions at risk. This dual approach provides more precise estimates than logistic regression thus avoiding the drawback of the usual dichotomisation of continuous outcomes.

Effect of pregnancy intention, postnatal depressive symptoms and social support on early childhood stunting: findings from India

BACKGROUND

According to United Nation Children's Fund, it has been estimated that worldwide about 165 million children were stunted in 2012 and India alone accounts for 38 % of global burden of stunting. This study aims to examine the effect of pregnancy intention and maternal postnatal depressive symptoms on early childhood stunting in India. We hypothesized that effect of pregnancy intention and postnatal depressive symptoms were mediated by social support.

METHODS

We used data from the first wave of Young Lives Study India. Multivariate logistic regression models (using generalized estimation equation) were used to examine the effect of pregnancy intention and postnatal depressive symptoms on early childhood stunting among children aged 5-21 months. The analysis included 1833 children (out of 2011 sample children) that had complete information on pregnancy intention, maternal depression and other variables.

RESULTS

Bivariate results indicate that a higher percent of children born after unintended pregnancy (40 %) were stunted than children of intended pregnancy (26 %). Likewise, the proportion of stunted children was also higher among women with high postnatal depressive symptoms (35 %) than the low level of depression (24 %). Results of multivariate logistic regression model indicate that children born after unintended pregnancy were significantly more likely to be stunted than children born after intended pregnancy (AOR: 1.76, CI: 1.25, 2.48). Similarly, early childhood stunting was also associated with maternal postnatal depressive symptoms (AOR: 1.53, CI: 1.21, 1.92). Moreover, the effect of pregnancy intention and postnatal depressive symptoms on early childhood stunting were not mediated by social support.

CONCLUSIONS

The findings of this study provide conclusive evidence regarding consequences of pregnancy intention and postnatal depressive symptoms on early childhood stunting in India. Therefore, there is a need to identify the women with unintended pregnancy and incorporate the promotion of mental health into their national reproductive and child health programme.

A record linkage study of antidepressant medication use and weight change in Australian adults

OBJECTIVE

Antidepressant use is widespread. While weight gain is a commonly reported side-effect of antidepressant use and has the potential to affect population health, there is little large-scale population-based evidence on the issue, particularly for long-term use (⩾12 months). The aim of this study is to investigate the association between antidepressant use and weight change, including whether this relationship varies according to antidepressant class, recency of use, duration of use and dose.

METHODS

Annual percentage weight change was calculated from self-reported weight at two time-points from 20,751 participants aged ⩾45 years from the 45 and Up Study - a population-based cohort study from New South Wales, Australia. Antidepressant use, ascertained from linked pharmaceutical data, from 19 months before baseline until end of follow-up (mean = 3.3 years of follow-up), was categorised as current, past-only, non-persistent or non-use. The association between antidepressant use and weight change was modelled using linear and multinomial logistic regressions and according to antidepressant class, recency, duration and dose.

RESULTS

Antidepressants were dispensed to 23% of participants (n = 4748) during the study period. Current antidepressant users were significantly more likely to gain >3% of their body weight annually than non-users (adjusted relative risk ratio = 1.19; 95% confidence interval: [1.03, 1.38]); the risk increased with increasing dose among current users (p[trend] = 0.003). Risk of weight gain did not vary significantly according to antidepressant class, recency or duration of use; however, statistical power was limited. No significant associations were found between antidepressant use and weight loss.

CONCLUSION

Current antidepressant use was associated with modest but statistically significant annual gains in weight, with similar effects observed across the different classes of antidepressants used.

Impact of indoor air pollution from the use of solid fuels on the incidence of life threatening respiratory illnesses in children in India

Background

India contributes 24% of the global annual child deaths due to acute respiratory infections (ARIs). According to WHO, nearly 50% of the deaths among children due to ARIs is because of indoor air pollution (IAP). There is insufficient evidence on the relationship between IAP from the use of solid fuels and incidence of life threatening respiratory illnesses (LTRI) in children in India.

Methods

Panel data of children born during 2001–02, from the Young Lives Study (YLS) conducted in India during 2002 and 2006–07 was used to estimate the impact of household use of solid fuels for cooking on LTRI in children. Multivariable two-stage random effects logistic regression model was used to estimate the odds of suffering from LTRI among children from households using solid fuels relative to children from households using other fuels (Gas/Electricity/Kerosene).

Results

Bivariate results indicate that the probability of an episode of LTRI was considerably higher among children from households using solid fuels for cooking (18%) than among children from households using other fuels (10%). Moreover, children from households using solid fuels in both the rounds of YLS were more likely to suffer from one or more than one episode of LTRI compared to children from households using solid fuels in only one round. Two-stage random effects logistic regression result shows that children from households using solid fuels were 1.78 (95% CI: 1.05-2.99) times as likely to suffer from LTRI as those from households using other fuels.

Conclusion

The findings of this paper provide conclusive evidence on the harmful effects of the use of solid fuels for cooking on LTRI in India. The Government of India must make people aware about the health risks associated with the use of solid fuels for cooking and strive to promote the use of cleaner fuels.