Exposure to fine particulate matter (PM2.5) is linked to increased systemic inflammation, particularly in individuals with metabolic syndrome (MS). This study assessed the impact of nutrition and PM2.5 exposure on inflammatory markers in individuals with MS. A total of 50 participants (25 with MS, 25 healthy controls) were monitored during a high-PM2.5 exposure period (HEP) and a low-PM2.5 exposure period (LEP). Dietary intake, health assessments, and inflammatory markers—TNF-α, IL-6, and CRP—were evaluated. The MS group had significantly higher BMI, fasting blood glucose, and triglyceride levels and lower HDL-C than the healthy group (p < 0.01), but these parameters did not change significantly between the HEP and LEP. Notably, dietary fiber intake increased in the MS group during the LEP (p < 0.05). CRP levels were higher in the MS group and significantly decreased in both groups during the LEP (p < 0.05). IL-6 was higher in the MS group during the HEP but did not significantly change across periods. TNF-α showed no differences. Dietary fiber intake was inversely correlated with IL-6 and CRP in the healthy group and strongly correlated with CRP in the MS group (r = −0.403, p < 0.01). Antioxidant vitamins were inversely correlated with inflammation only in healthy participants. These findings suggest that an increased dietary fiber intake may help reduce PM2.5-induced inflammation, particularly in individuals with MS.

Northern Thailand experiences annual haze events with fine particulate matter (PM2.5) exceeding standards, posing risks to schoolchildren. This cross-sectional study (Chiang Mai, 2024) evaluated respiratory impacts among primary school children aged 8–12 years. Daily mean PM2.5 concentrations were obtained from a single fixed-site monitoring station (36T) located within 2 km of the spirometry site. Among 93 children with acceptable spirometry, 52% exhibited restrictive, 18% obstructive, and 30% had normal function. After adjustment for BMI, males had significantly lower odds of any pulmonary abnormality than females (AOR = 0.084; 95% CI 0.017–0.417; p = 0.002). The mean FEV₁/FVC ratio was normal (86.30 ± 13.07%), whereas mean FVC, FEV₁, and PEF were significantly below predicted values, indicating a predominantly restrictive pattern. This predominance likely reflects cumulative exposure to biomass-burning related PM2.5 during the haze season, infiltration of outdoor PM2.5 into indoor environments alongside indoor sources, and the vulnerability of developing lungs in children’s factors that reduce lung volumes while largely preserving the FEV₁/FVC ratio. The exposure assessment provides pragmatic, proximity-based estimates but is limited by reliance on one station and one season, which may not capture spatial or temporal variability. These findings highlight sex-based susceptibility and support stronger air quality protections for children.

Exposure to fine particulate matter (PM_2.5) is linked to metabolic dysfunction, yet evidence on its impact on hormonal regulation remains limited. This study examined seasonal changes in insulin, adiponectin, leptin, and HOMA-IR levels among healthy individuals and those with metabolic syndrome (MS) in Chiang Mai, Thailand. Fifty participants (25 healthy, 25 with MS) were assessed during high (February–April)- and low (May–July)-PM_2.5 seasons. Insulin levels increased in healthy individuals (mean: 9.3 to 14.9 µIU/mL; p = 0.051) and decreased in participants with MS (22.0 to 13.7 µIU/mL; p = 0.214), with a significant interaction effect (p = 0.020). Leptin increased significantly in both groups, but more markedly in the MS group (p < 0.001), also with a significant interaction (p < 0.001). HOMA-IR rose significantly in healthy individuals (p = 0.036) but not in participants with MS. Adiponectin remained stable across groups and seasons. At baseline, the MS group had significantly higher rates of diabetes (p = 0.050), hypertension (p = 0.001), and hyperlipidemia (p = 0.049). These findings suggest that PM_2.5 may influence metabolic and hormonal profiles, particularly in individuals with existing metabolic disorders.