Trends and Inequalities in Overall and Abdominal Obesity by Sociodemographic Factors in Korean Adults, 1998-2018

Associations of Ultra-Processed Food Intake with Body Fat and Skeletal Muscle Mass by Sociodemographic Factors

BACKGRUOUND

The effects of excessive ultra-processed food (UPF) consumption on body composition measures or sociodemographic disparities are understudied in Korea. We aimed to investigate the association of UPF intake with percent body fat (PBF) and percent appendicular skeletal muscle mass (PASM) by sociodemographic status in adults.

METHODS

This study used data from the Korea National Health and Nutrition Examination Survey 2008-2011 (n=11,123 aged ≥40 years). We used a NOVA system to classify all foods reported in a 24-hour dietary recall, and the percentage of energy intake (%kcal) from UPFs was estimated. PBF and PASM were measured by dual-energy X-ray absorptiometry. Tertile (T) 3 of PBF indicated adiposity and T1 of PASM indicated low skeletal muscle mass, respectively. Multinomial logistic regression models were used to estimate odds ratios (OR) with 95% confidence interval (CI) after adjusting covariates.

RESULTS

UPF intake was positively associated with PBF-defined adiposity (ORper 10% increase, 1.04; 95% CI, 1.002 to 1.08) and low PASM (ORper 10% increase, 1.05; 95% CI, 1.01 to 1.09). These associations were stronger in rural residents (PBF: ORper 10% increase, 1.14; 95% CI, 1.06 to 1.23; PASM: ORper 10% increase, 1.15; 95% CI, 1.07 to 1.23) and not college graduates (PBF: ORper 10% increase, 1.06; 95% CI, 1.02 to 1.11; PASM: ORper 10% increase, 1.07; 95% CI, 1.03 to 1.12) than their counterparts.

CONCLUSION

A higher UPF intake was associated with higher adiposity and lower skeletal muscle mass among Korean adults aged 40 years and older, particularly in those from rural areas and with lower education levels.

Perceived familial financial insecurity and obesity among Korean adolescents during the COVID-19 pandemic

BACKGROUND

In high-income countries, socioeconomically disadvantaged adolescents experience a higher risk of obesity, which may have been further exacerbated during the early phase of the COVID-19 pandemic. This study aimed to investigate the association between obesity and familial financial insecurity, utilizing data on subjective household socioeconomic status (SES) and perceived family-level financial deterioration induced by COVID-19.

METHODS

We utilized data from the Korea Youth Risk Behavior Survey, a nationally representative sample of Korean adolescents, in 2020 and 2021. The independent and joint associations of two primary exposures, subjective household SES and perceived family-level financial deterioration, with obesity were assessed using multivariable logistic regression models.

RESULTS

Among 106,979 adolescents aged 12-18 years, 16.9% of boys and 9.0% of girls met the criteria for obesity. Notably, 70.5% reported experiencing COVID-19-related financial deterioration. Both subjective household SES and perceived family-level financial deterioration independently and synergistically increased the odds of obesity. A graded association was observed between obesity and lower SES and more severe financial deterioration, particularly among girls. Younger adolescents were more sensitive to household SES, whereas older adolescents were more sensitive to financial deterioration.

CONCLUSIONS

While the COVID-19 pandemic presented a unique social context, our findings highlight that financially insecure adolescents were at an increased risk of obesity during the early phase of the pandemic. This underscores the need for obesity-prevention strategies in times of macroeconomic recession to address not only the persistent influence of household SES but also the direct and indirect effects of family-level financial deterioration.

Trends in underweight and severe underweight disparities in Korean adults and older adults: a nationwide, repeated cross-sectional study

OBJECTIVES

Little is known about the disparities in underweight prevalence among the general population in high-income countries. We investigated the trends in underweight prevalence and disparities across sociodemographic groups among Korean adults and older adults.

SETTING AND PARTICIPANTS

A series of cross-sectional data on Korean national health checkups for adults aged ≥20 years were analyzed from 2005 to 2016.

MEASUREMENTS

Based on body mass index (kg/m2), underweight was graded as mild (17.0-18.49), moderate (16.0-16.9), and severe (<16.0). Underweight prevalence was compared across sociodemographic subgroups in 2015-2016. Trends in underweight disparities were examined from 2005-2006 to 2015-2016. Multivariable-adjusted odds ratios (ORs; 95% confidence intervals, CIs) were calculated using logistic regression.

RESULTS

Approximately 11-22 million adults were included in each wave. In 2015-2016, the overall prevalence of underweight was 3.6% (men 2.0%, women 5.2%); severe underweight was 0.2% (men 0.1%, women 0.3%). The prevalence of underweight varied by sex and age groups. In men, those aged ≥80 years had the highest prevalence (overall 7.33%, severe underweight 0.84%). In women, those aged 20-29 years had the highest prevalence of overall underweight (14.57%), whereas those aged ≥80 years had the highest prevalence of severe underweight (1.38%). Compared with individuals in the lowest income quartile, men in the highest income had lower ORs of overall (0.59, 95% CI 0.59-0.60) and severe underweight (0.46, 95% CI 0.44-0.48); women in the highest income quartile had a higher OR of overall (1.12, 95% CI 1.12-1.13) but a lower OR of severe underweight (0.89, 95% CI 0.86-0.92). From 2005-2006 to 2015-2016, severe underweight consistently declined in older men but remained constant in women aged ≥80 years, widening sex disparities among older adults. Severe underweight decreased or leveled off in the highest income quartile but steadily increased in the lowest quartile, worsening income disparities.

CONCLUSION

In this nationwide study, underweight was more prevalent among women, older adults aged ≥80 years, and low-income individuals. Disparities in severe underweight widened across sociodemographic subgroups over time.

Factors associated with the combination of general and abdominal obesity in middle-aged and older Korean women: a cross-sectional study

BACKGROUND

To identify factors associated with general and abdominal obesity in middle-aged and older Korean women based on the biopsychosocial model.

METHODS

Data from 4,076 women aged ≥45 years who participated in the Korea National Health and Nutrition Examination Survey from 2015 to 2020 were analyzed. Complex sampling analysis was performed using IBM SPSS ver. 26.0.

RESULTS

The combination of general and abdominal obesity was positively associated with age ≥65 years, postmenopausal status, and without breastfeeding experience among biomedical factors; depressive symptoms and prolonged (≥8 hours a day) sedentary behavior among psychosocial factors; and an educational level lower than middle or high school graduation and the first and second income quantiles among biosocial factors.

CONCLUSION

Healthcare providers in communities and public societies should screen for risk factors for the combination of general and abdominal obesity while considering non-modifiable biomedical (e.g., age) and biosocial factors (e.g., educational level). In addition, intervention strategies should be developed by considering modifiable psychosocial factors such as sedentary behavior.

Associations between socioeconomic status and risk of obesity and overweight among Chinese children and adolescents

BACKGROUND

In China, the threat of obesity and overweight in children and adolescents is developing quickly. It may be possible to lower the risk of obesity and overweight in children and adolescents by understanding the factors that drive these conditions. Therefore, this study aimed to investigate the association between SES and risk of obesity and overweight among children and adolesecnts in China's provinces of Jiangsu, Anhui, Zhejiang, and Shanghai.

METHODS

Chinese children and adolescents (n = 2,746; 46.3% boys) were recruited using multistage sampling. SES was measured using self-reported questionnaires, the specific indicators were parental education, perceived family wealth, and Family Affluence Scale II. Height and weight were measured and used to calculate body mass index (BMI, categorized into obesity or overweight). The definition of obesity or overweight was based on the Chinese standard "Screening for obesity and overweight among school-age children and adolescents". Descriptive statistics, independent sample t-tests, and a Chi-square test were used to report the sample characteristics and analyse BMI differences across different sociodemographic groups. A binary logistic regression was then applied to analyse the association of SES indicators with BMI in children and adolescents.

RESULTS

Overall, 22.5% of children and adolescents were obese or overweight. Participants with medium and high maternal education levels were 1.48 [95% CI 1.15-1.91] and 1.47 [95% CI 1.03-2.11] times more likely to be obese/overweight. Girls with medium maternal education levels were 1.70[95% CI 1.21-2.40] times more likely to be obese/overweight. For boys, no association was observed. Junior middle school students with medium maternal education levels were 1.51[95% CI 1.10-2.07] times more likely to be obese/overweight. Participants with medium or high FAS, perceived family wealth, or paternal education levels were not associated with obesity/overweight.

CONCLUSIONS

The findings of this study indicated a positive association between SES and risk of overweight/obesity in girls, suggesting that maternal education level may have a substantial impact on future prevention efforts for these conditions in girls. To increase the effectiveness of interventions, longitudinal studies are necessary to better understand the causal association between SES and obesity/overweight.

Trends for the Association between Body Mass Index and Risk of Cardiovascular Disease among the Japanese Population: The Circulatory Risk in Communities Study (CIRCS)

AIM

This study aimed to investigate whether the impact of body mass index (BMI) on the risk of cardiovascular disease (CVD) has changed among the 1960s, 1970s, 1980s, 1990s, and early 2000s in Japan.

METHODS

The study population consisted of residents in Japan aged 40-69 years who had no history of CVD. The baseline surveys have been conducted every year since 1963. We defined the first, second, third, fourth, and fifth cohorts as 1963-1969 (n=4,248), 1970-1979 (n=6,742), 1980-1989 (n=12,789), 1990-1999 (n=12,537), and 2000-2005 (n=9,140) respectively. The participants were followed up for a median of 15 years for each cohort to determine the incidence of CVD. We classified them into four categories (BMI ＜21.0, 21.0-＜23.0, 23.0-＜25.0, and ≥ 25.0 kg/m ²).

RESULTS

From 1963-1969 to 2000-2005, the prevalence of BMI ≥ 25.0 increased over time. Compared with BMI 23.0-＜25.0, the age-, sex- and community-adjusted hazard ratios (95% confidence interval [CIs]) of CVD for BMI ≥ 25.0 were 1.10 (0.77-1.57), 0.89 (0.68-1.18), 1.03 (0.85-1.26), 1.28 (1.04-1.58), and 1.36 (1.04-1.78)in the first, second, third, fourth, and fifth cohorts, respectively. The corresponding population attributable fractions were 2.0% (nonsignificant), -2.6% (nonsignificant), 0.9% (nonsignificant), 7.6%, and 10.9%. Further adjustment for systolic blood pressure and antihypertensive medication use in the fourth and fifth cohorts attenuated the associations, which may reflect that blood pressure may mediate the BMI-CVD association.

CONCLUSION

The proportion of CVD attributable to overweight/obesity has increased during the periods between 1963-1969 and 2000-2005. The significant associations between overweight/obesity and risk of CVD after the 1990s were mediated by blood pressure levels.

Association of Metabolic Health and Central Obesity With the Risk of Thyroid Cancer: Data from the Korean Genome and Epidemiology Study

BACKGROUND

It is unknown whether the risk of thyroid cancer differs among metabolically healthy/unhealthy, normal-weight, or obese women. We aimed to assess the association of metabolic health and obesity with thyroid cancer risk.

METHODS

The Korean Genome and Epidemiology Study is a population-based prospective cohort study. Data were obtained from 173,343 participants (age {greater than or equal to}40 years) enrolled from 2004 to 2013. Obese participants were those with body mass index (BMI) {greater than or equal to}25 kg/m2. Participants with abnormalities in three of these indices were considered metabolically unhealthy: triglycerides, blood pressure, high-density lipoprotein cholesterol (HDL-cholesterol), waist circumference (WC), and fasting glucose levels. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for thyroid cancer risk associated with metabolic health and obesity.

RESULTS

Compared to non-obese women without metabolic abnormalities, metabolically unhealthy women, either normal-weight or obese, had an increased risk of thyroid cancer (HR [95% CI]=1.57[1.02-2.40] and 1.71[1.21-2.41], respectively). Significant association was not observed in men. Thyroid cancer risk was higher among non-obese women with high WC ({greater than or equal to}85 cm; HR [95% CI]=1.62[1.03-2.56]) than in non-obese women with low WC, and in obese women with low HDL-cholesterol (<50 mg/dL; HR[95% CI]=1.75[1.26-2.42]) compared to non-obese women with high HDL-cholesterol.

CONCLUSIONS

Metabolically unhealthy women or women with central adiposity may be at an increased thyroid cancer risk despite normal BMI.

IMPACT

This study suggests that women with central obesity and metabolically abnormality despite normal BMI may constitute a target group for thyroid cancer prevention and control programs.

Socioeconomic Status, Institutional Power, and Body Mass Index among Chinese Adults

Despite the vast literature on the socioeconomic status (SES) gradient of obesity among adult people, no study has investigated the relationship between institutional power and body mass index. Using national survey data from the “China Labor-force Dynamics Survey 2016” (CLDS 2016), multistage cluster-stratified probability proportional to size (PPS) sampling was employed to select cases from 29 provinces, cities, and autonomous regions in China. This study adopts an institutional approach to explore the influences of SES and institutional power on the state of being overweight or severely overweight (obese) among Chinese adults. It is shown that SES has a non-linear influence on being overweight or obese, higher education has a negative effect on being overweight or obese, income has an inverted U-shaped effect on being overweight or obese, and having a managerial or administrative job has a positive effect on being overweight but less so on obesity. These findings reveal that disparities in health outcome and risks are due to inequality in SES. The work unit is a stronger predictor of adults being overweight or obese than occupation. Working in the public sector has a positive effect on being overweight relative to working in the private sector, and only state institutions and government departments have a positive association with obesity. Our results indicate that institutional structure still has effects on individuals’ life chances in the era of China’s market transition.