Expanded normal weight obesity and blood pressure in Chinese adults: a community-based cross-sectional study

Association between normal weight obesity and comorbidities and events of cardiovascular diseases among adults in South China

BACKGROUND

The increased risks for cardiovascular comorbidities and cardiovascular diseases (CVD) in populations with normal weight obesity (NWO) have not been well-identified. We aimed to study their associations in an adult population in South China.

METHODS

Based on the CVD prevalence of 4% in Shenzhen and a calculated sample size of 6,000, a cross-sectional study with a multi-stage stratified cluster sampling method was conducted in Shenzhen City. The cardiovascular comorbidities being studied were abdominal obesity (AO), diabetes, hypertension, dyslipidemia, metabolic syndrome, and chronic kidney disease, while the CVD events were occurrences of myocardial infarction and strokes. Questionnaire surveys, physical examinations, and laboratory tests were performed. NWO was defined as a condition with the highest tertile of body fat percentage (BF%) among the normal body mass index (BMI) range (18.5-23.9 kg/m2). Continuous data were reported as mean [standard deviation (SD)] and categorical data as percentages (%). CVD comorbidities and CVD events and their detection rates in different groups were compared using ANONA analysis and Chi-squared test. Spearman's correlation coefficients between BF% and cardiometabolic abnormalities were calculated by partial correlation analysis. Multivariate logistic regression models were used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) for BF%, CVD comorbidities, and CVD events, adjusted for multiple confounders.

RESULTS

Among the total 6,240 subjects who completed the study and had BMI and BF% data available, 3,086 had normal BMI. The prevalence of NWO was 16.36%, with 13.15% for men and 19.54% for women. With confounders adjusted, the risks of AO (OR = 6.05, 95%CI = 3.40-10.75), essential hypertension (OR = 1.56, 95%CI = 1.09-2.22), dyslipidemia (OR = 1.85, 95%CI = 1.49-2.29), and metabolic syndrome (OR = 4.61, 95%CI = 2.32-9.18) were significantly increased in the populations with NWO compared with the population without NWO (P < 0.05). BF% was not significantly associated with the risk of CVD events in the total (OR = 1.56, 95%CI = 0.83-2.93), male (OR = 1.00, 95%CI = 0.44-2.30), and female populations (OR = 2.53, 95%CI = 0.91-7.06).

CONCLUSION

NWO was found to be positively associated with CVD comorbidities but not with CVD events. The current study provides a ground to conduct further studies on whether body fat affects the risk of occurrence of CVD events and the underlying mechanisms in the future.

Effects of time-restricted feeding and walking exercise on the physical health of female college students with hidden obesity: a randomized trial

Purpose

Time-restricted feeding (TRF) is an emerging dietary pattern with many potential effects. This study focused on the effects of TRF and walking on the physical health of female college students with hidden obesity.

Methods

A total of 77 female college students with hidden obesity, aged 18-22 years, were randomly assigned to a control group (CON, N = 19), time-restricted feeding group (TRF, N = 19), exercise group (EXE, N = 20), and TRF combined with exercise group (TRF + EXE, N = 19). The interventions lasted for 8 weeks. Tests assessing body shape, body composition, bone mineral density, blood lipid levels, and blood pressure were performed before and after the intervention.

Results

(1) Intragroup comparison before and after the intervention revealed that the TRF, EXE, and TRF + EXE groups had significantly reduced body weight (p < 0.01), body mass index (BMI) (p < 0.05), and lean tissue mass (LTM) (p < 0.01) but increased total cholesterol (TC) levels (p < 0.05) after the intervention. Body fat percentage (BF%) increased considerably in the EXE and TRF + EXE groups (p < 0.01). (2) Post-intervention comparisons of body weight, BMI, LTM, adipose tissue mass (ATM), total bone mineral density (TBMD), blood lipid levels, and blood pressure between the intervention groups (TRF, EXE, and TRF + EXE) and the CON group showed no significant differences (p > 0.05). (3) A comparison of the changes between the groups before and after the intervention showed significant decreases in body weight in the TRF and TRF + EXE groups (p < 0.05) and in both BMI and LTM in the TRF, EXE, and TRF + EXE groups (p < 0.05) compared to those in the CON group. The BF% change in the EXE and TRF + EXE groups were significantly greater than that in the TRF group (p < 0.01).

Conclusion

TRF effectively decreased body weight and BMI in female college students with hidden obesity. However, increased blood lipid levels and decreased LTM levels were also observed. The effects of TRF combined with exercise were not superior to those of TRF or walking alone in terms of body weight, body mass index, body composition, TBMD, or blood lipid levels. Therefore, TRF cannot be considered the best option for fat reduction in female college students with hidden obesity.

Body mass index combined with (waist + hip)/height accurately screened for normal-weight obesity in Chinese young adults

OBJECTIVES

Only a few studies have explored the prevalence of normal-weight obesity in young adults or the development of a simple evaluation index for body fat percentage. Therefore, this study aimed to examine the prevalence of normal-weight obesity in young Chinese adults and use anthropometric measurements to develop an evaluation index.

METHODS

In total, 1322 college students participated in the study and were divided into the normal-weight lean, normal-weight obese, and overweight and obese groups based on their body mass index and body fat percentage. The differences in body composition, circumference, and circumference ratio among these three groups were examined.

RESULTS

When exploring the correlation between the circumference ratio and body fat percentage, the circumference ratio was suitable for early screening of abnormal body fat percentage, and the cutoff value was calculated. Body composition and circumference were significantly different among the three groups: (waist + hip)-to-height, hip-to-height, and waist-to-height ratios were strongly correlated with body fat percentage.

CONCLUSIONS

(Waist + hip)-to-height ratio can be used as a simple evaluation index for indicating abnormal body fat percentage when higher than 1.032 in male and 1.047 in female individuals. Downregulating the normal upper limit for body mass index to 24.4 and 23.8 kg/m² in male and female individuals, respectively, is recommended. Body mass index combined with (waist + hip)-to-height ratio allowed for more accurate screening of normal-weight obesity as an easy and cost-free evaluation measure for abnormal body fat percentage.

The association between muscle-to-fat ratio and cardiometabolic risks: The China National Health Survey

BACKGROUND

The relationship between muscle mass and fat mass might be an indicator to assess the cardiometabolic risk independently from overweight/obesity, but evidence from a representative general Chinese population is lacking.

OBJECTIVE

To understand the age- and sex-specific associations between muscle-to-fat ratio (MFR) and cardiometabolic risks in Chinese population.

METHODS

31,178 (12,526 men and 18,652 women) subjects from the China National Health Survey were included. Muscle mass and fat mass were assessed by a bioelectrical impedance device. MFR was calculated as muscle mass divided by fat mass. Systolic blood pressure (SBP) and diastolic blood pressure (DBP), serum lipids, fasting plasma glucose and serum uric acid were measured. General linear regressions, quantile regressions and restricted cubic-spline (RCS) regressions were applied to assess the effect of MFR on cardiometabolic profiles.

RESULTS

Per unit increase of MFR was associated with a 0.631 (0.759-0.502) mmHg SBP decrease in men, 2.648 (3.073-2.223) in women; 0.480 (0.568-0.392) mmHg DBP decrease in men, 2.049 (2.325-1.774) in women; a 0.054 (0.062-0.046) mmol/L total cholesterol decrease in men, 0.147 (0.172-0.122) in women; 0.084 (0.098-0.070) mmol/L triglycerides decrease in men, 0.225 (0.256-0.194) in women; a 0.045 (0.054-0.037) mmol/L low-density lipoprotein decrease in men, 0.183 (0.209-0.157) in women; a 2.870 (2.235-3.506) μmol/L serum uric acid decrease in men, 13.352 (14.967-11.737) in women; and a 0.027 (0.020-0.033) mmol/L high-density lipoprotein increase in men, 0.112 (0.098-0.126) mmol/L in women. The effect in overweight/obese people was much significant than in under/normal weight counterparts. The RCS curves revealed both linear and non-linear relationships between increased MFR and lower cardiometabolic risk.

CONCLUSIONS

Muscle-to-fat ratio is independently associated with multiple cardiometabolic parameters among Chinese adults. Higher MFR is related with better cardiometabolic health, and the effect is much significant in overweight/obese people and women.

Normal Weight Obesity and Cardiometabolic Risk Factors: A Systematic Review and Meta-Analysis

BACKGROUND

Obesity is one of the most significant causes of morbidity and mortality worldwide. Current studies suggest a new type of obesity, normal weight obesity (NWO), which is defined as having a normal body mass index (BMI), but a high-fat percentage increases the risk of cardiometabolic risk factors (CMRFs). This systematic review and meta-analysis aimed to pool the association between NWO with CMRFs.

METHODS

A systematic search of the literature in all available electronic databases, including Scopus, Web of Science, EMBASE, and PubMed, was performed until October 2021. All English studies that assessed the association of NWOs [compared to normal weight non-obese (NWNO)] and the CMRFs were included. Two investigators extracted data and performed a quality assessment. The heterogeneity between studies was assessed with I-squared and Cochran's Q tests. Odds ratio (OR) was used as an effect size to pool the association of NWO with CMRFs.

RESULTS

Twenty-five articles that met the inclusion criteria entered the study. The total number of participants was 177,792, with an age range of 13 to 75 years. Most studies were conducted on the general population (adults) and were from China. The result of fixed-effect model meta-analysis indicated an increased odds of hyperglycemia (OR:1.50, 95%:1.23, 1.76), high TG (OR:1.90, 95% CH:1.44, 2.35), low HDL (OR: 1.28, 95% CI:1.06, 1.49) and diabetes (OR:1.39, 95% CI:1.30, 1.49). Moreover, the random effect meta-analysis showed that NWO increased the odds of dyslipidemia (OR:1.83, 95% CI:1.61, 20.4), HTN (OR:1.40, 95% CI:1.28, 1.51) and metabolic syndrome (OR:1.92, 95% CI:1.58, 2.26). Moreover, the mean of all CMRFs except plasma glucose in NWO subjects was statistically higher than NWNO subjects (p-value<0.05).

CONCLUSION

The present study showed that NWO increased the odds of CMRFs. These findings indicate the inadequacy of the BMI measurement and the need for body fat assessment for a better obesity risk assessment.

Normal weight obesity and unaddressed cardiometabolic health risk-a narrative review

Normal weight obesity (NWO) is defined as having a normal body mass index (BMI), but a high body fat mass. There is growing interest in individuals with NWO, which is an underdiagnosed and understudied group, because of their increased risk for cardiometabolic morbidity and mortality. In this review, we summarized the definition, prevalence, etiology, pathophysiology, and cardiovascular outcomes seen in NWO. We have also summarized the available literature on interventions for NWO. There is a wide variation in the body fat percent cutoffs used to diagnose excess body fat. Hence, the prevalence rates of NWO vary between different populations and studies. It is estimated that about 30 million Americans have NWO and the worldwide prevalence ranges from 4.5% to 22%. Genetics, diet, and physical activity are related to NWO. However, etiological factors are not clear. Changes in body composition, inflammation, oxidative stress are present in NWO in comparison to normal weight lean (NWL) who have a normal BMI and normal body fat amount. Furthermore, cardiometabolic changes are observed and some are subclinical. Thus, screening for NWO will enhance the primary prevention of cardiovascular disease. Due to the use of various body fat percent cutoffs and methods to measure body fat, it is challenging to compare between studies. Researchers working in this field should ideally work towards developing standard body fat percent cutoffs for diagnosing NWO. There are many gaps in the literature on NWO unlike for overt obesity and future studies should explore the etiology, molecular mechanisms, and adipose tissue changes of NWO as well as conduct well planned and executed randomized controlled trials testing dietary, physical, and behavioral interventions for NWO in both males and females of different racial and age groups.

Moderating effect of age on the relationships between pre-frailty and body measures

This study aims to investigate the relationship between body measures and the presence of two frailty-related phenotypes, and the moderating effect of age on this relationship. This is a secondary data analysis of the baseline data of an interventional study. The participants were residents of seven districts in Hong Kong, aged 55 or older, able to ambulate independently and to function well cognitively. Pre-frailty refers to the presence of two frailty-related phenotypes: low physical activity or poor handgrip strength or both. Included in the study were 199 individuals with a mean age of 73.43 (SD 7.54). Regression models showed that body weight (OR = 0.95, 95% CI 0.92-0.99, p < .05) was significantly associated with pre-frailty, as was body height (OR = 0.88, 95% CI 0.83-0.94, p < .001). Age is a significant moderator of the relationship between pre-frailty and body weight and body height. The effect of body weight (beta = -0.044, p < .05) and height (beta = -0.16, p < .001) on pre-frailty was significant and negative in the younger age groups. The findings indicate that raw body measures (i.e. body weight, body height) are more predictive of pre-frailty than BMI in older Chinese people. However, in the old-old group, these measures are not significant predictors of pre-frailty in Chinese community-dwelling adults. Practitioners should consider adopting body measures as predictors of pre-frailty in the younger-old population.