Relationship Between Socioeconomic Status and the Prevalence of Underweight, Overweight or Obesity in a General Japanese Population: NIPPON DATA2010

The impact of poverty and socioeconomic status on brain, behaviour, and development: a unified framework

In this article, we, for the first time, provide a comprehensive overview and unified framework of the impact of poverty and low socioeconomic status (SES) on the brain and behaviour. While there are many studies on the impact of low SES on the brain (including cortex, hippocampus, amygdala, and even neurotransmitters) and behaviours (including educational attainment, language development, development of psychopathological disorders), prior studies did not integrate behavioural, educational, and neural findings in one framework. Here, we argue that the impact of poverty and low SES on the brain and behaviour are interrelated. Specifically, based on prior studies, due to a lack of resources, poverty and low SES are associated with poor nutrition, high levels of stress in caregivers and their children, and exposure to socio-environmental hazards. These psychological and physical injuries impact the normal development of several brain areas and neurotransmitters. Impaired functioning of the amygdala can lead to the development of psychopathological disorders, while impaired hippocampus and cortex functions are associated with a delay in learning and language development as well as poor academic performance. This in turn perpetuates poverty in children, leading to a vicious cycle of poverty and psychological/physical impairments. In addition to providing economic aid to economically disadvantaged families, interventions should aim to tackle neural abnormalities caused by poverty and low SES in early childhood. Importantly, acknowledging brain abnormalities due to poverty in early childhood can help increase economic equity. In the current study, we provide a comprehensive list of future studies to help understand the impact of poverty on the brain.

Maternal pre-pregnancy body mass index and related factors: A cross-sectional analysis from the Japan Environment and Children's Study

Socioeconomic status and smoking are reportedly associated with underweight and obesity; however, their associations among pregnant women are unknown. This study aimed to investigate whether socioeconomic factors, namely educational attainment, household income, marital status, and employment status, were associated with pre-pregnancy body mass index (BMI) categories, including severe-moderate underweight (BMI ≤ 16.9 kg/m2), mild underweight (BMI, 17.0-18.4 kg/m2), overweight (BMI, 25.0-29.9 kg/m2), and obese (BMI ≥ 30.0 kg/m2) among Japanese pregnant women using data from the Japan Environment and Children's Study (JECS). In total, pregnant women were included 96,751. Age- and parity-adjusted multivariable multinomial logistic regression analyses assessed socioeconomic factors and smoking associations with falling within abnormal BMI categories (normal BMI as the reference group). Lower education and lower household were associated with overweight and obesity, and, especially, lowest education and household income had relatively higher point estimate relative ratios (RRs) of 3.97 and 2.84, respectively. Regarding the risks for underweight, however, only junior high school education had a significantly higher RR for severely to moderately underweight. Regarding occupational status, homemakers or the unemployed had a higher RR for severe-moderate underweight, overweight, and obesity. Unmarried, divorced, or bereaved women had significantly higher RRs for mildly underweight status. Quitting smoking early in pregnancy/still smoking had higher RRs for all four not having normal BMI outcomes; however, quitting smoking before pregnancy had a higher RR only for obese individuals. Lower educational attainment and smoking are essential intervention targets for obesity and severe-moderate underweight prevention in younger women. Lower household income is also a necessary target for obesity.

Trends of gastric cancer burdens attributable to risk factors in China from 2000 to 2050

Background

The incidence of gastric cancer (GC) decreased in past decades, which was thought largely attributable to risk factors control, yet China still accounts for 44% of global GC burdens. We aimed to estimate changing trajectories of proportions of GC burdens attributable to modifiable risk factors from 2000 to 2050 in China, to inform future targeted preventive strategies.

Methods

The incidence and new cases of GC were predicted to 2050 using Bayesian age-period-cohort model based on incidence data by anatomical subsites drawn from 682 cancer registries from National Central Cancer Registry. Population attributable fractions (PAFs) were calculated based on prevalence of risk factors and relative risks with GC. Temporal trends of PAFs were described by sex and categories of risk factors using joinpoint analysis.

Findings

We observed declining trends of PAFs of Helicobacter pylori (H. pylori) infection, smoking, pickled vegetable and alcohol consumption, but increasing trends of PAFs of unhealthy body mass index and diabetes for GC in China. The combined PAFs of these risk factors were estimated to decrease by 10.57% from 2000 to 2050 for GC. We estimated there will be 279,707 GC (122,796 cardia gastric cancer [CGC] and 156,911 non-cardia gastric cancer [NCGC]) cases in 2050. Out of these cases, 70.18% of GC cases could be attributable to modifiable risk factors, while H. pylori infection was predicted to be responsible for 40.7% of CGC and 62.1% of NCGC cases in 2050.

Interpretation

More than half of GC remained attributable to modifiable risk factors in China. Continued effective strategies on risk factors control are needed to reduce the burden of this highly life-threatening cancer in future.

Funding

Beijing Nova Program (No. Z201100006820069), CAMS Innovation Fund for Medical Sciences (CIFMS, grant No. 2021-I2M-1-023), CAMS Innovation Fund for Medical Sciences (CIFMS, grant No. 2021-I2M-1-010), Talent Incentive Program of Cancer Hospital Chinese Academy of Medical Sciences (Hope Star).

Obesity and hypertension from a public health perspective in a small remote island of Okinawa, Japan

This study investigated the relationship between obesity and hypertension from a public health perspective in a small remote island of Okinawa where obesity is prevalent. A cross-sectional study was conducted in 456 residents aged ≥18 years in Yonaguni island who underwent an annual health check-up and the Yonaguni dietary survey in 2022. Each participant responded to our original questionnaire and provided further dietary survey data via the Yonaguni municipal government. The odds ratio for hypertension was calculated in the obese group, using a logistic regression model with the non-obese group serving as the reference. Hypertension was defined as a systolic blood pressure ≥140 mmHg, a diastolic blood pressure ≥90 mmHg measured on an automated sphygmomanometer, and/or taking anti-hypertensive agents, while obesity was defined as a body mass index ≥25 kg/m2. The proportion of hypertension associated with obesity among all hypertensive subjects was calculated. The prevalence of obesity and hypertension was 54.3% and 49.0% in the 208 male subjects and 32.3% and 43.6% in the 248 female subjects, respectively. The odds ratio for hypertension in the obese group was 3.73 (95% confidence interval, 1.93-7.20) for men and 4.13 (2.06-8.29) for women after adjusting for age, alcohol drinking habit, behavior for lowering salt intake, and smoking habit. Hypertension in 49.5% (95% confidence interval, 29.4%-63.9%) of males and 37.9% (22.6%-50.2%) of females was associated with obesity in this island. Some areas of Japan could be urgently required to address obesity for preventing cardiovascular disease. A community-based, cross-sectional study in 456 residents aged ≥18 years in Yonaguni island, Okinawa prefecture, Japan.

The Impact of Pretreatment Low Body Mass Index on Cause-Specific Mortality in Patients with Squamous Cell Carcinoma of the Oral Cavity

The association between the pretreatment body mass index (BMI) and oral squamous cell carcinoma (SCC) outcomes is controversial. We aimed to examine the association between BMI and cause-specific mortality due to cancer of the oral cavity and patterns of failure that correlate with increased mortality. We enrolled 2,023 East Asian patients in this multicenter cohort study. We used the cumulative incidence competing risks method and the Fine-Gray model to analyze factors associated with cause-specific mortality, local recurrence, regional metastasis, and distant metastasis as first events. The median follow-up period was 62 mo. The 5-year cause-specific mortality for patients with underweight was 25.7%, which was significantly higher than that for patients with normal weight (12.7%, P < 0.0001). The multivariate model revealed that underweight was an independent risk factor for cause-specific mortality and regional metastasis (P < 0.05). Moreover, patients with underweight displayed a 51% and 55% increased risk of cause-specific mortality and regional metastasis, respectively, compared with their normal weight counterparts. Local recurrence was not associated with the BMI categories; however, the incidence of distant metastasis inversely decreased with BMI value. In summary, being underweight at diagnosis should be considered a high-risk mortality factor for oral SCC.

Longitudinal patterns and sociodemographic profiles of health-related behaviour clustering among middle-aged and older adults in China and Japan

Given inevitable age-related decreases in physical or mental capacity, studies on health-related behaviour (HRB) clustering in older people provide an opportunity to reduce health-care costs and promote healthy ageing. This study explores the clustering of HRBs and transition probabilities of cluster memberships over time, and compares sociodemographic characteristics of these clusters among Chinese and Japanese middle-aged and older adults. Using the China Health and Retirement Longitudinal Study (CHARLS) from 2011 to 2015 (N = 19614) and the Japanese Study of Ageing and Retirement (JSTAR) from 2007 to 2011 (N = 7,080), Latent Transition Analysis was applied to investigate the clustering and change in clustering memberships of smoking, alcohol consumption, physical activity and body mass index. Multivariate logistic regression was used to explore the sociodemographic characteristics of these longitudinal HRB cluster members. We identified four common clusters in CHARLS and JSTAR: ‘smoking’, ‘overweight or obese’, ‘healthy lifestyle’ and ‘current smoking with drinking’, and an additional cluster named ‘ex-smoking with drinking’ in JSTAR. Although HRB cluster members were largely stable in both cohorts, participants in China tended to move towards an unhealthy lifestyle, while participants in Japan did the opposite. We also found that participants who smoked and drank were more likely to be male, younger, less educated and unmarried in both cohorts, but the overweight or obese participants were female, urban and higher income in CHARLS but not JSTAR. Our study not only contributes to the knowledge of longitudinal changes in health-related behavioural clustering patterns in an Asian elderly population, but may also facilitate the design of targeted multi-behavioural interventions to promote healthy lifestyles among older people in both countries.

Early childhood exposure to maternal smoking and obesity: A nationwide longitudinal survey in Japan

Involuntary exposure to tobacco smoke is suspected to be one of the risks factors that are associated with obesity in children. The purpose of this study was to examine the relationship between early childhood exposure to tobacco smoke and the risk of obesity and overweight in Japan. This study utilized a nationwide, population-based longitudinal survey. The participants were restricted to 32 081 children who had available information on maternal smoking history as well as childhood height and weight. We conducted a binomial log-linear regression analysis with children of non-smoking mothers as the reference group. The children with mothers who were smokers had a higher risk of developing obesity or being overweight compared to the children with mothers who were nonsmokers. The risk ratios were 1.20 (95% confidence interval [CI]: 1.09-1.32) for overweight and 1.17 (95% CI: 0.95-1.44) for obesity. Early exposure to maternal smoking increases the risk of being overweight and having obesity during childhood. The increased risk is more pronounced among children with mothers, smoked heavily, or parents, who were smokers.

Regional Differences in the Prevalence of Atopic Dermatitis among Schoolchildren in Japan and Its Associated Factors from 2006 to 2018

The trends in the prevalence of atopic dermatitis for each prefecture over recent years have not been investigated in Japan, and no studies investigating the factors associated with the prevalence using nationwide data have been conducted. We investigated the trends in the prevalence of atopic dermatitis among schoolchildren for each prefecture in Japan from 2006 to 2018 and identified the factors associated with regional differences in prevalence. The data on the atopic dermatitis prevalence in schoolchildren aged 6–17 years were collected as part of the School Health Statistics Research. The demographic, socioeconomic, medical, and environmental characteristics of the prefectures were examined for possible associations with the prevalence. The age-standardized prevalence rates of atopic dermatitis were calculated separately for boys and girls and by prefecture and year. We examined the associations between the age-standardized prevalence rates and prefectural characteristics using an ecological study. The age-standardized prevalence rates of atopic dermatitis tended to be stable for Japan as a whole, whereas the trend in the age-standardized prevalence rates differed across prefectures. In the regression analysis, the year was negatively associated and the number of medical clinics per 100,000 persons was positively associated with the age-standardized prevalence in girls. The taxable income per capita was positively associated with the age-standardized prevalence both in boys and in girls.

Analysis of regional differences in the amount of hypnotic and anxiolytic prescriptions in Japan using nationwide claims data

BACKGROUND

In Japan, there has been no investigation of regional differences in the number or amount of prescriptions of anxiolytics or hypnotics. Attributes related to the high amount of prescriptions for these drugs are unknown. We investigated recent trends and regional differences in the amount of prescriptions of hypnotics and anxiolytics in Japan and identified factors associated with these regional differences.

METHODS

The National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB) Open data from 2015 to 2018 were used. We calculated diazepam-equivalent doses (mg) for each drug and the total amount of prescriptions per capita for hypnotics and anxiolytics by sex and age. In addition, we calculated the standardized claim ratio (SCR) of the amount of prescriptions by prefecture. We investigated factors associated with regional differences in the SCRs of hypnotics and anxiolytics using the prefectures' medical, socioeconomic, and physical characteristics by an ecological study using a linear mixed-effects model.

RESULTS

The amount of prescriptions of hypnotics and anxiolytics, specifically, the amount of prescriptions of benzodiazepine receptor agonists (BZRAs), decreased in many of the adult age groups from 2015 to 2018. The regression analysis revealed that the number of medical clinics per capita, the number of public assistance recipients per capita, the proportion of persons whose HbA1c ≥ 6.5%, and the proportion of persons whose BMI ≥25 kg/m2 were positively and significantly associated with the SCR of hypnosis. In contrast, the number of public assistance recipients per capita and the proportion of persons whose BMI ≥25 kg/m2 were positively and significantly associated with the SCR of anxiolytics.

CONCLUSIONS

Factors associated with prescription amount of hypnotics and anxiolytics were revealed in this study, and a further study is needed for investigating causal relationships between the prescriptions amount and the associated factors using individual data.

Socioeconomic Predictors of Diabetes Mortality in Japan: An Ecological Study Using Municipality-specific Data

Objectives

The aim of this study was to examine the geographic distribution of diabetes mortality in Japan and identify socioeconomic factors affecting differences in municipality-specific diabetes mortality.

Methods

Diabetes mortality data by year and municipality from 2013 to 2017 were extracted from Japanese Vital Statistics, and the socioeconomic characteristics of municipalities were obtained from government statistics. We calculated the standardized mortality ratio (SMR) of diabetes for each municipality using the empirical Bayes method and represented geographic differences in SMRs in a map of Japan. Multiple linear regression was conducted to identify the socioeconomic factors affecting differences in SMR. Statistically significant socioeconomic factors were further assessed by calculating the relative risk of mortality of quintiles of municipalities classified according to the degree of each socioeconomic factor using Poisson regression analysis.

Results

The geographic distribution of diabetes mortality differed by gender. Of the municipality-specific socioeconomic factors, high rates of single-person households and unemployment and a high number of hospital beds were associated with a high SMR for men. High rates of fatherless households and blue-collar workers were associated with a high SMR for women, while high taxable income per-capita income and total population were associated with low SMR for women. Quintile analysis revealed a complex relationship between taxable income and mortality for women. The mortality risk of quintiles with the highest and lowest taxable per-capita income was significantly lower than that of the middle-income quintile.

Conclusions

Socioeconomic factors of municipalities in Japan were found to affect geographic differences in diabetes mortality.

Living alone and prediction of weight gain and overweight/obesity in university students: a retrospective cohort study

To assess the clinical impact of living alone on weight gain in university students. Participants: This retrospective cohort study included 17540 male and 8854 female university students admitted to a national university in Japan. Methods: An association between living arrangement and the incidence of weight gain ≥10% and overweight/obesity (body mass index (BMI) ≥25 kg/m²) was assessed using multivariable-adjusted Poisson regression models. Results: Weight gain was observed in 1889 (10.8%) male and 1516 (17.1%) female students during 3.0 and 2.9 years of the mean observational period, respectively. Living alone was identified as a significant predictor of weight gain (adjusted incidence rate ratio of living alone vs. living with family: 1.24 [1.13-1.36] and 1.76 [1.58-1.95] in male and female students, respectively) and was also as a predictor of overweight/obesity. Conclusions: University students living alone were at a significantly higher risk of weight gain and overweight/obesity than those living with family.

Analysis of the regional difference in the number of multi-drug prescriptions and its predictors in Japan, 2015-2018

Objective

Polypharmacy and multi-drug prescription are major public health problems in Japan, but only a few studies have investigated the regional differences. By revealing regional differences in the multi-drug prescriptions, we can infer regions with high rates of multimorbidity or inappropriate prescribing. This study revealed regional differences in multi-drug prescriptions (the number of simultaneous prescriptions of seven or more internal medicines) and investigated the factors affecting the difference using the National Database of Health Insurance Claims and Specific Health Checkups of Japan data.

Results

The standardized claim ratio (SCR) of the number of multi-drug prescriptions, which corrected the difference in sex and age distribution of prefectures, varied depending on prefectures. A panel data analysis investigating the association between the SCR and explanatory variables (Medical institutions, socioeconomic factors, and physical characteristics of people in prefectures) revealed that the number of public assistance recipients per 1,000 persons was positively and significantly associated with the SCR (Standardized partial regression coefficient = 0.244, p-value = 0.038). In conclusion, regional differences in the number of the multi-drug prescriptions were revealed in Japan, suggesting that public assistance recipients tend to experience multi-drug prescriptions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-021-05787-2.

An Association between Maternal Occupations and Low Birth Weight Infants in Japan from 1995 to 2015

Differences in low birth weight rate depending on maternal socioeconomic characteristics have not yet been demonstrated using the Vital Statistics in Japan; therefore, this study aimed to investigate these differences according to maternal occupations. “Report of Vital Statistics: Occupational and Industrial Aspects” and the Vital Statistics in Japan were used every five years from 1995 to 2015. Nine types of occupations were compared. The low birth weight rate was calculated according to maternal occupations and year. Also, the standardized low birth weight ratio was obtained by dividing the number of low-birth-weight infants for each maternal occupation by an expected number of low birth weight infants. The standardized low birth weight ratio for manual workers was the highest among all occupations from 2000 to 2015, and it was significantly higher than one throughout the years. The ratio for clerical workers was also significantly higher than one from 1995 to 2010. Whereas, the ratio for farmers was significantly lower than one in most of the years. It was suggested that health guidance and prenatal care are particularly needed for manual workers, and a study investigating the differences in prenatal characteristics among maternal occupations is necessary for finding a reason for disparity.

Higher Socioeconomic Status is Associated with Improved Outcomes After Obesity Surgery Among Women in Germany

Background

Low socioeconomic status (SES) is associated with an increased prevalence of obesity. It is unknown whether SES influences the outcome after bariatric surgery in Germany. Therefore, the aim of our study was to investigate whether the SES is linked with an inferior outcome after bariatric surgery.

Methods

We included all patients who underwent bariatric surgery in our university hospital from 2012–2014. Net income was estimated by matching the zip codes of patient residency with the region-specific purchasing power index. We analyzed the relationship between SES, weight loss and remission of comorbidities.

Results

We included 559 patients in this study and detected a mean 5-year percentage excess weight loss (%EWL) of 52.3%. We detected a significantly lower initial body mass index (BMI) and weight in patients with a higher income. One year after surgery, we did not find a significant difference. Further analysis revealed that only women with a higher income had a significantly lower BMI and weight 3 and 5 years after surgery.

Conclusions

Bariatric surgery is beneficial for all patients regardless of income. Furthermore, we demonstrated that women with high SES have a better outcome after bariatric surgery.

Machine learning-based image analysis for accelerating the diagnosis of complicated preneoplastic and neoplastic ductal lesions in breast biopsy tissues

PURPOSE

Diagnosis of breast preneoplastic and neoplastic lesions is difficult due to their similar morphology in breast biopsy specimens. To diagnose these lesions, pathologists perform immunohistochemical analysis and consult with expert breast pathologists. These additional examinations are time-consuming and expensive. Artificial intelligence (AI)-based image analysis has recently improved, and may help in ordinal pathological diagnosis. Here, we showed the significance of machine learning-based image analysis of breast preneoplastic and neoplastic lesions for facilitating high-throughput diagnosis.

METHODS

Images were obtained from normal mammary glands, hyperplastic lesions, preneoplastic lesions and neoplastic lesions, such as usual ductal hyperplasia (UDH), columnar cell lesion (CCL), ductal carcinoma in situ (DCIS), and DCIS with comedo necrosis (comedo DCIS) in breast biopsy specimens. The original enhanced convoluted neural network (CNN) system was used for analyzing the pathological images.

RESULTS

The AI-based image analysis provided the following area under the curve values (AUC): normal lesion versus DCIS, 0.9902; DCIS versus comedo DCIS, 0.9942; normal lesion versus CCL, 0.9786; and UDH versus DCIS, 1.000. Multiple comparison analysis showed precision and recall scores similar to those of single comparison analysis. Based on the gradient-weighted class activation mapping (Grad-CAM) used to visualize the important regions reflecting the result of CNN analysis, the ratio of stromal tissue in the whole weighted area was significantly higher in UDH and CCL than that in DCIS.

CONCLUSIONS

These analyses may provide a more accurate and rapid pathological diagnosis of patients. Moreover, Grad-CAM identifies uncharted important histological characteristics for newer pathological findings and targets of research for understanding diseases.

Sex difference in the association of obesity with personal or social background among urban residents in Japan

The development of obesity is influenced by genetic and environmental factors and is associated with a variety of health problems. To gain insight into environmental factors that contribute to obesity, we analyzed the relation of personal or social background to obesity in men and women separately with the use of data from a community-based questionnaire survey of 5425 residents aged 20 to 64 years of Kobe, a representative large city in Japan. Obesity and normal weight were defined as a body mass index (BMI) of ≥25 and of ≥ 18.5 and < 25 kg/m2, respectively, according to the diagnostic criteria of the Japan Society for the Study of Obesity. The personal or social background factors examined included marital status, family structure, employment, household income, residence type, welfare enrollment, economic conditions of current life, educational level, extracurricular activity in school, living conditions at 15 years of age, and childhood adversity. We found that the prevalence of obesity was 27.2% and 10.6% in men and women, respectively. Among women, unmarried status, a low household income, welfare enrollment, difficult current economic conditions, a low educational level, and childhood adversity were associated with obesity, whereas none of the personal or social background factors examined were associated with obesity in men. Our results suggest that the development of obesity in women is strongly influenced by personal or social background, and such factors should be taken into consideration in the management of this condition in women.

Can Daily Walking Alone Reduce Pneumonia-Related Mortality among Older People?

Pneumonia-related mortality is expected to increase in aging societies. This prospective cohort study examined whether daily walking (1 hour/day) could reduce pneumonia-related mortality among older people who lacked other exercise habits. We analysed data from Japanese Specific Health Checkup across 82 municipalities in 7 prefectures among participants aged ≥65 years who participated in daily walking but did not regularly engage in other forms of exercise (n = 132,448). Information on walking habits and health-related indicators was assessed at a baseline survey conducted between 2008 and 2014. Pneumonia-related and all-cause mortality were followed for a median of 3.4 years. We performed a competing risk model with propensity score matching to evaluate the association between daily walking habits and pneumonia-related mortality. Our propensity-matched analysis revealed a significant association between daily walking and pneumonia-related mortality among older people who lacked other exercise habits, such that the sub-hazard ratio and 95% confidence intervals were 0.58 (0.39, 0.86). This study extends the findings of previous research on the effects of exercise on pneumonia by demonstrating that daily walking alone is sufficient to reduce pneumonia-related mortality among older people who do not regularly engage in other exercise habits.

Dementia risk by combinations of metabolic diseases and body mass index: Japan Gerontological Evaluation Study Cohort Study

AIMS/INTRODUCTION

To compare the dementia risk associated with pre-existing diabetes, hypertension, dyslipidemia, obesity (body mass index [BMI] ≥25 kg/m2 ) and underweight (BMI <18.5 kg/m2 ) among older adults. We also explored the dementia risk associated with combinations of metabolic diseases and BMI.

MATERIALS AND METHODS

We used data from the Japan Gerontological Evaluation Study. Participants completed a health checkup in 2010 and were followed for 5.8 years on average. Dementia was measured by municipal long-term care insurance registration. Diabetes, hypertension, dyslipidemia, obesity and underweight were diagnosed by medication use or health examination results. We calculated the incidence of dementia and adjusted hazard ratios (HRs).

RESULTS

Among 3,696 participating older adults, 338 developed dementia. Adjusted HRs (95% confidence intervals) in men and women (reference: those without corresponding disease of normal weight) were as follows: 2.22 (1.26-3.90) and 2.00 (1.07-3.74) for diabetes; 0.56 (0.29-1.10) and 1.05 (0.64-1.71) for hypertension; 1.30 (0.87-1.94) and 0.73 (0.49-1.08) for dyslipidemia; 0.73 (0.42-1.28) and 0.82 (0.49-1.37) for BMI of 25-29.9 kg/m2 ; and 1.04 (0.51-2.10) and 1.72 (1.05-2.81) for underweight. Dementia risk was significantly higher in underweight men with dyslipidemia (HR 4.15, 95% CI 1.79-9.63) compared with normal-weight men without dyslipidemia, and in underweight women with hypertension (HR 3.79, 1.55-9.28) compared with normal-weight women without hypertension. Dementia incidence was highest among underweight older adults with hypertension followed by dyslipidemia.

CONCLUSIONS

Among Japanese older adults, underweight and prevalent diabetes are risk factors for developing dementia. Lower BMI is also associated with a higher incidence of dementia.

Prevalence of breast cancer-related risk factors in underweight premenopausal women: the Korea National Health and Nutrition Examination Survey IV-VI

PURPOSE

This study aimed to examine the prevalence and trends of breast cancer-related risk factors and characteristics in premenopausal underweight Korean women according to birth year cohort.

METHODS

Socioeconomic and breast cancer-related risk factors were investigated in 13,415 premenopausal women using nationwide cross-sectional surveys performed between 2007 and 2015. Underweight was defined as body mass index < 18.5 kg/m². Multivariable models were created using complex sample procedures.

RESULTS

Underweight women comprised 9.5% of the sample. Compared with those who were obese or of normal weight, underweight women were characterized by younger age, higher rate of metropolitan residence, higher economic status, more education, higher rates of non-manual employment and unmarried status, lower rate of early menarche, higher rates of nulliparity, lower parity, alcohol consumption, and never having breastfed, and lower levels of high physical activity. Multivariable analysis showed that underweight women had a significantly lower rate of early menarche, lower parity, higher nulliparity, older age at first delivery, and lower levels of high physical activity compared to premenopausal women with normal weight. These trends were more apparent among women born in recent years.

CONCLUSIONS

Underweight Korean premenopausal women exhibit distinctive features associated with an increased risk of breast cancer, except for a lower rate of early menarche. These associations were prominent in recent generations. Assessment of the association between underweight and premenopausal breast cancer risk should focus on promoting healthy lifestyles to reduce breast cancer risk.