C-reactive protein mediates the association between leisure-time physical activity and lung function in middle-aged and older adults

Are C-reactive protein concentrations affected by smoking status and physical activity levels? A longitudinal study

BACKGROUND AND OBJECTIVE

To compare high-sensitivity C-reactive protein (hsCRP) levels according to smoking status and physical activity (PA) changes in adults.

METHODS

The sample consisted of 6028 participants (4833 men) who underwent a voluntary routine health evaluation at the Preventive Medicine Center at the Hospital Israelita Albert Einstein, Sao Paulo, Brazil, from January 2007 to December 2013. Data were collected at baseline and follow-up (2.7±1.6 years). Plasma hsCRP (in mg/L) was analyzed in both moments. Smoking status was obtained through a self-reported questionnaire, being participants classified as non-smokers, once smokers (report smoking at baseline or follow-up), and persistently smokers (reported smoking at both baseline and follow-up). PA was assessed by questionnaire in both moments, being participants classified as persistently inactive, became inactive, became active, and persistently active. The Rank Analysis of Covariance was used to compare hsCRP follow-up values according to smoking and physical activity status.

RESULTS

Persistently smokers showed significantly higher median values of hsCRP at follow-up (1.3 mg/L, IQR:0.6-2.8) than once smokers (1.1 mg/L, IQR: 0.6-2.4) and non-smokers (1.0 mg/L, IQR: 0.5-2.2), even considering covariates (p<0.001). Persistently actives had lower levels of hsCRP at follow-up when compared to persistently inactive in the three smoking status groups (non-smokers p<0.001, once smokers p = 0.001, and persistently smokers p = 0.037).

CONCLUSION

Persistently active participants had lower hsCRP values at follow-up than those persistently inactive in all the smoking status groups. Regular practice of PA is an important strategy for facing low-grade inflammation, even among smokers.

The chain mediating role of C-reactive protein and triglyceride-glucose index between lung function and cognitive function in a systemic low-grade inflammation state

OBJECTIVES

This study examined whether serum C-reactive protein (CRP) level and triglyceride-glucose index (TyG) explained the association between lung function and subsequent cognitive function in middle-aged and older adults with a systemic low-grade inflammation state.

DESIGN

A prospective cohort study.

SETTING AND PARTICIPANTS

The sample consisted of 1, 742 participants recruited from the English Longitudinal Study of Ageing (ELSA).

METHODS

Lung function and covariates were measured at baseline (wave 4, 2008/09). Serum CRP level and TyG were examined at a four-year follow-up (wave 6, 2012/13). Cognitive function was assessed at eight years post baseline (wave 8, 2016/17) in the main interview. The mediation was initially assessed using multivariate linear regression models. Indirect effects were assessed using the structural equation modeling and the bootstrap method.

RESULTS

We observed that serum CRP level and TyG significantly mediated the relationships between lung function (forced expiratory volume in 1s (FEV1) and forced vital capacity (FVC)) and cognitive function (immediate recall and delay recall). Moreover, serum CRP level mediated the association between lung function (FEV1 and FVC) and TyG. Our finding also suggested that FEV1 (1.19% mediated) and FVC (1.72% mediated) might influence cognitive function partly through the chain mediating role of both serum CRP level and TyG.

CONCLUSIONS AND IMPLICATIONS

The present study revealed that serum CRP level and TyG play a chain mediating role in the relationship between lung function at baseline and subsequent cognitive impairment in a nationally representative cohort of middle-aged and older adults with a systemic low-grade inflammation state.

Obesity-Related Indices Are Associated with Longitudinal Changes in Lung Function: A Large Taiwanese Population Follow-Up Study

The global pandemic of obesity and the increasing incidence of chronic respiratory diseases are growing health concerns. The association between obesity and pulmonary function is uncertain. Therefore, this study aimed to explore associations between changes in lung function and obesity-related indices in a large longitudinal study. A total of 9059 participants with no personal histories of asthma, smoking, bronchitis, or emphysema were enrolled from the Taiwan Biobank and followed for 4 years. Lung function was assessed using spirometry measurements including forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC). Changes in FEV1/FVC (∆FEV1/FVC) between baseline and follow-up were calculated. The following obesity-related indices were studied: lipid accumulation product (LAP), body roundness index (BRI), conicity index (CI), body adiposity index (BAI), abdominal volume index (AVI), body mass index (BMI), waist–hip ratio (WHR), and waist-to-height ratio (WHtR). In multivariable analysis, the subjects with high BMI (p < 0.001), WHR (p < 0.001), WHtR (p < 0.001), LAP (p = 0.002), BRI (p < 0.001), CI (p = 0.005), BAI (p < 0.001), and AVI (p < 0.001) were significantly associated with a high baseline FEV1/FVC. After 4 years of follow-up, the subjects with high BMI (p < 0.001), WHR (p < 0.001), WHtR (p < 0.001), LAP (p = 0.001), BRI (p < 0.001), CI (p = 0.002), BAI (p < 0.001), and AVI (p < 0.001) were significantly associated with a low △FEV1/FVC. High obesity-related index values were associated with better baseline lung function and a rapid decrease in lung function at follow-up.

Mediating effect of behavioural intention on podcast acceptance

This research contributes to knowledge in mediating effect of lecturers' behavioural intention towards the acceptance of podcasts technology in universities. A cross-sectional quantitative research design was involved in this study. Also, a total of eight hundred and twenty-nine (829) lecturers participated in this research from three different south-west Nigeria Federal universities. The research instrument was titled lecturer's acceptance questionnaire (LAQ) with a calculated Cronbach's alpha of .919, which confirmed the instrument validity. The gathered data was analysed by using both descriptive and inferential statistics. The formulated hypothesis was tested at .05 level of significance. The result from descriptive analysis of data suggested that behavioural intention was at a low level among lecturers and the results of hypothesis testing revealed the effect of behavioural intention as partial mediator of podcast acceptance. Based on these findings relevant conclusions and recommendations were suggested in this research.

Physical activity and lung function-Cause or consequence?

Concerns exist that the positive association of physical activity with better lung function, which has been suggested in previous longitudinal studies in smokers, is due to reverse causation. To investigate this, we applied structural equation modeling (SEM), an exploratory approach, and marginal structural modeling (MSM), an approach from the causal inference framework that corrects for reverse causation and time-dependent confounding and estimates causal effects, on data from participants in the European Community Respiratory Health Survey (ECRHS, a multicentre European cohort study initiated in 1991–1993 with ECRHS I, and with two follow-ups: ECRHS II in 1999–2003, and ECRHS III in 2010–2014). 753 subjects who reported current smoking at ECRHS II, with repeated data on lung function at ECRHS I, II and III, physical activity at ECRHS II and III, and potential confounders at ECRHS I and II, were included in the analyses. SEM showed positive associations between physical activity and lung function in both directions. MSM suggested a protective causal effect of physical activity on lung function (overall difference in mean β (95% CI), comparing active versus non-active individuals: 58 mL (21–95) for forced expiratory volume in one second and 83 mL (36–130) for forced vital capacity). Our results suggest bi-directional causation and support a true protective effect of physical activity on lung function in smokers, after accounting for reverse causation and time-dependent confounding.