Association of blood mercury levels with nonmelanoma skin cancer in the U.S.A. using National Health and Nutrition Examination Survey data (2003-2016)

BACKGROUND

Some studies have reported increased incidence or mortality of lung and brain cancers associated with occupations involving potential mercury exposure. Epidemiological evidence related to skin cancer is also limited.

OBJECTIVES

To investigate the association between blood mercury (Hg) levels and nonmelanoma skin cancer (NMSC).

METHODS

We used National Health and Nutrition Examination Survey data from 2003 to 2016. The exposures were blood total (tHg), inorganic (iHg) and methylmercury (MeHg). The outcome was a self-reported diagnosis of NMSC. We included participants aged ≥ 20 years who had information on blood mercury and sociodemographic factors. We conducted a logistic regression analysis to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the risk of NMSC associated with quartiles of blood Hg, after adjusting for the sociodemographic factors and survey year.

RESULTS

The number of participants was 29 413; mean age was 49 years and 52% were female. Compared with those with a tHg ≤ 0·47 μg L^-1 (Q1), those with a tHg > 1·74 μg L^-1 (Q4) had nearly double the odds of NMSC (OR 1·79, 95% CI 1·19-2·71; P_trend = 0·004). Similarly, those in the highest quartile of MeHg (> 1·44 μg L^-1 ) had 1·7 times greater odds of NMSC (OR 1·74, 95% CI 1·13-2·70; P_trend = 0·01) than those in the lowest quartile (≤ 0·21 μg L^-1 ). iHg levels were nonsignificantly positively associated with NMSC (P_trend = 0·08).

CONCLUSIONS

We found that higher blood tHg and MeHg levels were associated with a higher prevalence of NMSC. Linked Comment: Taylor. Br J Dermatol 2020; 183:413-414.

Kerosene lighting contributes to household air pollution in rural Uganda

The literature on the contribution of kerosene lighting to indoor air particulate concentrations is sparse. In rural Uganda, kitchens are almost universally located outside the main home, and kerosene is often used for lighting. In this study, we obtained longitudinal measures of particulate matter 2.5 microns or smaller in size (PM_2.5 ) from living rooms and kitchens of 88 households in rural Uganda. Linear mixed-effects models with a random intercept for household were used to test the hypotheses that primary reported lighting source and kitchen location (indoor vs outdoor) are associated with PM_2.5 levels. During initial testing, households reported using the following sources of lighting: open-wick kerosene (19.3%), hurricane kerosene (45.5%), battery-powered (33.0%), and solar (1.1%) lamps. During follow-up testing, these proportions changed to 29.5%, 35.2%, 18.2%, and 9.1%, respectively. Average ambient, living room, and kitchen PM_2.5 levels were 20.2, 35.2, and 270.0 μg/m³ . Living rooms using open-wick kerosene lamps had the highest PM_2.5 levels (55.3 μg/m³ ) compared to those using solar lighting (19.4 μg/m³ ; open wick vs solar, P=.01); 27.6% of homes using open-wick kerosene lamps met World Health Organization indoor air quality standards compared to 75.0% in homes using solar lighting.

Cotton dust, endotoxin and cancer mortality among the Shanghai textile workers cohort: a 30-year analysis

BACKGROUND

Although occupational exposure to cotton dust and endotoxin is associated with adverse respiratory health, associations with cancer are unclear. We investigated cancer mortality in relation to cotton dust and endotoxin exposure in the Shanghai textile workers cohort.

METHODS

We followed 444 cotton textile and a reference group of 467 unexposed silk workers for 30 years (26 777 person-years). HRs for all cancers combined (with and without lung cancer) and gastrointestinal cancer were estimated in Cox regression models as functions of cotton textile work and categories of cumulative exposure (low, medium, high), after adjustment for covariates including pack-years smoked. Different lag years accounted for disease latency.

RESULTS

Risks of mortality from gastrointestinal cancers and all cancers combined, with the exclusion of lung cancer, were increased in cotton workers relative to silk workers. When stratified by category of cumulative cotton exposure, in general, risks were greatest for 20-year lagged medium exposure (all cancers HR=2.7 (95% CI 1.4 to 5.2); cancer excluding lung cancer HR=3.4 (1.7-7.0); gastrointestinal cancer HR=4.1 (1.8-9.7)). With the exclusion of lung cancer, risks of cancer were more pronounced. When stratified by category of cumulative endotoxin exposure, consistent associations were not observed for all cancers combined. However, excluding lung cancer, medium endotoxin exposure was associated with all cancers and gastrointestinal cancer in almost all lag models.

CONCLUSIONS

Cotton dust may be associated with cancer mortality, especially gastrointestinal cancer, and endotoxin may play a causative role. Findings also indirectly support a protective effect of endotoxin on lung cancer.

Cancer mortality among Chinese chrysotile asbestos textile workers

To determine mortality associated with exposure to chrysotile asbestos, a cohort of asbestos workers from an asbestos textile factory in China was followed prospectively from 1972 to 2008. A total 577 workers were successfully followed, achieving a follow-up rate of 98.5% over 37 years. Employment data and smoking information were obtained from factory and individual workers. Vital status was ascertained from factory personnel records and the municipal death registry. Workers were categorized into high, medium and low exposure groups in terms of their job titles and workshops. Follow-up generated 17,508 person-years, with 259 deaths from all causes, 96 all cancers and 53 lung cancers and 2 mesotheliomas. The highest cancer mortality was observed in the high exposure group, with 1.5-fold age-adjusted mortality from all cancers and 2-fold from lung cancer compared to the low exposure group. Age and smoking adjusted hazard ratio in the high exposure group was 2.99 (95%CI, 1.30, 6.91) for lung cancer and 2.04 (1.12, 3.71) for all cancers. Both smokers and nonsmokers at the high exposure level had a high death risk of lung cancer, with a clearer exposure-response trend seen in smokers. This study confirmed increased mortality from lung cancer and all cancers in asbestos workers, and the cancer mortality was associated with exposure level.

Genetic variants associated with severe pneumonia in A/H1N1 influenza infection

The A/H1N1 influenza strain isolated in Mexico in 2009 caused severe pulmonary illness in a small number of exposed individuals. Our objective was to determine the influence of genetic factors on their susceptibility. We carried out a case-control association study genotyping 91 patients with confirmed severe pneumonia from A/H1N1 infection and 98 exposed but asymptomatic household contacts, using the HumanCVD BeadChip (Illumina, San Diego, CA, USA). Four risk single-nucleotide polymorphisms were significantly (p<0.0001) associated with severe pneumonia: rs1801274 (Fc fragment of immunoglobulin G, low-affinity IIA, receptor (FCGR2A) gene, chromosome 1; OR 2.68, 95% CI 1.69-4.25); rs9856661 (gene unknown, chromosome 3; OR 2.62, 95% CI 1.64-4.18); rs8070740 (RPA interacting protein (RPAIN) gene, chromosome 17; OR 2.67, 95% CI 1.63-4.39); and rs3786054 (complement component 1, q subcomponent binding protein (C1QBP) gene, chromosome 17; OR 3.13, 95% CI 1.89-5.17). All SNP associations remained significant after adjustment for sex and comorbidities. The SNPs on chromosome 17 were in linkage disequilibrium. These findings revealed that gene polymorphisms located in chromosomes 1 and 17 might influence susceptibility to development of severe pneumonia in A/H1N1 infection. Two of these SNPs are mapped within genes (FCGR2A, C1QBP) involved in the handling of immune complexes and complement activation, respectively, suggesting that these genes may confer risk due to increased activation of host immunity.

Body mass index is associated with the development of acute respiratory distress syndrome

BACKGROUND

The relationship between body mass index (BMI) and development of acute respiratory distress syndrome (ARDS) is unknown.

METHODS

A cohort study of critically ill patients at risk for ARDS was carried out. BMI was calculated from admission height and weight. Patients were screened daily for AECC (American European Consensus Committee)-defined ARDS and 60-day ARDS mortality.

RESULTS

Of 1795 patients, 83 (5%) patients were underweight (BMI <18.5 kg/m(2)), 627 (35%) normal (BMI 18.5-24.9), 605 (34%) overweight (BMI 25-29.9), 364 (20%) obese (BMI 30-39.9) and 116 (6%) severely obese (BMI > or =40). Increasing weight was associated with younger age (p<0.001), diabetes (p<0.0001), higher blood glucose (p<0.0001), lower prevalence of direct pulmonary injury (p<0.0001) and later development of ARDS (p = 0.01). BMI was associated with ARDS on multivariate analysis (OR(adj) 1.24 per SD increase; 95% CI 1.11 to 1.39). Similarly, obesity was associated with ARDS compared with normal weight (OR(adj) 1.66; 95% CI 1.21 to 2.28 for obese; OR(adj) 1.78; 95% CI 1.12 to 2.92 for severely obese). Exploratory analysis in a subgroup of intubated patients without ARDS on admission (n = 1045) found that obese patients received higher peak (p<0.0001) and positive end-expiratory pressures (p<0.0001) than non-obese patients. Among patients with ARDS, increasing BMI was associated with increased length of stay (p = 0.007) but not with mortality (OR(adj) 0.89 per SD increase; 95% CI 0.71 to 1.12).

CONCLUSION

BMI was associated with increased risk of ARDS in a weight-dependent manner and with increased length of stay, but not with mortality. Additional studies are needed to determine whether differences in initial ventilator settings may contribute to ARDS development in the obese.

Circulating adhesion molecules after short-term exposure to particulate matter among welders

BACKGROUND

Studies from several countries indicate that welders experience increased risk of mortality and morbidity from ischaemic heart disease. Although the underlying mechanisms are unclear, vascular responses to particulate matter contained in welding fumes may play a role. To investigate this, we studied the acute effects of welding fume exposure on the endothelial component of vascular function, as measured by circulating adhesion molecules involved in leukocyte adhesion (sICAM-1 and sVCAM-1) and coagulation (vWF).

METHODS

A panel of 26 male welders was studied repeatedly across a 6 h work-shift on a high exposure welding day and/or a low exposure non-welding day. Personal PM(2.5) exposure was measured throughout the work-shift. Blood samples were collected in the morning (baseline) prior to the exposure period, immediately after the exposure period, and the following morning. To account for the repeated measurements, we used linear mixed models to evaluate the effects of welding (binary) and PM(2.5) (continuous) exposure on each blood marker, adjusting for baseline blood marker concentration, smoking, age and time of day.

RESULTS

Welding and PM(2.5) exposure were significantly associated with a decrease in sVCAM-1 in the afternoon and the following morning and an increase in vWF in the afternoon.

CONCLUSIONS

The data suggest that welding and short-term occupational exposure to PM(2.5) may acutely affect the endothelial component of vascular function.

Comparison of squamous cell carcinoma and adenocarcinoma of the lung by metabolomic analysis of tissue-serum pairs

The prospect of establishing serum metabolomic profiles offers great clinical significance for its potential to detect human lung cancers at clinically asymptomatic stages. Patients with suspicious serum metabolomic profiles may undergo advanced radiological tests that are too expensive to be employed as screening tools for the mass population. As the first step to establishing such profiles, this study investigates correlations between tissue and serum metabolomic profiles for squamous cell carcinoma (SCC) and adenocarcinoma (AC) in the lungs of humans. Tissue and serum paired samples from 14 patients (five SCCs and nine ACs), and seven serum samples from healthy controls were analyzed with high-resolution magic angle spinning proton magnetic resonance spectroscopy (HRMAS (1)HMRS). Tissue samples were subjected to quantitative histological pathology analyses after MRS. Based on pathology results, tissue metabolomic profiles for the evaluated cancer types were established using principal component and canonical analyses on measurable metabolites. The parameters used to construct tissue cancer profiles were then tested with serum spectroscopic results for their ability to differentiate between cancer types and identify cancer from controls. In addition, serum spectroscopic results were also analyzed independent of tissue data. Our results strongly indicate the potential of serum MR spectroscopy to achieve the task of differentiating between the tested human lung cancer types and from controls.

Serum bilirubin levels on ICU admission are associated with ARDS development and mortality in sepsis

BACKGROUND

Hyperbilirubinaemia is a common complication of sepsis. Elevated bilirubin may induce inflammation and apoptosis. It was hypothesised that increased serum bilirubin on Intensive Care Unit (ICU) admission contributes to sepsis-related acute respiratory distress syndrome (ARDS).

METHODS

Serum bilirubin on ICU admission was measured in 1006 patients with sepsis. Serial serum bilirubin was analysed prospectively in patients with sepsis who had ARDS for a period of 28 days. The effects of clinical factors and variants of the UGT1A1 gene on serum bilirubin levels were determined. Outcomes were ARDS risk and mortality.

RESULTS

During 60-day follow-up, 326 patients with sepsis developed ARDS, of whom 144 died from ARDS. The hyperbilirubinaemia (>or=2.0 mg/dl) rate in patients with ARDS (22.4%) was higher than in those without ARDS (14.1%, p = 0.002). For each 1.0 mg/dl increase in admission bilirubin, ARDS risk and 28- and 60-day ARDS mortalities were increased by 7% (OR = 1.07; p = 0.003), 20% (OR = 1.20; p = 0.002) and 18% (OR = 1.18; p = 0.004), respectively. Compared with subjects with bilirubin levels <2.0 mg/dl, patients with hyperbilirubinaemia had higher risks of ARDS (OR = 2.12; p = 0.0007) and 28-day (OR = 2.24; p = 0.020) and 60-day ARDS mortalities (OR = 2.09; p = 0.020). In sepsis-related ARDS, serial bilirubin levels in non-survivors were consistently higher than in survivors (p<0.0001). Clinical variables explained 29.5% of the interindividual variation in bilirubin levels, whereas genetic variants of UGT1A1 contributed 7.5%.

CONCLUSION

In sepsis, a higher serum bilirubin level on ICU admission is associated with subsequent ARDS development and mortality.

Sex-specific association of epidermal growth factor gene polymorphisms with acute respiratory distress syndrome

Epidermal growth factor (EGF) is involved in alveolar epithelial repair, lung fluid clearance and inflammation, and is regulated by sex hormones. An unmatched, nested case-control study was conducted to evaluate the associations of EGF variants with acute respiratory distress syndrome (ARDS) and the role of sex on the associations between EGF variants and ARDS. Patients with ARDS risk factors upon intensive care unit admission were enrolled. Cases were 416 Caucasians who developed ARDS and controls were 1,052 Caucasians who did not develop ARDS. Cases were followed for clinical outcomes and 60-day mortality. One functional single nucleotide polymorphism (SNP), rs4444903, and six haplotype-tagging SNPs spanning the entire EGF gene were genotyped. No individual SNP or haplotype was associated with ARDS risk or outcomes in all subjects. Sex-stratified analyses showed opposite effects of EGF variants on ARDS in males versus in females. SNPs rs4444903, rs2298991, rs7692976 and rs4698803, and haplotypes GGCGTC and ATCAAG were associated with ARDS risk in males. No associations were observed in females. Interaction analysis showed that rs4444903, rs2298991, rs7692976 and rs6533485 significantly interacted with sex for ARDS risk. The present study suggests that associations of epidermal growth factor gene variants with acute respiratory distress syndrome risk are modified by sex. The current findings should be replicated in other populations.

Polymorphisms inGSTT1andp53and urinary transitional cell carcinoma in south-western Taiwan: A preliminary study

Little is known about the relevance of genetic polymorphisms to arsenic-related bladder cancer. A preliminary case-control study was conducted to explore the association between genetic polymorphisms of GSTT1, p53 codon 72 and bladder cancer in southern Taiwan, a former high arsenic exposure area. Fifty-nine urinary transitional cell carcinoma (TCC) patients from a referral centre in south-western Taiwan and 81 community controls matched on residence were recruited from 1996 to 1999. A questionnaire was administered to obtain arsenic exposure and general health information. Genotypes of p53 codon 72 and GSTT1 were analysed by polymerase chain reaction-restriction fragment length polymerase. The combined variant genotypes (heterozygous or homozygous variant) of p53 codon 72 and GSTT1 null were observed in 29% of cases and in 44% of controls, respectively. In this preliminary study, bladder cancer risk was slightly elevated for subjects carrying the variant genotype of p53 codon 72 or in subjects carrying the GSTT1 null genotype. Variants in p53 codon 72 increased the risk of bladder cancer among smokers. However, the results were not statistically significant and larger confirmatory studies are needed to clarify the role of candidate gene polymorphisms and bladder cancer risk in arsenic exposed populations.

Genetic susceptibility to occupational exposures

Because of their high prevalence in the general population, genetic variants that determine susceptibility to environmental exposures may contribute greatly to the development of occupational diseases in the setting of specific exposures occurring in the workplace. Studies investigating genetic susceptibilities in the workplace may: (1) provide mechanistic insight into the aetiology of disease, in particular the determination of environmentally responsive genes; (2) identify susceptible subpopulations with respect to exposure; and (3) provide valuable input in setting occupational exposure limits by taking genetic susceptibility into account. Polymorphisms in the NAT2 and the HLA-DPB1(G)(lu69) genes provide classic examples of how genetic susceptibility markers have a clear role in identifying disease risk in bladder cancer and chronic beryllium disease, respectively. For diseases with more complex and multifactorial aetiology such as occupational asthma and chronic airways disease, susceptibility studies for selected genetic polymorphisms provide additional insight into the biological mechanisms of disease. Even when polymorphisms for genetic susceptibility have a clear role in identifying disease risk, the value of wide scale genetic screening in occupational settings remains limited due to primarily ethical and social concerns. Thus, large scale genetic screening in the workplace is not currently recommended.

Polymorphisms of inflammatory and metalloproteinase genes, Helicobacter pylori infection and the risk of oesophageal adenocarcinoma

Helicobacter pylori (HP) infection appears protective against oesophageal adenocarcinoma (EA) risk. Matrix metalloproteinases (MMPs) are released in the presence of HP infection. In MMP2 wild-type individuals, HP was significantly protective of EA risk (adjusted odds ratio: 0.29; 95% confidence interval=0.1-0.7). Matrix metalloproteinases may modulate the EA-HP relationship.

Matrix metalloproteinase 2 (MMP2) polymorphism, Helicobacter pylori (HP) infection and esophageal adenocarcinoma (EA) risk

10553

Background: Epidemiologic studies suggest that HP infection protects against EA risk, as HP-mediated chronic atrophic gastritis reduces acid reflux. Genetic variations may modify the host response to HP infection and alter this risk. MMP2 expression is commonly upregulated in HP infections. We hypothesize that a functional MMP2 promoter polymorphism (-C1306T) that abolishes a Sp1 binding site and decreases promoter activity will also reduce the protective effects of HP infections in EA risk. Methods: HP status was determined in 98 EA patients and 101 age and gender matched healthy controls, using a commercially available serum immunoblotting kit (Helicoblot 2.1, Genelabs Diagnostics) that measures ever, current, CagA+ and VacA+ HP infections. Genotyping was performed using TaqMan. Data were analyzed using unconditional logistic regression. Results: 39% of cases and 44% of controls (P=0.69) had MMP2 variants (T/T or C/T). 36% of cases and 42% of controls were ever HP infected (P= 0.35). In individuals carrying the MMP2 wild type (CC) genotype, ever HP infection was strongly protective against EA [Odds Ratio (OR) 0.32: 95% CI, 0.13–0.75; P=0.008]. In contrast, in individuals carrying the MMP2 variants that are associated with lower promoter activity, this protective effect was lost (OR 1.76; 95% CI, 0.06–5.2; P= 0.30). Similar results were found when evaluating the MMP2 and current, CagA or VacA infection. Statistical interactions between MMP2 genotype and ever HP infection (P=0.027) and between MMP2 genotype and VacA+ infection (P= 0.035) were significant. Conclusions: We are the first to report that host factors such as the MMP2 polymorphism modulate the role of HP infection in EA susceptibility.

No significant financial relationships to disclose.

Stage and histology influence the relationship between MDM2 promoter polymorphism and esophageal cancer and overall survival (OS)

21047

Background: A single nucleotide polymorphism in the MDM2 promoter (SNP309) has been found to affect OS of advanced stage gastric adenocarcinoma (AD) and early stage squamous (SQ) cell carcinoma of the lung. The aim of this study was to evaluate the role of this polymorphism in the prognosis of esophageal cancer, another aerodigestive cancer. Methods: 150 early stage (E) and 118 locally advanced stage (LA) esophageal cancers were genotyped for MDM2 SNP309 using Taqman. The primary endpoint was overall survival (OS). Results: E disease: n=23 stage I; n=127 stage II. LA disease: n=93, Stage III; n=25, Stage IVA. AD comprised 215 (81%), while SQ comprised 45 (17%) of cases; 8 (3%) had poorly differentiated tumors. Median follow-up = 32 months. Median OS were 36 and 21 months for E and LA disease, respectively. Both histology and disease stage affected the relationship between SNP309 and esophageal cancer OS (see Table ). The wildtype T/T genotype conferred a worse OS in E patients (log-rank, p=0.03), especially those with AD (log-rank, p=0.003). In Cox proportional hazards interaction analyses, after adjusting for age, gender, stage and PS, there were statistically significant interactions between MDM2 SNP309 and disease stage (interaction p=0.004) and between MDM2 SNP309 and histologic subtype (AD vs. SQ)(interaction p=0.02). Thus, the direction of SNP309 association from our AD and E esophageal cancer patients are opposite to those of our SQ and LA esophageal cancer patients. However, our SQ and LA results are similar to the SQ lung cancer and advanced stage gastric cancers previously reported. This suggests that biologic mechanisms underpinning the prognostic role of SNP309 are dependent on extent of disease and histologic subtype. Conclusion: Histology and disease stage interact with the prognostic role of MDM2 SNP309 polymorphism in esophageal cancer OS.

[Table: see text]

No significant financial relationships to disclose.

Prognostic significance of nuclear excision (NER) and base excision (BER) DNA repair gene polymorphisms in esophageal cancer

2511

Background: DNA repair pathways are involved in cisplatin-induced damage (NER pathway) & radiation damage (BER pathway). Some single nucleotide polymorphisms (SNPs) of DNA repair genes are associated with DNA repair capacity, cancer risk & outcomes. We investigated the prognostic significance of 7 NER/BER SNPs on disease free (DFS) & overall survival (OS) in esophageal cancer. Methods: 150 patients with esophageal cancer treated with cisplatin-based chemoradiation & surgery were genotyped for BER (XRCC1 Arg399Gln; APE1 Asp148Glu; hOGG1 Ser326Cys) & NER (ERCC1 8092C/A; ERCC1 codon 118 C/T; XPD Asp312Asn; XPD Lys751Gln) SNPs. Analysis involved Kaplan-Meier curves, log-rank tests, and Cox proportional hazards models. Results: Median age: 63 years (range 28–80); 91% male; 100% ECOG performance status (PS) 0–1; adenocarcinoma 79%; stages IIA 22%, IIB 30%, III 33%, and IVA 15%. No SNPs were associated with stage or PS. Multiple NER SNP was independently prognostic for OS and DFS (see Table ). When compared to individuals who were wildtype in all four studied NER SNPs, individuals with variants in all four NER SNPs were associated with substantial improvement in OS (Adjusted Hazard Ratio (AHR) = 0.40, 95% confidence interval (CI) = 0.2–0.7) and DFS (AHR = 0.44, 95%CI = 0.2–0.8). Furthermore, increasing numbers of variant genotypes were associated with a progressive increase in OS & DFS when all seven NER/BER pathway SNPs were analysed together ( Table ). There was a 3.8- fold increase in OS (75 vs. 20 months) and five-fold increase in DFS (51 vs. 10 months) when comparing individuals with 6–7 SNPs with variant alleles to individuals with 0–1 SNPs with variant alleles. Conclusions: The ERCC1 8092 C/A, XPD Asp312Asn & XPD Lys751Gln SNPs in the NER pathway are associated individually with prognosis in esophageal cancer patients treated with cisplatin-based trimodality regimens. In addition, as the number of NER and BER SNPs carrying variant alleles increased, OS and DFS improved dramatically.

[Table: see text]

No significant financial relationships to disclose.

MMP1 1G/2G promoter polymorphism and risk of esophageal adenocarcinoma

10555

Background: The 2G allele of the MMP1 -1607 1G/2G promoter polymorphism creates an Ets binding site that leads to increased transcriptional and enzyme activity, particularly in the presence of growth factors and cytokines. This polymorphism has been associated with greater risk of cancer (e.g., renal cell, lung and oral cancers, glioblastomas) and cancer invasiveness (e.g., melanoma, cervical, lung and colorectal cancer). The aim of the current study was to evaluate the role of this MMP 1G/2G polymorphism in the risk of esophageal adenocarcinoma (EA). Methods: We evaluated 323 histologically confirmed EA cases and 464 healthy controls frequency-matched for age and gender. Genotyping of the MMP1 1G/2G promoter polymorphism involved a Taqman approach. All EAs had endoscopic evidence showing that the center of the tumors were located at or above the gastroesophageal junction. Odds Ratios (OR) were calculated using multivariate logistic regression, adjusted for age, gender, smoking status, and body-mass index (BMI) at the age of 18 years (to represent a healthy adult BMI). Results: Genotype frequencies were: 33% (1G/1G), 47% (1G/2G) & 20% (2G/2G) in controls; in cases, 26% (1G/1G), 50% (1G/2G) & 24% (2G/2G). 88% of cases were male. The MMP1 2G/2G and 1G/2G genotypes conferred a greater risk of EA, with adjusted ORs of 1.50 (95%CI=1.0–2.3) and 1.34 (95%CI=0.9–1.9), respectively, when compared with the wildtype 1G/1G genotype. The 2G allele (2G/2G + 1G/2G) conferred an adjusted OR of 1.38 (95%CI=1.0–1.9). By stage, the adjusted ORs for the 2G allele were 1.26 (95%CI=0.8–2.1), 1.45 (95%CI=0.9–2.3), & 1.54 (95%CI=0.9–2.7) for node negative, node-positive, and metastatic disease, respectively. Conclusions: The 2G allele of the MMP1 -1607 1G/2G polymorphism was associated with an increased risk of EA in this analysis. In addition, there was a non-significant trend towards conferring greater risk in the more advanced stages of EA, suggesting a possible role of this polymorphism in the invasiveness of this cancer.

No significant financial relationships to disclose.

Epidermal growth factor receptor polymorphisms and clinical outcomes in non-small-cell lung cancer patients treated with gefitinib

The-216G/T, -191C/A, intron 1 and Arg497Lys epidermal growth factor receptor (EGFR) polymorphisms were evaluated in 92 advanced non-small-cell lung cancer patients treated with gefitinib, an EGFR tyrosine-kinase inhibitor. Improved progression free survival (PFS) was found in patients homozygous for the shorter lengths of intron 1 polymorphism (S/S; S=16 or fewer CA repeats; log-rank test (LRT) P=0.03) and for patients carrying any T allele of the -216G/T polymorphism (LRT, P=0.005). When considered together, patients with intron 1 S/S genotype and at least one T allele of -216G/T had improved PFS (LRT P=0.0006; adjusted hazard ratio (AHR), 0.60 (95% confidence interval, 0.36-0.98)) and overall survival (LRT P=0.02; AHR, 0.60 (0.36-1.00)) when compared with all others. The T allele of -216G/T was also associated with significantly higher rates of stable disease/partial response (P=0.01) and a significantly higher risk of treatment-related rash/diarrhea (P=0.004, multivariate model). EGFR intron 1 and -216G/T polymorphisms influence clinical outcomes in gefitinib-treated non-small-cell lung cancer patients.

Genotypes and haplotypes of the VEGF gene are associated with higher mortality and lower VEGF plasma levels in patients with ARDS

BACKGROUND

Endothelial injury is an important prognostic factor in acute respiratory distress syndrome (ARDS). Vascular endothelial growth factor (VEGF) plays a critical role in endothelial destruction and angiogenesis. Genetic variations of the VEGF gene have been associated with VEGF production. A study was undertaken to investigate the impact of VEGF gene polymorphisms on the clinical outcomes of ARDS.

METHODS

Three VEGF polymorphisms (-460C/T, +405C/G and +936C/T) were determined in 1253 patients in an intensive care unit with risk factors for ARDS, 394 of whom developed ARDS. Patients were followed for assessment of 60 day survival. Plasma VEGF levels were measured in 71 patients with ARDS.

RESULTS

The +936TT (OR 4.29, 95% CI 1.12 to 16.40, p = 0.03) and +936CT+TT (OR 1.98, 95% CI 1.14 to 3.42, p = 0.01) genotypes were significantly associated with increased mortality from ARDS. Plasma VEGF levels in patients with ARDS with the +936CT+TT genotype were significantly lower than in subjects with the +936CC genotype (median 49 (IQR 16-98) pg/ml vs 112 (IQR 47-162) pg/ml, p = 0.02). At the haplotype level, haplotype TCT (-460T+405C+936T) was significantly associated with a higher rate of mortality (OR 2.89, 95% CI 1.30 to 6.43, p = 0.009) and haplotype CGT (-460C+405G+936T) was associated less strongly with increased mortality (OR 1.90, 95% CI 0.94 to 3.83, p = 0.07) in patients with ARDS. Lower plasma VEGF levels were correlated with the probability of haplotype CGT (coefficient = -0.26, p<0.05), but the same trend of correlation was not significant to haplotype TCT.

CONCLUSIONS

VEGF polymorphisms may contribute to the prognosis and inter-individual variations in circulating VEGF levels in patients with ARDS.

MDM2 polymorphism and recurrence-free and overall survival in early stage non-small cell lung cancer (NSCLC)

7221

Background: MDM2 is a negative regulator of p53. A T->G polymorphism in the promoter region of MDM2 has been described, where the G/G genotype is associated with higher MDM2 mRNA and protein levels. Overexpression of MDM2 is thought to interfere with p53-mediated apoptosis and growth inhibition, leading to cancer progression. We hypothesized that the MDM2 G/G genotype may be associated with worse survival outcomes in early stage lung cancer. Methods: We evaluated the relationship between MDM2 polymorphism status and overall survival (OS) and recurrence-free survival (RFS) among 385 Stage I and II NSCLC patients treated with surgical resection at Massachusetts General Hospital from 1992 to 2000. The MDM2 polymorphism was genotyped using the 5’-nuclease assay (Taqman). Kaplan-Meier methods and the log-rank test were used to compare survival by polymorphism status. Cox proportional hazards models were used to adjust for possible confounding variables. Results: Median age was 69, and 48% were female. 52% were Stage IA, 29% Stage IB, 4% Stage IIA, and 15% Stage IIB. 49% had adenocarcinoma, 29% squamous cell, 12% BAC, and 10% other NSCLC. The genotype frequencies for the MDM2 polymorphism were: T/T 161 (42%), T/G 156 (40%), G/G 68 (18%). Genotype was not associated with age, sex, stage, histology, or smoking status. Median follow-up time was 5.79 years. After adjusting for age, sex, stage, histology, and pack-yrs of smoking, the G/G genotype appeared to be associated with worse RFS and OS (AHR 1.60 (95% CI 1.10–2.34), p = 0.01; AHR 1.56 (95% CI 1.03–2.38), p = 0.04; respectively). In subset analysis, patients with squamous cell cancer and current-smokers had significantly worse survival with the G/G genotype, while there was no significant difference by genotype among adenocarcinomas and non-current smokers. (For squamous cell, 5-yr OS for T/T 59%, T/G 52%, G/G 7%, p = 0.0001; for current smokers, 5-yr OS for T/T 67%, T/G 49%, G/G 27%, p = 0.04). Conclusions: Our findings suggest that the G/G genotype of the MDM2 polymorphism is associated with worse survival among early stage NSCLC patients, particularly those with squamous cell histology and current smokers. Supported by NIH grants CA074386, CA092824, CA090578, FAMRI Young Clinical Scientist Award, Doris Duke Foundation.

[Table: see text]

Long driving time is associated with haematological markers of increased cardiovascular risk in taxi drivers

AIMS

To examine the association between driving time and changes in haematological markers of increased risks for cardiovascular diseases (CVD).

METHODS

The authors conducted a cross sectional analysis of baseline data from the Taxi Drivers' Health Study cohort in Taipei, Taiwan. They retrieved information on comorbidity, laboratory tests, age, and anthropometric measures from medical records of 1157 subjects (mean age 44.6 (SD 8.6) years). Whole blood cell (WBC) count was used as the primary haematological marker for increased CVD risk, and platelet count and haematocrit as the secondary markers. Standardised questionnaires were implemented to collect information on demographics, lifestyle, work related physical and psychosocial factors, and driving time profiles. Multiple regression was used to estimate the adjusted effects of driving time on three haematological markers.

RESULTS

The mean measured hematological marker was 6656 (SD 1656) cells x10(6)/l for WBC, 47.2 (SD 3.5) % for hematocrit, and 243 (SD 52) cells x10(9)/l for platelets. The driving time was 264 (SD 76) hours/month. Compared with drivers who drove < or =208 hours/month (1st quartile cut off), drivers who drove >208 hours/month had a higher WBC count (by 317 x10(6)/l; 95% CI 99 to 535), haematocrit (by 0.8%; 95% CI 0.3 to 1.2), and platelets (7.9 x10(9)/l; 95% CI 1.0 to 14.8). After adjusting for conventional CVD risk factors (age, sex, smoking, hypertension, diabetes, and hypercholesterolaemia), obesity, alcohol drinking, regular exercise, and sociodemographics (education, marital status, income, and so on), long driving time was still associated with significant increases in WBC and platelets, whereas the effect on haematocrit was diminished and became statistically non-significant. Additional controls for physical workload, self-perceived job stress, and job dissatisfaction did not alter the associations with increased WBC and platelets.

CONCLUSIONS

Longitudinal studies are needed to confirm the observed cross sectional association and to further examine the specific occupational exposures accountable for the association between driving time and haematological markers of systemic inflammation and haemostatic alteration.

A 20-year follow-up study on chronic respiratory effects of exposure to cotton dust

In order to evaluate chronic effects of long-term exposure to cotton dust on respiratory health, and the role of dust and endotoxin, longitudinal changes in lung function and respiratory symptoms were observed prospectively from 1981 to 2001 in 447 cotton textile workers, along with 472 silk textile controls. The results from five surveys conducted over the 20-yr period are reported, including standardised questionnaires, pre- and post-shift spirometric measurements, work-area inhalable dust sample collections and airborne Gram-bacterial endotoxin analysis. Cotton workers had more persistent respiratory symptoms and greater annual declines in forced expiratory volume in one second (FEV1) and forced vital capacity as compared with silk workers. After exposure cessation, in the final 5-yr period, the rate of FEV1 decline tended to slow in nonsmoking males, but not in nonsmoking females. Workers who reported byssinotic symptoms more persistently suffered greater declines in FEV1. Chronic loss in lung function was more strongly associated with exposure to endotoxin than to dust. In conclusion, the current study suggests that long-term exposure to cotton dust, in which airborne endotoxin appears to play an important role, results in substantial adverse chronic respiratory effects.

−308GAandTNFBpolymorphisms in acute respiratory distress syndrome

The -308GA and TNFB1/2 polymorphisms of the tumour necrosis factor genes have been associated with increased susceptibility to, and mortality in sepsis, although, prior studies are not consistent. Their role in acute respiratory distress syndrome (ARDS) has not been evaluated. The current authors hypothesised that the -308A allele and TNFB22 genotype would be associated with increased susceptibility to, and mortality in ARDS. The above hypothesis was investigated in a nested case-control study of 441 Caucasian controls and 212 cases admitted to an intensive care unit with sepsis, trauma, aspiration or hyper-transfusions. The -308A and TNFB1 alleles were in linkage disequilibrium. These polymorphisms were not associated with ARDS susceptibility on crude analysis. On subgroup analyses, they were associated with either increased or decreased odds of developing ARDS depending on whether the clinical risk for ARDS results in direct or indirect pulmonary injury. The -308A allele was associated with increased 60-day mortality in ARDS, with the strongest association found among younger patients. There was no association between the TNFB polymorphism and ARDS mortality. The -308GA, but not the TNFB12, polymorphism was associated with increased mortality in acute respiratory distress syndrome, but their association with acute respiratory distress syndrome susceptibility depended on the site of injury predisposing to acute respiratory distress syndrome.

Exposure to welding fumes is associated with acute systemic inflammatory responses

AIMS

To investigate the acute systemic inflammatory response to welding fume exposure.

METHODS

Twenty four welders (42% smokers) and 13 non-exposed controls (23% smokers) were monitored at a welding school. Exposure to fine particulate matter (PM2.5) was assessed using cyclone samplers. Markers of systemic inflammation, including C-reactive protein (CRP), fibrinogen, and white blood cell (WBC) levels, were determined in peripheral blood samples collected at baseline and after 5.3 (SD 1.0) hours of exposure.

RESULTS

The median PM2.5 concentration for welders was 1.66 mg/m3, which was significantly greater than that for controls (0.04 mg/m3). Compared to non-smokers, smokers had a significantly higher baseline WBC count, but comparable levels of CRP and fibrinogen. In non-smokers, welding fume exposure was associated with a significant increase in WBC and neutrophil counts immediately following exposure (+0.8x10(3)/mul, 95% CI 0.1 to 1.6, and +1.0x10(3)/mul, 95% CI 0.4 to 1.7, respectively). A significant decrease in fibrinogen levels was observed in non-smokers (-32 mg/dl, 95% CI -63 to -1). No significant changes in WBC, neutrophil, and fibrinogen levels were found in smokers. Sixteen hours after welding exposure, CRP levels were found to be significantly increased in both non-smokers and smokers (0.90 mg/l, 95% CI 0.17 to 1.64). PM2.5 concentrations were found to be significantly associated with absolute neutrophil counts in non-smokers, and CRP levels in both non-smokers and smokers.

CONCLUSIONS

High levels of welding fume exposure induce acute systemic inflammation in a relatively young, healthy working population. These results also suggest that smoking may modify the effect of welding fume exposure on specific inflammatory markers.

Occupational and personal factors associated with acquired lumbar spondylolisthesis of urban taxi drivers

AIMS

To investigate the occupational and personal factors associated with lumbar spondylolisthesis in taxi drivers.

METHODS

Cross-sectional analysis of the baseline data from the Taxi Drivers' Health Study cohort. Information was retrieved from the medical records of standardised lumbosacral spine plain films, age, and anthropometric measures of 1242 subjects. Acquired spondylolisthesis (ASL) was defined as non-lytic spondylolisthesis involving lumbar spines above L5. Questionnaires were used to gather information on demographic features, health behaviours, exercise, work related physical and psychosocial factors, and driving time profiles. Multiple logistic regression was used to model the odds ratio (OR) for prevalent ASL cases associated with personal and occupational factors.

RESULTS

A total of 40 cases (3.2%) of ASL were diagnosed. Among those driving < or =5 years, 6-15 years, and >15 years, the estimated prevalence of lumbar spondylolisthesis was 1.1%, 2.4%, and 7.1% respectively. Results of multiple logistic regression suggested that taxicab driving >15 years (OR = 3.4, 95% CI 1.1 to 10.7, compared to driving < or =5 years), age (OR = 2.6, 95% CI 1.1 to 6.6 for age 46-55; and OR = 4.8, 95% CI 1.8 to 12.9 for age >55), body mass index > or =25 kg/m2 (OR = 2.2, 95% CI 1.1 to 4.6), and frequent strenuous exercise (OR = 2.2, 95% CI 1.1 to 4.5) were significantly associated with higher prevalence of spondylolisthesis. There was a consistent likely exposure-response relation between professional seniority and ASL prevalence.

CONCLUSIONS

Longitudinal studies are needed to confirm the observed association between professional driving and spondylolisthesis, and to examine further the specific occupational exposures accountable for this association.

Hormesis: the new approach in risk assessment?

Hormesis is a dose-response phenomenon characterized by either a U-shaped or an inverted U-shaped dose response depending on the different end points measured. In a paper in this issue of the journal, Drs Jayjock and Lewis advocate for the application of hormesis in the field of industrial hygiene, and suggest the use of hormesis as a default assumption in the risk assessment process. However, there are many difficulties for the utilization of hormesis in the field of industrial hygiene. Indeed, it is impossible to test the hormesis hypothesis in many commonly employed experimental model systems for end points of public health concern, and the mechanism of low-dose stimulation of hormesis is not clear. Even if hormesis were proven biologically, its assessment is limited due to difficulties of study design, biological markers selection, statistical power considerations, model and end point selection, and risk model approaches.

Respiratory symptoms and cotton dust exposure; results of a 15 year follow up observation

AIMS

To determine chronic effects of long term exposure to cotton dust and endotoxin on incidence of respiratory symptoms and the effect of cessation of exposure.

METHODS

Respiratory health in 429 Chinese cotton textile workers (study group) and 449 silk textile workers (control group) was followed prospectively from 1981 to 1996. Byssinosis, chest tightness, and non-specific respiratory symptoms were assessed by means of identical standardised questionnaires at four time points. Exposures to cotton dust and endotoxin were estimated using area samples collected at each survey. Incidence and persistence of symptoms were examined in relation to cumulative exposure and exposure cessation using generalised estimating equations (GEE).

RESULTS

Among cotton workers, the cumulative incidence of byssinosis and chest tightness was 24% and 23%, respectively, and was significantly more common in smokers than in non-smokers. A high proportion of symptoms was found to be intermittent, rather than persistent. Among silk workers, no typical byssinosis was identified; the incidence of chest tightness was 10%. Chronic bronchitis, cough, and dyspnoea were more common and persistent in the cotton group than in the silk group. Significantly lower odds ratios for symptoms were observed in cotton workers who left the cotton mills; risk was also related to years since last worked. Multivariate analysis indicated a trend for higher cumulative exposure to endotoxin in relation to a higher risk for byssinosis.

CONCLUSION

Chronic exposure to cotton dust is related to both work specific and non-specific respiratory symptoms. Byssinosis is more strongly associated with exposure to endotoxin than to dust. Cessation of exposure may improve the respiratory health of cotton textile workers; the improvement appears to increase with time since last exposure.

Predictors of whole-body vibration levels among urban taxi drivers

To identify a set of important WBV predictors that could be used to develop a statistical instrument for exposure assessment in a large epidemiologic study, a total of 432 WBV measures were taken from a sample of 247 male drivers in Taipei City, Taiwan. In accordance with the ISO 2631-1 (1997) methods, we measured the frequency-weighted vertical acceleration (z-axis) over drivers' seat surface, under conditions representing different types of rides (vacant vs. short vs. long) assigned to random destinations. Mixed effect models were used to analyse the WBV data including repeated measures. For this group of urban taxi drivers regularly exposed to WBV of low intensity (mean = 0.31 ms( - 2), ranging from 0.17 to 0.55 ms( - 2) r.m.s.), our analyses indicated that average driving speed was the primary predictor (p < 0.0001). As average driving speed increased, measured vertical acceleration increased in a quadratic-linear manner (p < 0.0001). Other WBV predictors, after adjusting for the effects of other covariates, included automobile manufacturer (p = 0.02), engine size (p = 0.04), body weight (p = 0.002), age (p = 0.02), use of seat cushion (p = 0.03), and traffic period (p = 0.02). Our study suggests that a similar statistical approach could be employed in future studies to improve the quality and efficiency of WBV exposure assessment in professional drivers.

Gamma-glutamyltransferase and diabetes--a 4 year follow-up study

AIMS/HYPOTHESIS

Gamma-glutamyltransferase (GGT) is located on the external surface of most cells and mediates the uptake of gluthathione, an important component of intracellular antioxidant defenses. An increase in GGT concentration has been regarded as a marker of alcohol consumption or liver disease. However, more subtle gradations in GGT could be informative because its expression is enhanced by oxidative stress and it could be released by several conditions inducing cellular stress. Recently, serum GGT concentrations have been associated with many cardiovascular disease risk factors or components of the insulin resistance syndrome. We did a prospective study with the hypothesis that serum GGT is a predictor of incident diabetes.

METHODS

A total of 4,088 healthy men working in a steel manufacturing company were examined in 1994 and 1998. Diabetes was defined as a serum fasting glucose concentration of more than 126 mg/dl or the use of diabetes medication.

RESULTS

There was a strong dose-response relation between serum GGT concentrations at baseline and the incidence of diabetes. In contrast to the 31% of men with GGT concentrations under 9 U/l, adjusted relative risks for incidence of diabetes for GGT concentrations 10-19, 20-29, 30-39, 40-49, and over 50 U/l were 8.0, 13.3, 12.6, 19.6 and 25.8, respectively. The associations of age and BMI with incident diabetes became stronger the higher the value of baseline serum GGT concentration.

CONCLUSION/INTERPRETATION

This study suggests that an increase in GGT concentration within its physiological range is a sensitive and early biomarker for the development of diabetes.

A longitudinal observation of early pulmonary responses to cotton dust

AIMS

To examine early adverse pulmonary effects of exposure to cotton dust, and to identify potential risk factors, including atopy for pulmonary responses to cotton dust.

METHODS

Spirometry, methacholine challenge testing, and questionnaire; performed among 101 non-smoking newly hired textile workers at baseline (prior to starting work), and at 3, 12, and 18 months after starting work. Concentrations of airborne cotton dust in various work areas were measured at each follow up survey using vertical elutriators.

RESULTS

The incidence of non-specific respiratory symptoms was 8% at three months, then diminished afterwards. Substantial acute cross shift drops in FEV(1) at each follow up survey, and longitudinal declines in FVC and FEV(1) after 12 months of exposure were observed. Airway responsiveness to methacholine increased with follow up time, and was more pronounced among atopics. Increasing airway responsiveness was strongly correlated with cross shift drops in FEV(1). In addition, one or more respiratory symptoms at three months was significantly, and pre-existing atopy marginally significantly, associated with cross shift drops in FEV(1) after adjusting for other covariates and confounders.

CONCLUSION

Results suggest that non-specific respiratory symptoms, decreasing lung function, and increasing airway responsiveness are early pulmonary responses to cotton dust. In addition, the occurrence of respiratory symptoms and increasing airway responsiveness, as well as atopy, may be important predictors for acute changes in lung function among cotton textile workers.

Reliability of serial urine HCG as a biomarker to detect early pregnancy loss

BACKGROUND

To examine the reliability of HCG as a biomarker for early pregnancy loss, five experienced researchers independently assessed data from 153 menstrual cycles, determining whether each cycle represented 'no conception,' a 'continuing conception' or a 'conception lost.'

METHODS

Urine samples were analysed by immunoradiometric assay using a combination of capture antibodies for the intact heterodimer (B109) and for an epitope common to the beta subunit and the beta core fragment (B204). For each cycle, HCG data were presented as graphs of daily assay results. Summary statistics for HCG assays from 46 women who had undergone bilateral tubal ligation represented baseline values.

RESULTS

Pairwise agreement among the assessors for any of the three options ranged from 78-89%. At least three experts agreed for 147 cycles (96%), accounting for 28 conception losses and 19 continuing conceptions. The multi-rater kappa was 0.62 for the conception lost category and 0.68 for continuing conceptions, indicating substantial agreement.

CONCLUSION

The main sources of disagreement involved deciding whether there was sufficient information for assessment, interpreting cycle parameters such as cycle length or bleeding event, and interpreting a distinct HCG rise pattern that does not exceed the baseline value obtained from the sterilized women.

Differential association of the codon 72 p53 and GSTM1 polymorphisms on histological subtype of non-small cell lung carcinoma

Traditionally, non-small cell lung cancer (NSCLC) has been evaluated as a unique entity in genotyping studies. However, recent biological data suggest that different NSCLC subtypes, specifically adenocarcinomas (AC) and squamous cell carcinomas (SCC), differentially alter cancer behavior. Several studies have associated a p53 polymorphism at codon 72 with NSCLC susceptibility. This study investigated whether different p53 genotypes altered the overall risk of developing AC versus SCC. Polymorphisms in metabolizing enzymes, together with prolonged exposure to tobacco carcinogens, can result in accumulation of DNA damage; these effects may potentiate the effects of subtle differences in p53 function. Thus, interactions between polymorphisms of p53 and either GSTM1 or GSTT1 were also evaluated. We analyzed 1168 incident lung cancer cases and 1256 control subjects using multiple logistic regression. Histological data were available for 1144 cases (98%): 585 with AC, 284 with SCC, and 275 with other histological subtypes (large cell, small cell, mixed, and other). An increase in the NSCLC risk posed by the p53 Pro allele (versus Arg/Arg) was seen in AC compared with controls [adjusted odds ratio (OR), 1.36; 95% confidence interval (CI), 1.1-1.7] but not in SCC (adjusted OR, 1.04; 95% CI, 0.8-1.4). Among AC and SCC cancer patients, individuals with the GSTM1-null genotype had an OR of 1.80 (95% CI, 1.1-2.8; case-only analysis) of having AC versus SCC if they also carried a p53 Pro allele. We conclude that different genotype combinations of p53 and GSTM1 increase the risk of developing specific histological subtypes of NSCLC.

Spirometric surveillance in hazardous materials firefighters: does hazardous materials duty affect lung function?

We analyzed spirometry results for 351 male hazardous materials firefighters from 1996 to 1999 who underwent one or more annual medical surveillance/fitness for duty examinations: 276 (79%) technicians and 75 (21%) support members. Support members had a very limited potential for hazardous materials exposure and served as referents. In cross-sectional comparisons, the technicians' average forced vital capacity and forced expiratory volume in 1 second were either statistically better or not significantly different from that of the support members at all four examinations. Longitudinally, no statistically significant differences were seen for forced vital capacity. The mean percent of predicted forced expiratory volume in 1 second decreased by 3% for technicians (P = 0.029), support controls (P = 0.433), and the total cohort (P = 0.014). Although respiratory irritants are the most common type of exposure in hazardous materials releases, the results suggest that hazardous materials technicians do not lose pulmonary function at a more accelerated rate than support team firefighters.

Is air pollution a risk factor for low birth weight in Seoul?

Environmental factors contributing to reduced birth weight are of great concern because of the well-known relation of birth weight to infant mortality and adverse effects in later life. We examined the associations between air pollution exposures during pregnancy and low birth weight among all full-term births (gestational age 37-44 weeks) for a 2-year period (January 1996 through December 1997) in Seoul, South Korea. We evaluated these associations with a generalized additive logistic regression adjusting for gestational age, maternal age, parental educational level, parity, and infant sex. We used smoothing plots with generalized additive models to analyze the exposure-response relation for each air pollutant. The adjusted relative risk of low birth weight was 1.08 [95% confidence interval (CI) = 1.04-1.12] for each interquartile increase for carbon monoxide concentrations during the first trimester of pregnancy. The relative risks were 1.07 (95% CI = 1.03-1.11) for nitrogen dioxide, 1.06 (95% CI = 1.02-1.10) for sulfur dioxide, and 1.04 (95% CI = 1.00-1.08) for total suspended particles also for interquartile increase in exposure. Carbon monoxide, nitrogen dioxide, sulfur dioxide, and total suspended particle concentrations in the first trimester of pregnancy period are risk factors for low birth weight.