Cigarette smoking and PM2.5 risk of metabolic syndrome

       Cigarette smoking and PM2.5 might jointly 

       exacerbate the risk of metabolic syndrome

Metabolic syndrome (MS) is a condition 

characterized by the coexistence of at least three metabolic risk markers, including impaired fasting blood glucose (sugar), dyslipidemia (low high-density cholesterol 

and high triglyceride), abdominal obesity (high waist circumference), and elevated blood pressure (1–4). MS is a public health challenge with a huge global burden: it enhances morbidity and mortality related to

 chronic diseases such as cancer, stroke, diabetes, asthma, and atherosclerotic and nonatherosclerotic cardiovascular disease (5–7). Metabolic risk factors such as blood pressure, fasting plasma glucose, and high total cholesterol were among the ten largest contributors to global disability-adjusted life years (DALYs) in 2015 (8). MS has multiple promoting factors including, age (9), unhealthy diet (10, 11), obesity (11), alcohol consumption (12, 13),

 physical inactivity (11, 13), cigarette smoking (13–23), and PM2.5 (24–27).

Cigarette smoking is a major preventable promoter

 of global cardiovascular mortality and 

morbidity (16, 28, 29). 

In 2015, it was among the five top risk factors attributable

 to global DALYs in 109 countries (8).

 The influence of cigarette smoking on MS and its

 components is contentious (14, 30). 

For instance, cigarette smoking was a significant

 cause of MS among Chinese (14), Koreans (31–33), and Japanese (18, 23). Nonetheless, it was not significantly associated with MS among Japanese (34) and Chinese (35). Furthermore, heavy cigarette smoking among Turkish women was suggested as being protective against future MS (36).

Air pollution, especially PM2.5 (fine PM) is 

an urgent global public health concern, with continuously increasing implications (4, 9, 37–46). 

It significantly enhances neurological and cardiovascular morbidity and mortality (47, 48). Several studies reported contrasting findings regarding the relationship between MS and PM2.5 (14–23, 31–33, 49–51). A recent systematic review and meta-analysis found that PM2.5 could contribute to as much as 12.28% of MS (52). 

In several original studies, PM2.5 exposure significantly elevated the risk of MS among Chinese (25–27, 53, 54),

 Saudi (55), and Korean adults (56). 

On the contrary, PM2.5 did not significantly affect the risk of MS among Germans (57) and Chinese (50).

The positive association between PM2.5

 and MS was more prominent in cigarette smokers, alcohol drinkers, and obese people (25, 26, 53).

 This suggests that smoking and other unhealthy

 habits could exacerbate the adverse effects of air pollution (25, 26, 53). Smoking could also confound the effect of air pollution on cardiovascular health (58). 

Hence, pinpointing the combined effect of 

cigarette smoking and PM2.5 could narrow

 the data gap for the burden of disease attributable to both exposures (59).

 Moreover, determining the interaction between 

PM2.5 and smoking could provide insightful knowledge regarding the susceptibility to PM2.5-related 

adverse health conditions in smokers and 

nonsmokers (59). 

High exposure to PM2.5 among Chinese was recently associated with a higher risk of hypertension caused by smoking (60).

 However, robust studies have not been conducted to determine the combined effect of PM2.5 and cigarette smoking on MS.

 In the current study, we determined the independent association of ambient PM2.5 and smoking with MS in Taiwanese adults. Moreover, we determined

the independent association of ambient PM2.5 

and smoking with MS in Taiwanese adults. Moreover, we determined the interaction between PM2.5 and smoking regarding MS

Ref

DrFront Public Health. 2024 Jan 15;11:1234799. doi: 10.3389/fpubh.2023.1234799

Cigarette smoking and PM2.5 might jointly exacerbate the risk of metabolic syndrome

Hao-Hung Tsai 1,2,3,4,5, Disline Manli Tantoh 3,6, 

Wen Yu Lu 6, Chih-Yi Chen 1,7,*, Yung-Po Liaw 3,6,*