CDH13 gene-by-PM10 interaction effect on lung function decline in Korean men

[Effect of modification of antihypertensive medications on the association of nitrogen dioxide long-term exposure and chronic kidney disease]

OBJECTIVE

To investigate the potential effect of modification of antihypertensive medications on the association of nitrogen dioxide (NO₂) long-term exposure and chronic kidney disease (CKD).

METHODS

Data of the national representative sample of adult population from the China National Survey of Chronic Kidney Disease (2007-2010) were included in the analyses, and exposure data of NO₂ were collected and matched. Generalized mixed-effects models were used to analyze the associations between NO₂ and CKD, stratified by the presence of hypertension and taking antihypertensive medications. The stratified exposure-response curves of NO₂ and CKD were fitted using the natural spine smoothing function. The modifying effects of antihypertensive medications on the association and the exposure-response curve of NO₂ and CKD were analyzed.

RESULTS

Data of 45 136 participants were included, with an average age of (49.5±15.3) years. The annual average exposure concentration of NO₂ was (7.2±6.4) μg/m³. Altogether 6 517 (14.4%) participants were taking antihypertensive medications, and 4 833 (10.7%) participants were identified as having CKD. After adjustment for potential confounders, in the hypertension population not using antihypertensive medications, long-term exposure to NO₂ was associated with a significant increase risk of CKD (OR: 1.38, 95%CI: 1.24-1.54, P < 0.001); while in the hypertension population using antihypertensive medications, no significant association between long-term exposure to NO₂ and CKD (OR: 0.96, 95%CI: 0.86-1.07, P=0.431) was observed. The exposure-response curve of NO₂ and CKD suggested that there was a non-linear trend in the association between NO₂ and CKD. The antihypertension medications showed significant modifying effects both on the association and the exposure-response curve of NO₂ and CKD (interaction P < 0.001).

CONCLUSION

The association between long-term exposure to NO₂ and CKD was modified by antihypertensive medications. Taking antihypertensive medications may mitigate the effect of long-term exposure to NO₂ on CKD.

Maternal exposure to ambient particulate matter and green spaces and fetal renal function

Exposure to air pollution has been associated with different harmful effects and exposure to greenspace has been related to improved human health. However, the available evidence on the impact of these exposures on renal function is still scarce. The aim of this study was to determine the relationship between exposure to ambient levels of PM₁, PM_2.5, PM₁₀ and indicators of exposure to traffic as well as greenspace during pregnancy and fetal renal function based on the umbilical cord blood. This study was based on 150 pregnant women residing in Sabzevar, Iran (2018). Multiple linear regression models were developed to estimate the association of glomerular filtration rate (GFR), creatinine (Cr) and blood urea nitrogen (BUN) with exposure to air pollution, traffic, and greenspace (one at a time) controlled for relevant covariates. There was an inverse significant association between exposure to PM₁, PM_2.5, PM₁₀ and total street length in a 100 m buffer around the home and eGFR. Increase in distance to major road and residential surrounding greenness (100 m buffer) was associated with increase in eGFR. We observed a significant direct association between exposure to PMs as well as street length in 100 m buffer and serum level of Cr. There was also an inverse association between distance to major road and NDVI in 100 m buffer and Cr. The associations for blood urea nitrogen (BUN) were not statistically significant. Our results suggest that exposure to air pollution during pregnancy could have negative impact and exposure to greenspace could have positive impact on renal function of fetal.

A genome-wide by PM10 interaction study identifies novel loci for lung function near BICD1 and IL1RN-IL1F10 genes in Korean adults

Although several genome-wide interaction studies (GWIS) have been performed in specific European populations to understand the missing link between genetic and environmental factors for lung function, GWIS of Asian samples remain rare. Therefore, we performed a GWIS of exposure to air pollution to identify loci for lung function in Korean adult men. A total of 1826 adult men recruited from two health check-up centers were included in the analysis and the annual mean concentrations of ambient particulate matter with an aerodynamic diameter ≤10 μm (PM₁₀) were used. In case of forced vital capacity (FVC), one SNP (rs12312730) that passed our genome-wide threshold of pint < 1 × 10-5 was detected in the intronic region of the BICD1 gene on chromosome 12. In addition, we found two variants (rs6743376 and rs17042888) located near the IL1RN-IL1F10 gene that were involved in the inflammatory response and associated with decreased FVC via interaction with PM₁₀ exposure. A stratified association analysis according to these SNP genotypes showed that PM₁₀ concentrations in subjects with one or two of the risk alleles, compared with those with the non-risk allele, were significantly correlated with a reduction in FVC. This pattern was replicated in another 892 Korean adult samples. The current study reports the first GWIS discovery in an Asian population: the BICD1 and IL1RN-IL1F10 genes may contribute to the decrease in FVC levels by interacting with PM₁₀ exposure.

Interactions of CDH13 gene polymorphisms and ambient PM10 air pollution exposure with blood pressure and hypertension in Korean men

Associations between air pollution and blood pressure (BP) traits can be modified by several candidate genes, which might explain differences in individual genetic susceptibility. Based on recent evidence hypothesized to link air pollution and BP traits, we examined whether the polymorphisms of CDH13-a candidate gene-would modify the relationship between them in adult Korean men. A total of 1816 subjects were included. We divided them into two groups of high or low to moderate exposure using the annual average concentration of particulate matter with an aerodynamic diameter ≤10 μm (PM₁₀). We conducted an interaction analysis of PM₁₀ exposure using 200 single-nucleotide polymorphisms (SNPs), located within CDH13, in subjects with regard to BP traits and hypertension. The rs7500599 intronic SNP of CDH13 had the strongest signals for all BP traits including systolic blood pressure (SBP), diastolic blood pressure, and hypertension, by interacting with PM₁₀ exposure. An additional stratified analysis showed that the effects of PM₁₀ exposure on elevated BP and hypertension increased gradually in proportion to the number of minor alleles in this SNP. In addition, PM₁₀ exposure in the TT or GT genotype groups did not show significant associations with BP traits, whereas in a homozygous risk allele (GG) group, PM₁₀ exposure was significantly associated with BP traits and hypertension. For SBP, these patterns were reproducible at two independent sampling sites. This CDH13 polymorphism amplifies the negative associations of PM₁₀ exposure and elevated BP or hypertension in Korean men.

CYP1A1 gene polymorphisms modify the association between PM10 exposure and lung function

Genetic epidemiological studies have provided evidence that several genes modify the link between air pollution and lung function. We assessed whether the adverse impacts of particulate matter with an aerodynamic diameter ≤10 μm (PM₁₀) on lung function are modified by CYP1A1 gene polymorphisms in Korean adults. We used health check-up data from 1817 men, and the annual mean concentrations of ambient PM₁₀ estimated from the ambient data. Three single nucleotide polymorphisms (SNPs) of CYP1A1 were selected for our study. We identified significant CYP1A1 SNPs-by-PM₁₀ interactions for forced expiratory volume 1 s (FEV₁) and forced vital capacity (FVC) (all p_int < 0.05). Minor allele carriers of the SNPs were more susceptible to PM₁₀-induced FEV₁ and FVC reduction. The subgroup analysis of SNP genotypes showed that no significant association between PM₁₀ and FEV₁ or FVC was observed in homozygous reference genotype groups of all SNPs (all p_assoc > 0.05), whereas in heterozygous or homozygous alternate genotype groups, PM₁₀ was significantly associated with decreased FEV₁ (all p_assoc for FEV₁ < 0.05). The association between persistent exposure to PM₁₀ and lung function decline in Korean men may be determined in part by several functional variants of the CYP1A1 gene.

Genome-wide assessment of gene-by-smoking interactions in COPD

Cigarette smoke exposure is a major risk factor in chronic obstructive pulmonary disease (COPD) and its interactions with genetic variants could affect lung function. However, few gene-smoking interactions have been reported. In this report, we evaluated the effects of gene-smoking interactions on lung function using Korea Associated Resource (KARE) data with the spirometric variables—forced expiratory volume in 1 s (FEV₁). We found that variations in FEV₁ were different among smoking status. Thus, we considered a linear mixed model for association analysis under heteroscedasticity according to smoking status. We found a previously identified locus near SOX9 on chromosome 17 to be the most significant based on a joint test of the main and interaction effects of smoking. Smoking interactions were replicated with Gene-Environment of Interaction and phenotype (GENIE), Multi-Ethnic Study of Atherosclerosis-Lung (MESA-Lung), and COPDGene studies. We found that individuals with minor alleles, rs17765644, rs17178251, rs11870732, and rs4793541, tended to have lower FEV₁ values, and lung function decreased much faster with age for smokers. There have been very few reports to replicate a common variant gene-smoking interaction, and our results revealed that statistical models for gene-smoking interaction analyses should be carefully selected.

Association between exposure to ambient air pollution and renal function in Korean adults

Background

Ambient air pollution has a negative effect on many diseases, such as cardiovascular and respiratory diseases. Recent studies have reported a relationship between air pollution and renal function, but the results were limited to exposure to particulate matter (PM). This study was to identify associations between various air pollutants and renal function among Korean adults.

Methods

Nationwide survey data for a total of 24,407 adults were analyzed. We calculated the estimated glomerular filtration rate (eGFR) for each individual to assess their renal function and used this to categorize those with chronic kidney disease (CKD). To evaluate exposure to ambient air pollution, we used the annual mean concentrations of four ambient air pollutants: PM with an aerodynamic diameter ≤ 10 μm (PM₁₀), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and carbon monoxide (CO).

Results

We identified significant inverse relationships between the air pollutants PM₁₀ and NO₂ and eGFR in all statistical adjustment models (all p < 0.05). In the full covariate model, interquartile range increases in the annual mean concentrations of PM₁₀ and NO₂ were associated with decreases in eGFR levels of 0.46 (95% CI = − 0.87, − 0.04) and 0.85 (95% CI = − 1.40, − 0.30), respectively. Three of the ambient air pollutants were significantly related to an increased risk of CKD in the unadjusted model (p < 0.0001), but all significant associations disappeared after adjusting for covariates (all p > 0.05).

Conclusions

Exposures to PM₁₀ and NO₂ were significantly associated with decreases in eGFR levels, but not CKD, in Korean adults.