Association between body mass index (BMI) and vital capacity of college students of Zhuang nationality in China: a cross-section study

The impact of obesity on lung function measurements and respiratory disease: A Mendelian randomization study

INTRODUCTION

Observational studies have shown that body mass index (BMI) and waist-to-hip ratio (WHR) are both inversely associated with lung function, as assessed by forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1). However, observational data are susceptible to confounding and reverse causation.

METHODS

We selected genetic instruments based on their relevant large-scale genome-wide association studies. Summary statistics of lung function and asthma came from the UK Biobank and SpiroMeta Consortium meta-analysis (n = 400,102). After examining pleiotropy and removing outliers, we applied inverse-variance weighting to estimate the causal association of BMI and BMI-adjusted WHR (WHRadjBMI) with FVC, FEV1, FEV1/FVC, and asthma. Sensitivity analyses were performed using weighted median, MR-Egger, and MRlap methods.

RESULTS

We found that BMI was inversely associated with FVC (effect estimate, -0.167; 95% confidence interval (CI), -0.203 to -0.130) and FEV1 (effect estimate, -0.111; 95%CI, -0.149 to -0.074). Higher BMI was associated with higher FEV1/FVC (effect estimate, 0.079; 95%CI, 0.049 to 0.110) but was not significantly associated with asthma. WHRadjBMI was inversely associated with FVC (effect estimate, -0.132; 95%CI, -0.180 to -0.084) but has no significant association with FEV1. Higher WHR was associated with higher FEV1/FVC (effect estimate, 0.181; 95%CI, 0.130 to 0.232) and with increased risk of asthma (effect estimate, 0.027; 95%CI, 0.001 to 0.053).

CONCLUSION

We found significant evidence that increased BMI is suggested to be causally related to decreased FVC and FEV1, and increased BMI-adjusted WHR could lead to lower FVC value and higher risk of asthma. Higher BMI and BMI-adjusted WHR were suggested to be causally associated with higher FEV1/FVC.

Comparative Study of the Effects of Tai Chi and Square Dance on Immune Function, Physical Health, and Life Satisfaction in Urban Empty-Nest Older Adults

Objective: To compare the effects of Tai Chi and Square dance on immune function, physical health, and life satisfaction in urban, empty-nest older adults.

Methods: This cross-sectional study included 249 older adults (60–69 years) who were categorized into Tai Chi (n = 81), Square dance (n = 90), and control groups (n = 78). We evaluated immunoglobulin G (IgG) and interleukin-2 (IL-2) levels by enzyme-linked immunosorbent assay (ELISA), natural killer (NK) cell cytotoxicity by MTT assay, physical health indices by physical fitness levels, and life satisfaction by Life Satisfaction Index A (LSIA) scores.

Results: Immune function, physical health, and life satisfaction in older adults in the Tai Chi and Square dance groups were significantly better than those in the control group (P < 0.05). Regarding immune function and physical health, the Tai Chi group exhibited significantly higher levels of IgG (15.41 ± 0.26 g/L vs. 11.99 ± 0.35 g/L, P < 0.05), IL-2 (4.60 ± 0.20 ng/mL vs. 4.45 ± 0.21 ng/mL, P < 0.05), and NK cell cytotoxicity (0.28 ± 0.02 vs. 0.22 ± 0.02, P < 0.05) than the square dance group, significantly lower waist-to-hip ratio (0.87 ± 0.02 vs. 0.89 ± 0.02, P < 0.05), resting pulse (78.4 ± 4.6 beats/min vs. 81.0 ± 3.1 beats/min, P < 0.05), systolic blood pressure (132.0 ± 5.2 mmHg vs. 136.2 ± 3.2 mmHg, P < 0.05), diastolic blood pressure (80.0 ± 2.6 mmHg vs. 83.0 ± 2.7 mmHg, P < 0.05), and significantly higher vital capacity (2978.0 ± 263.0 mL vs. 2628.3 ± 262.8 mL, P < 0.05) and duration of one-leg standing with eyes closed (16.2 ± 1.9 s vs. 12.0 ± 1.7 s). However, there was no significant difference in LSIA scores between the Tai Chi and Square dance groups (12.05 ± 1.96 vs. 13.07 ± 1.51, P > 0.05). Further, there was a significant correlation between LSIA scores and immune function (r = 0.50, P = 0.00) and physical health (r = 0.64, P = 0.00).

Conclusion: (1) Both Tai Chi and square dance practitioners had better health outcomes, compared with sedentary individuals; (2) Tai Chi practitioners had better physical health and immune function than Square dance practitioners. (3) Tai Chi and Square dance exercises had similar effects on life satisfaction among urban empty-nest older adults.

Suggestions: For urban empty-nest older adults who want to have better physical health and immune function, long-term Tai Chi exercise may be a better choice; however, those who are concerned about life satisfaction can choose either Tai Chi or Square dance exercise.

Effect of muscle distribution on lung function in young adults

BACKGROUND

At present, available research on the relationship between muscle distribution and respiratory function in healthy people is limited.

OBJECTIVE

To study the relationship between muscle distribution and lung function in healthy young adults.

METHODS

A total of 612 male and 1561 Female Chinese college students were recruited. visceral fat tissue (VAT), subcutaneous fat tissue (SAT), total body muscle mass (TMM), trunk muscle mass (TKMM), upper limb muscle mass (ULMM) and lower limb muscle mass (LLMM) was measured by body composition. Vital capacity (VC) was measured by spirometry instrument. Obesity classification was defined by muscle mass ratio (MMR), body mass index (BMI), body fat percentage (BFP), waist-to-hip ratio (WHR).

RESULTS

Among these positive correlation parameters, male VC had a high positive correlation with TMM and LLMM, while female VC had a high positive correlation with TMM and TKMM. After the population was divided into MMR, BMI, BFP, and WHR, further analysis showed that VC was positively correlated with TMM for males with MMR-low muscle (r = 0.483; p < 0.05), BMI-underweight (r = 0.265; p < 0.05), BMI-overweight + obesity (r = 0.272; p < 0.05), BFP-low fat (r = 0.306; p < 0.05), and WHR-normal subgroups (r = 0.316; p < 0.05), while LLMM was positively correlated with VC in the MMR-normal muscle (r = 0.285; p < 0.05), BMI-normal (r = 0.305; p < 0.05), BFP-normal fat (r = 0.304; p < 0.05), and WHR obesity subgroups (r = 0.266; p < 0.05). VC was positively correlated with TMM for females with MMR-low muscle (r = 0.169; p < 0.05), MMR-normal muscle (r = 0.241; p < 0.05), BMI-underweight (r = 0.241; p < 0.05), BMI-normal (r = 0.288; p < 0.05), WHR normal (r = 0.275; p < 0.05), and BFP-low fat subgroups (r = 0.255; p < 0.05), while TKMM was positively correlated with VC in the BMI-overweight + obesity (r = 0.342; p < 0.05), WHR-obesity (r = 0.227; p < 0.05), and BFP-normal subgroups (r = 0.256; p < 0.05).

CONCLUSIONS

Muscle distribution in young adults is highly correlated with VC, and this relationship is affected by gender and body types. In general, for thin, VC is more positively correlated with TMM, and for normal weight or obese, VC is more positively correlated with LLMM for males but with TKMM for females, respectively, in comparison with other tested indices. Further studies will be required to evaluate the relationship between muscle distribution and vital capacity in young adults.

Associations between Particulate Matter and Otitis Media in Children: A Meta-Analysis

Particulate matter (PM), a primary component of air pollution, is a suspected risk factor for the development of otitis media (OM). However, the results of studies on the potential correlation between an increase in the concentration of PM and risk of developing OM are inconsistent. To better characterize this potential association, a meta-analysis of studies indexed in three global databases (PubMed, EMBASE, and The Cochrane Library) was conducted. These databases were systematically screened for observational studies of PM concentration and the development of OM from the time of their inception to 31 March 2020. Following these searches, 12 articles were analyzed using pooled odds ratios generated from random-effects models to test for an association between an increased concentration of PM and the risk of developing OM. The data were analyzed separately according to the size of particulate matter as PM_2.5 and PM₁₀. The pooled odds ratios for each 10 μg/m³ increase in PM_2.5 and PM₁₀ concentration were 1.032 (95% confidence interval (CI), 1.005–1.060) and 1.010 (95% CI, 1.008–1.012), respectively. Specifically, the pooled odds ratios were significant within the short-term studies (PM measured within 1 week of the development of OM), as 1.024 (95% CI, 1.008–1.040) for PM_2.5 concentration and 1.010 (95% CI, 1.008–1.012) for PM₁₀ concentration. They were significant for children under 2 years of age with pooled odds ratios of 1.426 (95% CI, 1.278–1.519) for an increase in the concentration of PM_2.5. The incidence of OM was not correlated with the concentration of PM, but was correlated with an increase in the concentration of PM. In conclusion, an increase in the concentration of PM_2.5 is more closely associated with the development of OM compared with an increase in the concentration of PM₁₀; this influence is more substantial in shorter-term studies and for younger children.