Trends in the prevalence of metabolically healthy and unhealthy obesity in the US adult population: analysis of eight NHANES cross-sectional survey cycles, 1999-2014

Weight loss methods and risk of depression: Evidence from the NHANES 2005-2018 cohort

BACKGROUND

Weight loss behaviors are increasingly common worldwide. While healthy weight loss methods, such as calorie control and exercise, can improve both physical and mental health, harmful practices-such as extreme dieting and the misuse of diet pills-may contribute to depressive symptoms. Understanding the psychological impact of different weight loss strategies is essential for promoting overall well-being.

METHODOLOGY

Data from 9334 non-pregnant participants aged 20-79 years from the 2005-2018 National Health and Nutrition Examination Survey (NHANES) were analyzed. The sample consisted of 60.72 % women and 39.28 % men, with a median age of 47 years and a median BMI of 28.84. Depressive symptoms were assessed using the PHQ-9 scale. Weight loss methods were categorized into healthy practices (e.g., calorie control, exercise) and harmful practices (e.g., extreme dieting, diet pills). Logistic regression models were applied, adjusting for demographic and health factors.

RESULTS

Protective methods, including switching to lower-calorie foods (OR = 0.80, 95 % CI = 0.68-0.94), exercising (OR = 0.61, 95 % CI = 0.53-0.72), and eating more fruits and vegetables (OR = 0.78, 95 % CI = 0.66-0.92), were associated with a reduction in depressive symptoms. In contrast, harmful methods such as skipping meals (OR = 1.71, 95 % CI = 1.45-2.02), using diet pills (OR = 1.90, 95 % CI = 1.34-2.69), and vomiting (OR = 2.61, 95 % CI = 1.62-4.21) increased the risk of depressive symptoms. The number of harmful methods was positively correlated with increased depressive symptom risk (OR = 2.72, 95 % CI = 2.09-3.54), while a higher number of protective methods was linked to a decreased risk (OR = 0.50, 95 % CI = 0.37-0.68).

CONCLUSION

The emotional impact of weight loss practices is significant. Healthy weight loss strategies, such as exercise and calorie control, reduce the risk of depressive symptoms, whereas harmful methods increase the risk. These findings underscore the importance of promoting safe and sustainable weight loss methods to protect both physical and mental health.

Exploring metabolically healthy obesity: prevalence, characteristics, and cardiovascular risk in the Iranian population based on the STEPS 2021

Background

Regarding the rapidly increasing prevalence of obesity throughout the globe, it remains a serious public health concern. A subgroup of obesity that does not meet metabolic syndrome criteria is called metabolically healthy obesity (MHO). However, whether the MHO phenotype increases cardiovascular disease (CVD) risk is controversial. This study aimed to evaluate the prevalence of MHO and its 10-year CVD risk in Iranian populations.

Methods

Based on the STEPS 2021 project in Iran, we collected data on 18119 Iranians 25 years and older from all 31 provinces after applying many statistical factors. Using the Framingham score, we evaluated the 10-year cardiovascular risk associated with the various MHO definition criteria for Iranian populations.

Results

The prevalence of MHO was 6.42% (5.93-6.91) at the national level according to the AHA-NHLBI definition, and 23.29% of obese women and 24.55% of obese men were classified as MHOs. Moreover, the MHO group was younger than the metabolically unhealthy obesity (MUO) group based on all definitions (p < 0.001). The odds ratio of MUO individuals being classified as high-risk individuals by the Framingham criteria for CVD was significantly higher than that of MHO individuals by all definitions, with a crude odds ratio of 3.55:1 based on AHA-NHLBI definition.

Conclusion

This study reveals a significant prevalence of MHO in the Iranian population, with approximately 25% of obese individuals classified as MHO. While MHO is associated with a lower risk of cardiovascular disease compared to MUO, MHO carries the potential for transitioning to an unhealthy state.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-023-01364-5.

Phthalate metabolites and sex steroid hormones in relation to obesity in US adults: NHANES 2013-2016

Background

Obesity and metabolic syndrome pose significant health challenges in the United States (US), with connections to disruptions in sex hormone regulation. The increasing prevalence of obesity and metabolic syndrome might be associated with exposure to phthalates (PAEs). Further exploration of the impact of PAEs on obesity is crucial, particularly from a sex hormone perspective.

Methods

A total of 7780 adult participants in the National Health and Nutrition Examination Survey (NHANES) from 2013 to 2016 were included in the study. Principal component analysis (PCA) coupled with multinomial logistic regression was employed to elucidate the association between urinary PAEs metabolite concentrations and the likelihood of obesity. Weighted quartiles sum (WQS) regression was utilized to consolidate the impact of mixed PAEs exposure on sex hormone levels (total testosterone (TT), estradiol and sex hormone-binding globulin (SHBG)). We also delved into machine learning models to accurately discern obesity status and identify the key variables contributing most to these models.

Results

Principal Component 1 (PC1), characterized by mono(2-ethyl-5-carboxypentyl) phthalate (MECPP), mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), and mono(2-ethyl-5-oxohexyl) phthalate (MEOHP) as major contributors, exhibited a negative association with obesity. Conversely, PC2, with monocarboxyononyl phthalate (MCNP), monocarboxyoctyl phthalate (MCOP), and mono(3-carboxypropyl) phthalate (MCPP) as major contributors, showed a positive association with obesity. Mixed exposure to PAEs was associated with decreased TT levels and increased estradiol and SHBG. During the exploration of the interrelations among obesity, sex hormones, and PAEs, models based on Random Forest (RF) and eXtreme Gradient Boosting (XGBoost) algorithms demonstrated the best classification efficacy. In both models, sex hormones exhibited the highest variable importance, and certain phthalate metabolites made significant contributions to the model's performance.

Conclusions

Individuals with obesity exhibit lower levels of TT and SHBG, accompanied by elevated estradiol levels. Exposure to PAEs disrupts sex hormone levels, contributing to an increased risk of obesity in US adults. In the exploration of the interrelationships among these three factors, the RF and XGBoost algorithm models demonstrated superior performance, with sex hormones displaying higher variable importance.

Changing epidemiology, global trends and implications for outcomes of NAFLD

Non-alcoholic fatty liver disease (NAFLD) has rapidly become the most common liver disease globally and is currently estimated to affect 38% of the global population. Only a minority of patients with NAFLD will progress to cirrhosis or hepatocellular carcinoma, but from this vast population the total number of patients who are at risk of such severe outcomes is increasing. Worryingly, individuals are increasingly being affected by NAFLD at an earlier age, meaning there is more time for them to develop severe complications. With considerable changes in dietary composition and urbanisation, alongside the growth in obesity and type 2 diabetes in the global population, in particular in developing countries, the global proportion of persons affected by NAFLD is projected to increase further. Yet, there are large geographical discrepancies in the prevalence rates of NAFLD and its inflammatory component non-alcoholic steatohepatitis (NASH). Such differences are partly related to differing socio-economic milieus, but also to genetic predisposition. In this narrative review, we discuss recent changes in the epidemiology of NAFLD and NASH from regional and global perspectives, as well as in special populations. We also discuss the potential consequences of these changes on hepatic and extrahepatic events.