The U-shaped association of body mass index with mortality: Influence of the traits height, intelligence, and education

Associations of benzodiazepine use with cognitive ability and age-related cognitive decline

BACKGROUND

It remains uncertain whether long-term use of benzodiazepines is associated with age-related cognitive decline, and if cognitive ability in early life is the driver of any association. This study examines the association of cognitive ability in young adulthood with later use of benzodiazepines and explores whether the use of benzodiazepines during adult life is associated with cognitive decline in late midlife.

METHODS

The study samples include cognitive tests on the Børge Priens Prøve (BPP) from the conscription board examination (age 19 years) from 335 513 men born 1949-1961 and data from re-examinations of 5183 men 44 years later. Cognitive decline was defined as the difference between scores at the conscription board and the re-examination. Information on purchases of benzodiazepines was obtained from the Danish National Prescription Registry, 1995-2022. Associations were analysed using Cox proportional hazards and linear regression.

RESULTS

In total, 120 911 (36%) men purchased benzodiazepines during a follow-up of 20 years. Lower cognitive scores in young adulthood were associated with a higher risk of initiating benzodiazepines (hazard ratio [95% CI] = 0.71[0.68-0.75]). Men with the highest cumulative use of benzodiazepines had larger cognitive decline (β-coefficient [95% CI] = -1.66 [-2.09 to -1.23] BPP scores) compared with never users. Current benzodiazepine users showed a larger cognitive decline than never users (β-coefficient [95% CI] = -2.42[-3.18 to -1.66] BPP scores) and this partially explained the above association. These estimates for cognitive decline were relatively small and may lack clinical relevance.

CONCLUSION

Low cognitive ability increases the risk of benzodiazepine use in adulthood and cognitive decline is more pronounced in those with the highest benzodiazepine use compared with never-use, but the difference lacks clinical significance.

Cognitive ability, education, height and body mass index in relation to risk of schizophrenia and mortality following its diagnosis

This study examines the hypotheses that the traits of higher IQ, longer education and taller height are associated with lower risk of death as compared to traits of low IQ, short education, and short height in men with schizophrenia compared to men without schizophrenia. In total, 937,919 men born 1939-59 and 1983-1997 with information from conscription were followed for incident schizophrenia in Danish registries. Higher levels of cognitive ability, longer education, and taller height were associated with fewer cases of schizophrenia. In a sub-sample of 652,368 men with information on body mass index, underweight was associated with more and overweight and obesity were associated with fewer cases of schizophrenia compared with normal weight. Higher cognitive ability, longer education, and taller height were associated with fewer deaths from both natural and unnatural causes in both men with and without schizophrenia. Underweight was associated with more deaths from natural and unnatural causes, whereas overweight and obesity were associated with more deaths from natural causes and fewer deaths from unnatural causes in both groups of men. Due to interaction, tall height and long educational duration were associated with fewer deaths from natural causes, and obesity was associated with fewer deaths from unnatural causes among men with schizophrenia compared to men without. In conclusion, traits in young adulthood are associated with higher mortality in men with and without schizophrenia, but traits of long educational duration and obesity seem to be especially important for lower mortality in men with schizophrenia.

U-shaped link of health checkup data and need for care using a time-dependent cox regression model with a restricted cubic spline

We explored risk indicators likely to result in older adults needing certified long-term care in Japan and ascertained whether this relationship forms a U-shaped link. We analyzed a community-based cohort of residents in Kitanagoya City, Aichi Prefecture, Japan. Participants were 3718 individuals aged 65 years and above who underwent health examinations between April 1, 2011 and March 31, 2012. For continuous clinical variables, we applied a time-dependent Cox regression model. Two types of models were applied-a linear and nonlinear model with restricted cubic splines-to assess the U-shaped association. Statistical significance (set at 0.05) for the nonlinearity was tested by comparing the spline and linear models. Among the participants, 701 were certified as needing Level 1 care or higher during a follow-up. Among the continuous clinical variables, the nonlinear model for body mass index, systolic blood pressure, high-density lipoprotein cholesterol, alanine aminotransferase, aspartate aminotransferase, and γ-glutamyl transpeptidase revealed significant U-shaped associations as compared with the linear model in which the outcome was a certification of the need for nursing care. These results provide an important insight into the usefulness of nonlinear models for predicting the risk of such certification.

Impact of PFAS exposure on prevalence of immune-mediated diseases in adults in the Czech Republic

BACKGROUND

Per- and polyfluoroalkyl substances (PFASs) are emerging environmental contaminants with multiple hazardous properties including immunomodulation potency. Human exposure to PFASs has been associated with various immune-mediated diseases and outcomes. This study aimed to investigate the association between PFAS exposure and immune-mediated diseases such as allergies, eczemas, and autoimmune diseases in a population of adults in the Czech Republic.

METHODS

This study included 309 adults from the Central European Longitudinal Study of Parents and Children: Young Adults (CELSPAC: YA). 12 PFASs were measured in participants' serum by HPLC-MS/MS, 3 PFASs were removed from the subsequent analyses due to low detection frequency. The associations of 9 PFASs with 9 immune-mediated diseases were assessed by logistic regression. Furthermore, Bayesian kernel machine regression (BKMR) was used to estimate the effect of the PFAS mixture on immune-mediated diseases. All analyses were adjusted for sex, age, BMI, smoking, education, and family history of immune-mediated diseases. In cases of a statistically significant interaction of PFASs and sex, stratified analyses were performed for men and women.

RESULTS

Perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) were negatively associated with both atopic eczema (OR per IQR increase 0.58 (95% CI 0.37-0.90) for PFOA and 0.56 (0.32-0.95) for PFOS) and contact dermatitis (0.37 (0.16-0.85) for PFOA and 0.33 (0.11-0.94) for PFOS). Perfluoroundecanoate (PFUnDA) was negatively associated with pollen, dust, and mite allergy (0.62 (0.43-0.89)). BKMR modelling showed a negative tendency in the overall effect of PFAS mixture on immune-health outcomes. Based on the stratified analysis, sex was suggested to be an effect modifier in the association of PFOS and atopic eczema.

CONCLUSION

Our results contribute to the body of literature that observes the immunosuppressive effect of PFAS exposure during eczemas and allergies, both for PFASs individually and as a mixture.

Association of sleep duration with underweight and obesity in older adults: A cross-sectional study of the Chinese longitudinal healthy longevity survey

OBJECTIVES

Underweight and obesity are two of the main health concerns as they are associated with adverse health outcomes and nutrition disorders. This study determined the association of sleep duration with both underweight and obesity in Chinese older adults.

METHODS

This cross-sectional secondary data analysis was conducted using data from the 2018 wave of the Chinese Longitudinal Healthy Longevity Survey. There were 13 917 participants aged 65 and above in the analysis. Body mass index (BMI) was categorized into underweight, normal weight and overweight, and obesity. Self-reported sleep duration was divided into short, normal, and long sleep duration. Logistic regression models were used to examine the association of sleep duration with underweight and obesity.

RESULTS

The prevalence of underweight was 16.7% and the prevalence of obesity was 8.0% in Chinese older adults aged 65 and older. Compared to the normal sleep duration group, the short sleep duration group had a higher incidence of underweight (AOR = 1.29, 95% CI: 1.01-1.65), and the long sleep duration group showed a higher incidence of obesity (AOR = 1.57, 95% CI: 1.07-2.30) in older men. A greater incidence of underweight was found in the short sleep duration group (AOR = 1.19, 95% CI: 1.02-1.40) in old-old adults after adjusting for covariates.

CONCLUSIONS

Short sleep duration is associated with being underweight and long sleep duration is linked with obesity in older men. Short sleep duration is also a risk factor for the underweight of old-old adults.

Different patterns of changes in free 25-hydroxyvitamin D concentrations during intermittent fasting among meat eaters and non-meat eaters and correlations with amino acid intake

We prospectively assessed changes in free 25-hydroxyvitamin D [25(OH)D] and vitamin D binding protein (VDBP) among overweight adults who followed a pescatarian Orthodox intermittent fasting regimen (n = 59) and controls who followed a low-fat 12:12 diet (n = 46). Total and free 25(OH)D, parathyroid hormone, VDBP, anthropometric data, and amino acid intake were evaluated in both groups at three time points: at baseline, 7 weeks after diet implementation, and 5 weeks after participants returned to their usual eating habits (12 weeks from baseline). An increase in amino acid intake between baseline and 12 weeks was independently correlated with higher free 25(OH)D values at 12 weeks for both groups. Our findings suggest that diet can affect free 25(OH)D concentrations, through variations in amino acid intake, independently of exposure to sunlight, providing novel mechanistic insights into the future planning of vitamin D supplementation strategies. However, this hypothesis needs to be tested in larger studies.

Associations of Young Adult Intelligence, Education, Height, and Body Mass Index with Subsequent Risk of Parkinson's Disease and Survival: A Danish Cohort Study

BACKGROUND

The underlying disease mechanisms of Parkinson's disease (PD) are still unknown and knowledge about risk and prognostic factors is sparse.

OBJECTIVE

To examine the association between intelligence, education, body height, and body mass index (BMI) in young adulthood and risk of PD and subsequent survival.

METHODS

In total, 656,751 men born 1939-1959 with information from conscription examinations around age 19 years were followed for PD and mortality from 1977-2018 in Danish registries. Cox proportional hazard regression was used to conduct the analyses.

RESULTS

During follow-up, 5,264 (0.8%) men were diagnosed with PD. Higher intelligence, education, and body height conferred a higher hazard of PD, independent of age at disease onset. BMI above compared to below the mean (22.8 kg/m2) was associated with slightly higher hazard of late-onset PD (>60 years). During follow-up, 2,125 (40.5%) men with PD died, corresponding to a 2.55 (95% confidence interval:2.44-2.66) times higher mortality compared to men without PD. Intelligence was inversely associated with mortality in men with and without PD. Higher education and body height were also inversely associated with mortality in men without PD, whereas the estimates were less pronounced and imprecisely estimated for men with PD. Having an obese BMI was associated with higher mortality in men with PD.

CONCLUSION

Intelligence, education, and body height in young adulthood are positively associated with risk of PD later in life among men. BMI above the mean only confer a higher risk for late-onset PD. For men diagnosed with PD, high intelligence is the only early life indicator associated with better survival, whereas obese BMI predicts poorer survival.

Body mass index in young adulthood and risk of subsequent dementia at different levels of intelligence and education in Danish men

The risk of dementia seems to be established already early in life, which leads to the question if overweight early in life is an important risk factor for dementia as it appears to be later in life. We examined the association between body mass index (BMI) at entry to adult life and subsequent risk of dementia in men and assessed whether the relationship differed by levels of intelligence and education. The study population consisted of 377,598 Danish men born 1939-1959 with measures of height, weight, intelligence test score (ITS), and educational level (EL) at conscript board examinations around the age of 19 years. Dementia outcomes were obtained from National Patient and Prescription Registries between 1969 and 2016. The association between BMI and dementia was analysed using Cox proportional hazard regression including interactions between BMI and ITS and EL, respectively. During the follow-up through age 77 years, 6144 (1.6%) developed dementia. The frequency was highest in men with lowest BMI, lowest ITS and lowest EL. Young adult BMI below the mean of 21.8 kg/m² was inversely associated with subsequent dementia, whereas there was no association with higher levels of BMI. Adjustment for young adult ITS and EL attenuated the risk estimates slightly, and interaction analyses showed that the shape of the association between BMI and dementia was unaffected by the levels of ITS and EL. Regardless of levels of ITS and EL, young adult BMI below the mean is inversely associated with subsequent dementia, whereas there is no association with higher levels of BMI.

Body mass index and height in relation to type 2 diabetes by levels of intelligence and education in a large cohort of Danish men

Socioeconomic status (SES) is inversely associated with risks of type 2 diabetes (T2D). We investigated if young men's cognitive function, measured by intelligence test scores and educational level, as determinants of SES modified associations between body mass index (BMI) and height with the risk of T2D. 369 989 young men from the Danish Conscription Database born between 1939 and 1959 with information on measured height, weight, intelligence test scores, and education were linked to the Danish National Patient Register. During follow-up from 1977 through 2015, T2D was recorded in 32 188 men. Hazard ratios (HR) and 95% confidence intervals (95% CI) were estimated by Cox regressions. BMIs below-average (z-scores ≤ 0) were not related to risks of T2D. For BMIs above-average (z-scores > 0), positive associations between BMI and T2D were slightly stronger among men with higher intelligence test scores or longer educations than among men with lower levels of these factors (p_interaction-values < 0.004). Irrespective of BMI, incidence rates of T2D were higher among men with low levels of intelligence test score and education. Height was inversely associated with T2D (per z-score, HR = 0.96 (95% CI 0.95-0.97) and the association did not vary by intelligence test scores or education (all p_interaction-values > 0.59). While below-average BMI was not associated with T2D risk, above-average BMIs were and these association were stronger among men with high cognitive function. Nevertheless, T2D risk was higher at lower levels of cognitive function throughout the range of BMI. Height was inversely associated with T2D and it was not modified by cognitive function.

Which body shape dimensions and sizes predict depression?

BACKGROUND

Obesity is associated with depression, but a common measure of obesity, body mass index (BMI), combines height and weight. Consequently, which body shape dimensions and sizes are most relevant to depression is unclear.

METHOD

Data were analyzed from the National Health and Nutrition Examination Survey years 2007-2016, focusing on adults age 20 and older who were not pregnant. In this nationally-representative sample (N = 23,739), relations of depressive symptoms with body shape variables were tested, controlling for age, gender, ethnicity, and socioeconomic status.

RESULTS

Body weight and BMI, but not standing height, predicted depressive symptoms. Adults with relatively high body weight or BMI (roughly the top 30-40% of women or 10% of men) had substantively elevated depressive symptoms (d ≥ 0.20) within genders. BMI ranges predicting elevated depressive symptoms among women (BMI ≥ 30) and men (BMI ≥ 36) were higher than standard overweight and obesity definitions, respectively.

LIMITATIONS

This observational study was cross-sectional. Future longitudinal and experimental research is needed to clarify potential causal relations between body weight and depression. Other body shape variables may also predict depression.

CONCLUSIONS

Body weight but not height predicted concurrent risk for depressive symptomatology in the United States. Future research should test whether assessment focused on body weight not adjusted for height, as in BMI, improves depression prevention and treatment.

Body mass index in young men and risk of inflammatory bowel disease through adult life: A population-based Danish cohort study

Body mass index (BMI) is associated with increased future risk of inflammatory bowel disease(IBD) particularly Crohn’s disease(CD), where associations with high and low BMI have been observed. Most studies are based on adult women. We aimed to explore the impact of BMI in men entering adult life on their long-term risk of developing IBD. A total of 377,957 men born during 1939–1959, with BMI measured at draft boards at mean age 19, were followed from 1977, or time of examination, to end of 2015. Risk of IBD was assessed using Cox regression. During 13 million person-years of follow-up, 1,523 developed CD and 3,323 UC. Using normal weight as reference, for CD the following HRs were observed: BMI < 18.5, 1.35; 95% CI, 1.12–1.62, BMI 25–29.9; 0.83; 95% CI, 0.68–1.02. and BMI > 30 1.20; 95% CI, 0.75–1.90). The increased risk of CD in underweight was maintained up until age 60 not explained by known effects of smoking. For UC, minor inverse associations were observed. Restricted cubic splines revealed a U-shape association between BMI and CD, but not UC. Low BMI of men entering adult life is associated with an increased incidence of CD and UC up to 40 years later.

Identification of outliers and positive deviants for healthcare improvement: looking for high performers in hypoglycemia safety in patients with diabetes

Background

The study objectives were to determine: (1) how statistical outliers exhibiting low rates of diabetes overtreatment performed on a reciprocal measure – rates of diabetes undertreatment; and (2) the impact of different criteria on high performing outlier status.

Methods

The design was serial cross-sectional, using yearly Veterans Health Administration (VHA) administrative data (2009–2013). Our primary outcome measure was facility rate of HbA1c overtreatment of diabetes in patients at risk for hypoglycemia. Outlier status was assessed by using two approaches: calculating a facility outlier value within year, comparator group, and A1c threshold while incorporating at risk population sizes; and examining standardized model residuals across year and A1c threshold. Facilities with outlier values in the lowest decile for all years of data using more than one threshold and comparator or with time-averaged model residuals in the lowest decile for all A1c thresholds were considered high performing outliers.

Results

Using outlier values, three of the 27 high performers from 2009 were also identified in 2010–2013 and considered outliers. There was only modest overlap between facilities identified as top performers based on three thresholds: A1c < 6%, A1c < 6.5%, and A1c < 7%. There was little effect of facility complexity or regional Veterans Integrated Service Networks (VISNs) on outlier identification. Consistent high performing facilities for overtreatment had higher rates of undertreatment (A1c > 9%) than VA average in the population of patients at high risk for hypoglycemia.

Conclusions

Statistical identification of positive deviants for diabetes overtreatment was dependent upon the specific measures and approaches used. Moreover, because two facilities may arrive at the same results via very different pathways, it is important to consider that a “best” practice may actually reflect a separate “worst” practice.