Corrigendum: Evaluation of N95 respirators on fit rate, real-time leakage, and usability among Chinese healthcare workers: study protocol of a randomized crossover trial.

[This corrects the article DOI: 10.3389/fpubh.2023.1266607.].

Evaluation of N95 respirators on fit rate, real-time leakage, and usability among Chinese healthcare workers: study protocol of a randomized crossover trial.

Background: N95 respirators are used to limit the transmission of respiratory viruses in clinical settings. There are two to three major types of N95 available for all healthcare workers in Hong Kong. However, after the coronavirus outbreak and the consequent shortage of many commonly used respirators, several new N95 respirators were adopted temporarily in clinical settings without evaluation. Prior literature indicates that traditional N95 respirators used in hospitals in Hong Kong are not fit for Chinese people and have fit rates ranging from 50 to 60%. This study aims to investigate and compare the fit rate, real-time leakage, and mask usability of traditional and new N95 respirators among Chinese healthcare workers. Methods: This study will employ two sequential phases. Phase 1 has a cross-sectional exploratory design used to investigate the fit rate and mask usability of three types of respirators. Phase 2 will examine the effectiveness of respiratory protection by comparing traditional and new N95 respirators by a randomized crossover trial. Eligible participants will be randomly allocated through a controlled crossover experiment to either a traditional or new respirator group (n = 100 in each arm) for performing standard clinical procedures. The primary outcome (real-time leakage) will be recorded at 30 s intervals during nasopharyngeal suctioning and cardiopulmonary resuscitation. The secondary outcomes are the fit rate and mask usability. After a 2 min suctioning (15 s twice) and 4 min one-person CPR, the fit rate (assessed by standard N95 fit testing) and mask usability (measured by self-reported mask usability scale) will be recorded as data of post-procedure. After 10 min rest, measurement of real-time leakage (i.e., crossover), fit test, and usability will be repeated. Discussion: The result of real-time leakage will be a vital indicator of the respiratory protection of Chinese healthcare workers while performing prevalent clinical procedures, such as resuscitation. The fit rate and usability result will serve as an essential reference for consumable purchase policy in clinical settings.Trial registration: ISRCTN registry: ISRCTN40115047. Retrospectively registered on May 9, 2023. https://www.isrctn.com/ISRCTN40115047.

Risk assessment and prediction for lung cancer among Hong Kong Chinese men.

OBJECTIVE: Most of the previous risk prediction models for lung cancer were developed from smokers, with discriminatory power ranging from 0.57 to 0.72. We constructed an individual risk prediction model for lung cancer among the male general population of Hong Kong. METHODS: Epidemiological data of 1,069 histology confirmed male lung cancer cases and 1,208 community controls were included in this analysis. Residential radon exposure was retrospectively reconstructed based on individual lifetime residential information. Multivariable logistic regression with repeated cross-validation method was used to select optimal risk predictors for each prediction model for different smoking strata. Individual absolute risk for lung cancer was estimated by Gail model. Receiver-operator characteristic curves, area under the curve (AUC) and confusion matrix were evaluated to demonstrate the model performance and ability to differentiate cases from non-cases. RESULTS: Smoking and smoking cessation, education, lung disease history, family history of cancer, residential radon exposure, dietary habits, carcinogens exposure, mask use and dust control in workplace were selected as the risk predictors for lung cancer. The AUC of estimated absolute risk for all lung cancers was 0.735 (95% CI: 0.714-0.756). Using 2.83% as the cutoff point of absolute risk, the predictive accuracy, positive predictive value and negative predictive value were 0.715, 0.818 and 0.674, respectively. CONCLUSION: We developed a risk prediction model with moderate discrimination for lung cancer among Hong Kong males. External validation in other populations is warranted for this model in future studies.

Lung cancer risk in painters: results from the SYNERGY pooled case-control study consortium.

OBJECTIVES: We evaluated the risk of lung cancer associated with ever working as a painter, duration of employment and type of painter by histological subtype as well as joint effects with smoking, within the SYNERGY project. METHODS: Data were pooled from 16 participating case-control studies conducted internationally. Detailed individual occupational and smoking histories were available for 19 369 lung cancer cases (684 ever employed as painters) and 23 674 age-matched and sex-matched controls (532 painters). Multivariable unconditional logistic regression models were adjusted for age, sex, centre, cigarette pack-years, time-since-smoking cessation and lifetime work in other jobs that entailed exposure to lung carcinogens. RESULTS: Ever having worked as a painter was associated with an increased risk of lung cancer in men (OR 1.30; 95% CI 1.13 to 1.50). The association was strongest for construction and repair painters and the risk was elevated for all histological subtypes, although more evident for small cell and squamous cell lung cancer than for adenocarcinoma and large cell carcinoma. There was evidence of interaction on the additive scale between smoking and employment as a painter (relative excess risk due to interaction >0). CONCLUSIONS: Our results by type/industry of painter may aid future identification of causative agents or exposure scenarios to develop evidence-based practices for reducing harmful exposures in painters.

Smoking cessation sharply reduced lung cancer mortality in a historical cohort of 3185 Chinese silicotic workers from 1981 to 2014.

BACKGROUND: Population-based studies showed an over 50% decrease in lung cancer risk after quitting smoking for 5-6 years, but the beneficial effect in silicotics remains unknown. We aimed to rectify this knowledge gap using a large historical cohort of 3185 Chinese silicotics since 1981 and followed-up till 2014. METHODS: Baseline information on workers' socio-demographics, smoking habits, occupational history, and medical history was collected. Smoking status was reassessed during follow-up. Multiple Cox proportional hazards model was performed to evaluate the impact of smoking cessation on lung cancer mortality. RESULTS: Overall, 1942 deaths occurred and 188 lung cancer deaths were identified. Compared with never quitters, silicotics who were new quitters had almost halved their lung cancer risk [hazard ratio (HR) = 0.51, 95%CI: 0.34-0.76], while persistent quitters had a 53% risk reduction (HR = 0.47, 95%CI: 0.33-0.66). Lung cancer mortality approximately halved after quitting smoking for 10 years. While the risk kept decreasing with years since cessation, it did not reverse back to that of never smokers. Persistent quitters with small opacities tended to have higher beneficial effects than those with large opacities. CONCLUSIONS: Smoking cessation for 10 years halved lung cancer mortality among silicotics, while the beneficial effect was prominent for patients with small opacities.

Differential incidence trends of colon and rectal cancers in Hong Kong: an age-period-cohort analysis.

BACKGROUND: Colorectal cancer has been the second most common cancer among men and women in Hong Kong since 2012, but the underlying reasons for this increase remain unclear. We describe the incidence trend for colorectal cancer in Hong Kong to explore its etiology within this population. METHODS: The temporal trends in colorectal cancer incidence between 1983 and 2012 were analyzed with joinpoint regressions by sex, age groups, and anatomic sites among adults using data from the Hong Kong Cancer Registry. An age-period-cohort analysis was used to evaluate the effects of age, calendar periods, and birth cohorts on the observed temporal trends. RESULTS: The incidence of colon cancer among those aged 50 years and older in both sexes increased steadily from 1983 until the mid-1990s and was followed by a slight decrease thereafter, whereas the incidence among those aged 20-49 years decreased steadily from 1983 to 2012. In contrast, the incidence of rectal cancer steadily increased in men and remained stable in women throughout the study period. Significant period and birth cohort effects were observed for colon cancer, whereas period effects on the temporal trends were observed for male rectal cancer. CONCLUSIONS: The incidences of colon and rectal cancers have exhibited divergent patterns between 1983 and 2012 in Hong Kong, indicating heterogeneous etiologies between these two types of cancers. Surveillance of the risk factors related to colon and rectal cancers in the Hong Kong population should be performed, and the increased rectal cancer incidence in males is worthy of extra attention.

International employee perspectives on disability management.

PURPOSE: To provide an international analysis of employees' views of the influence of disability management (DM) on the workplace. METHODOLOGY: An international research team with representation from Australia, Canada, China, and Switzerland collected survey data from employees in public and private companies in their respective regions. Due to lack of availability of current measures, a research team-created survey was used and a total of 1201 respondents were collected across the four countries. ANALYSIS: Multiple linear (enter) regression was also employed to predict DM's influence on job satisfaction, physical health, mental health, workplace morale and reduced sickness absence, from respondents' perceptions of whether their company provided disability prevention, stay-at-work, and return-to-work initiatives within their organization. One-way ANOVA comparisons were used to examine differences on demographic variables including company status (public versus private), union status (union versus nonunion), and gender. RESULTS: The perceived influence of DM programs was related to perceptions of job satisfaction; whereas, relationships with mental health, physical health, morale, and sickness absence were variable according to type of DM program and whether the response was related to self or others. Difference analyses (ANOVA) revealed significantly more positive perceptions for private and nonunion organizations; no gender effects were found. CONCLUSIONS: There is perceived value of DM from the perspective of employees, especially with respect to its value for coworkers. Implications for Rehabilitation Rehabilitation efforts should continue to focus attention on the value of disability management (DM). In particular, DM that is fully committed to the biopsychosocial model would be supported by this research. Employees reported the most value in the psychosocial variables addressed by DM, such that rehabilitation professionals could focus on these valued aspects to improve buy-in from employees. The interest in coworker value may provide another avenue for rehabilitation efforts to increase uptake, by highlighting the value of intervention efforts for employee coworkers. Rehabilitation professionals in union environments may need to be particularly cognizant of the need for encouraging psychosocial and coworker value potentially seen by employees in order to increase acceptance and participation for organizational DM efforts.

History of Asbestos Ban in Hong Kong.

As millions of immigrants moved to Hong Kong (HK) from China in the recent decades, large amount of residential housings were built in the early years and a substantial proportion of those buildings used asbestos-containing materials (ACMs). Since the number of new cases of ARDs diagnosed has increased year by year since 1990's, the remarkable increase of incidences had drawn the attention of the public and most importantly the HK government. It became one of the trigger points leading to asbestos ban in HK history. Comparatively, non-governmental organizations (NGOs), labor unions and patients' self-help organizations demonstrated a more aggressive and proactive attitude than the HK government and have played a key role in the development of asbestos banning policy in HK. After numerous petitions and meetings with the government representatives by those parties in the past decade, the HK government eventually changed its attitude and started to consider terminating the endless threat from asbestos by amending the policy, and the new clause of legislation for banning of all forms of asbestos was enacted on 4 April 2014. Other than the restriction of asbestos use, the compensation system about ARDs has also made some great moves by the effort of those parties as well. Based on the experience we learnt through the years, efforts from different stakeholders including patients' self-help organizations, NGOs, legislative councilors, and media power are absolutely essential to the success of progression and development in today's asbestos banning in HK.

Disability management and organizational culture in Australia and Canada.

BACKGROUND: Organizational culture has received increasing attention in terms of its influence on workplace health and productivity, yet there has been little research on its relationship with employer-based disability programs. OBJECTIVE: This study explored the relationship between disability management and organizational culture in Australian and Canadian organizations. METHODS: Thematic analysis was conducted on data from semi-structured interviews with 16 employees, including injured workers, human resource managers and disability managers in two Australian and two Canadian large organizations. RESULTS: Seven themes were identified: 1. Consistency between espoused beliefs and artifacts in organization; 2. Genuineness of interest in well-being of injured worker; 3. Level of ongoing support of worker following injury; 4. Communication with injured workers; 5. Level of support from supervisors and co-workers; 6. Promptness in claims processing and covering medical costs and; 7. Focus on wellness and injury prevention. It was found that organizational culture may impact the delivery and perceived value of employer-based disability management programs. CONCLUSIONS: Given the potential relationship between organizational culture and disability management, employers should facilitate a positive workplace culture by ensuring consistency among underlying values, espoused values and actual treatment of employees, including injured workers.

Disparities of time trends and birth cohort effects on invasive breast cancer incidence in Shanghai and Hong Kong pre- and post-menopausal women.

BACKGROUND: Breast cancer is the leading cause of cancer morbidity among Shanghai and Hong Kong women, which contributes to 20-25% of new female cancer incidents. This study aimed to describe the temporal trend of breast cancer and interpret the potential effects on the observed secular trends. METHODS: Cancer incident data were obtained from the cancer registries. Age-standardized incidence rate was computed by the direct method using the World population of 2000. Average annual percentage change (AAPC) in incidence rate was estimated by the Joinpoint regression. Age, period and cohort effects were assessed by using a log-linear model with Poisson regression. RESULTS: During 1976-2009, an increasing trend of breast cancer incidence was observed, with an AAPC of 1.73 [95% confidence interval (CI): 1.54-1.92)] for women in Hong Kong and 2.83 (95% CI, 2.26-3.40) in Shanghai. Greater upward trends were revealed in Shanghai women aged 50 years old or above (AAPC = 3.09; 95% CI, 1.48-4.73). Using age at 50 years old as cut-point, strong birth cohort effects were shown in both pre- and post-menopausal women, though a more remarkable effect was suggested in Shanghai post-menopausal women. No evidence for a period effect was indicated. CONCLUSIONS: Incidence rate of breast cancer has been more speedy in Shanghai post-menopausal women than that of the Hong Kong women over the past 30 years. Decreased birth rate and increasing environmental exposures (e.g., light-at-night) over successive generations may have constituted major impacts on the birth cohort effects, especially for the post-menopausal breast cancer; further analytic studies are warranted.

Dietary patterns and the risk of rhinitis in primary school children: a prospective cohort study.

This study was to investigate the association between dietary patterns and rhinitis in primary school children. 1,599 students without rhinitis at baseline survey were selected from a primary school children cohort. Information on food consumption, respiratory symptoms, and confounders was collected using questionnaires. Dietary patterns were defined using principal component analysis. Logistic regression was performed to calculate odds ratio (OR) with 95% confidence intervals (95% CI). The incidence of rhinitis during 12 months follow-up was 21.2%. Three patterns were extracted and labeled as pattern I, II and III. Dietary pattern II which had higher factor loadings of legumes, butter, nuts and potatoes was associated with an increased risk of rhinitis (OR: 1.34, 95% CI: 1.01-1.87) when the highest tertile of pattern score was compared to the lowest tertile, after adjusted for confounders. Besides, every 1-unit increase of score of pattern II was also associated with an increased risk of rhinitis (OR: 1.19, 95% CI: 1.05-1.35). Neither pattern I nor Pattern III was observed to be associated with risk of rhinitis. A diet with higher levels of consumption of legumes, butter, nuts and potatoes may increase the risk of allergic rhinitis in primary school children.

Nighttime eating and breast cancer among Chinese women in Hong Kong.

BACKGROUND: A novel line of research suggests that eating at nighttime may have several metabolic consequences that are highly relevant to breast cancer. We investigated the association between nighttime eating habits after 10 p.m. and breast cancer in Hong Kong women. METHODS: A hospital-based case-control study was conducted during 2012-2015. A total of 922 patients with incident breast cancer (cases) and 913 hospital controls were recruited and interviewed using a standard questionnaire including information on eating behavior during both daytime and nighttime. We collected the timing, duration, types and frequencies of food intake of eating at nighttime. Odds ratios (ORs) for the risk of breast cancer in relation to nighttime eating-related variables were calculated by unconditional multivariable logistic regression. RESULTS: Eating at night after 10 pm was significantly associated with breast cancer with an adjusted OR of 1.50 (95% confidence interval (CI) 1.06-2.12, P = 0.02), and the associations were stronger in women who had the longest duration of nighttime eating (≥20 years) (adjusted OR = 2.28 (95% CI 1.13-4.61, P = 0.02) and who ate late (midnight to 2 a.m.) (adjusted OR = 2.73, 95% CI 1.01-6.99, P = 0.04). Interestingly, nighttime eating was only associated with breast cancer among women who consumed staple foods (OR = 2.16, 95% CI 1.42-3.29, P < 0.001) but not those who ate vegetables or fruits as nighttime meals. The significant association between nighttime eating and breast cancer was observed among women with body mass index (BMI) <25 (OR = 2.29, 95% CI 1.48-3.52, P < 0.001) but not among women with BMI ≥25. CONCLUSIONS: Results from this study suggest a possible association between nighttime eating behavior and breast cancer. These findings need to be confirmed by independent large studies.

Occupational risk factors for nasopharyngeal carcinoma in Hong Kong Chinese: a case-referent study.

PURPOSE: This study aimed to investigate the occupational risk factors for nasopharyngeal carcinoma (NPC) in Hong Kong Chinese. METHODS: We conducted a case-referent study with 352 incident cases and 410 referents recruited between June 2010 and December 2012. Full occupational histories were obtained via face-to-face interviews. Unconditional logistic regressions were performed to estimate the odds ratios (ORs) for NPC associated with occupational risk factors. RESULTS: Workers of craft related trades and elementary occupations were at elevated NPC risk with the adjusted ORs of 2.09 [95% confidence interval (CI) 1.09, 4.01] and 2.14 (95% CI 1.04, 4.41), respectively, compared with those clerical support workers as the reference group. Occupational exposures to cotton dust, chemical fumes, and welding fumes were significantly associated with increased NPC risk after adjustment for confounders [adjusted ORs (95% CIs) 1.93 (1.13, 3.28), 13.11 (1.53, 112.17), and 9.18 (1.05, 80.35), respectively]. We also observed significant exposure-response relationship for the duration of exposure to cotton dust (P for trend = 0.0175). Those with occupational exposure to cotton dust for 15 years or more were at significantly increased risk of NPC (adjusted OR 2.08, 95% CI 1.01, 4.28). CONCLUSIONS: This study indicates that employment in craft related trades and elementary occupations, as well as occupational exposures to chemical fumes, welding fumes, and cotton dust may be associated with an increased risk of NPC. Further epidemiological studies remain warranted to clarify the roles of specific occupational risk factors on NPC development.

Prognostic value of alcohol consumption and some other dietary habits for survival in a cohort of Chinese men with lung cancer.

BACKGROUND: Alcohol consumption and some other dietary habits are thought to be associated with lung cancer incidence. However, the effects of these habits on lung cancer prognosis have been studied rarely. The purpose of this study was to address these gaps in knowledge. METHODS: We studied a cohort of 1052 Chinese men in Hong Kong who were diagnosed with primary lung cancer. Cox proportional hazards models were used to determine the prognostic values of consumption of alcohol, fresh fruits or vegetables, meat, and fried or preserved food. RESULTS: Compared with never drinkers, men who drank alcohol 1-3 days per week had a more favorable lung cancer prognosis (hazard ratio [HR]: 0.82, 95% confidence interval [CI] 0.68-0.97); however, this survival advantage was not significant in men who drank alcohol more frequently (HR: 0.91, 95% CI 0.73-1.14). Compared with men who consumed preserved or fried food only occasionally, men who consumed these foods frequently had a higher risk of lung cancer mortality (HR: 1.20, 95% CI 1.00-1.42). CONCLUSIONS: Occasional consumption of alcohol was a favorable survival factor for Chinese men with lung cancer. However, this survival benefit did not exist for frequent drinkers of alcohol. Chinese men with lung cancer who were frequent consumers of fried or preserved food had a worse prognosis than those who consumed these foods only occasionally.

Effectiveness of participatory training in preventing accidental occupational injuries: a randomized-controlled trial in China.

Objective The aim of this study was to evaluate the effectiveness of a participatory training program in preventing accidental occupational injuries in factories in Shenzhen, China. Methods We conducted a cluster randomized study with the worker as the unit of analysis, providing 918 workers from 30 factories participatory training. Two control groups received traditional didactic training, including 907 workers from the same 30 factories and 1654 workers in matched control factories. We used generalized estimating equations to compare the before/after person-based injury rate difference in the three groups and binary logistic regression to compare the re-injury rates. Results The person- and event-based incidence rates of accidental injury in the intervention group reduced from 89.3 to 52.1 per 1000 workers (P=0.002) and from 138.3 to 74.5 per 1000 person-years (P<0.001), respectively. The rate reductions in the two control groups were not statistically significant. Compared with the intervention group, the risk of accidental work injury over time was higher in the control groups, with odds ratios (OR) 1.78 (1.04-3.04) and 1.77 (1.13-2.79) for control_1 and control_2 group, respectively. The re-injury rates were 27.1% (13/48) in the intervention group, and 41.7% (15/36) and 52.6% (51/97) in the two control groups respectively, with the latter being significantly higher than the intervention group. Conclusions Our study documented the effectiveness of a participatory approach to occupational health and safety training in reducing accidental work injuries and re-injuries among frontline workers.

Dietary patterns and the risk of esophageal squamous cell carcinoma: A population-based case-control study in a rural population.

BACKGROUND & AIMS: Few studies were available in exploring the roles of dietary patterns in the development of esophageal cancer, especially in China. This study aimed to investigate the roles of dietary patterns in the risk of esophageal squamous cell carcinoma (ESCC) in a Chinese rural population. METHODS: A population-based cases-control study was designed and conducted in Yanting County, Sichuan Province of China during two years (between June 2011 and May 2013). A total of 942 pairs of ESCC cases and controls were recruited. A food frequency questionnaire was adopted to collect information of dietary consumption. Dietary patterns were extracted by using principle component and factor analysis based on 24 dietary groups. Odds ratios (ORs) with 95% confidence intervals (95% CI) were calculated by using logistic regression model, with adjustment for possible confounding variables. RESULTS: Four major dietary patterns were identified, which were labeled as "prudent", "vegetable and fruits", "processed food" and "alcohol drinking". In comparison of the highest with the lowest quartiles of pattern scores, the processed food pattern (OR: 2.84, 95% CI: 2.13-3.80) and alcohol drinking pattern (OR: 2.69, 95% CI: 1.95-3.71) were significantly associated with an increased risk of ESCC, while the vegetable and fruit pattern (OR: 0.70, 95% CI: 0.53-0.92) was associated with reduced risk by 30%. The prudent pattern was associated with a reduced risk by 33% (OR: 0.67, 95% CI: 0.50-0.88) in a multivariate logistic regression model, but no statistical significance was reached in a composite model. CONCLUSIONS: The results suggest an important role of dietary patterns in ESCC. Diets rich in vegetables and fruits may decrease the risk of ESCC, whereas diets rich in processed food and drinking alcohol may increase the risk.

Lung Cancer Among Firefighters: Smoking-Adjusted Risk Estimates in a Pooled Analysis of Case-Control Studies.

OBJECTIVES: The aim of this study was to explore lung cancer risk among firefighters, with adjustment for smoking. METHODS: We used pooled information from the SYNERGY project including 14 case-control studies conducted in Europe, Canada, New Zealand, and China, with lifetime work histories and smoking habits for 14,748 cases of lung cancer and 17,543 controls. We estimated odds ratios by unconditional logistic regression with adjustment for smoking and having ever been employed in a job known to present an excess risk of lung cancer. RESULTS: There was no increased lung cancer risk overall or by specific cell type among firefighters (n = 190), neither before nor after smoking adjustment. We observed no significant exposure-response relationship in terms of work duration. CONCLUSIONS: We found no evidence of an excess lung cancer risk related to occupational exposure as a firefighter.

Frequent use of household cleaning products is associated with rhinitis in Chinese children.

BACKGROUND: Despite the popular use of household cleaning products worldwide, there is no published study investigating the health effects of these products on rhinitis in children. OBJECTIVE: We sought to investigate the household use of cleaning products and rhinitis patterns in Chinese children. METHODS: A total of 2299 children were recruited from 21 primary schools with wide geographic coverage in Hong Kong. Self-administered questionnaires were completed by parents/guardians to collect detailed information on respiratory symptoms and household use of 14 types of chemical cleaning products, as well as clean water. Students were categorized into 4 mutually exclusive rhinitis patterns (never, occasional, frequent, and persistent). The total chemical burden (TCB) score was used as the exposure indicator by calculating the total time of exposure to the 14 cleaning products. Multinomial logistic regression was used to assess the relationship between rhinitis patterns and the use of household cleaning products. RESULTS: Every 10-unit increment of TCB score was associated with an increase in the odds of occasional (odds ratio [OR], 1.21; 95% CI, 1.05-1.41), frequent (OR, 1.36; 95% CI, 1.13-1.60), and persistent (OR, 1.21; 95% CI, 1.01-1.56) rhinitis after adjustment for a wide range of potential confounders. Compared with the children within the lowest tertile of TCB scores, the adjusted ORs of occasional, frequent, and persistent rhinitis in children within the highest tertile were 1.29 (95% CI, 1.01-1.65), 1.97 (95% CI, 1.40-2.76), and 1.67 (95% CI, 1.10-2.54), respectively. CONCLUSION: Frequent use of chemical cleaning products at home is associated with an increase in the odds of rhinitis in Chinese primary school children.

Secondhand Smoke Enhances Lung Cancer Risk in Male Smokers: An Interaction.

INTRODUCTION: Previous studies revealed that some indoor air pollutants and fine particle matter can interact with active smoking, enhancing lung cancer risk in smokers. Secondhand smoke (SHS), with remarkable differences from active smoking, contributes significantly to indoor air pollution and generates a considerable amount of fine particle matter, may cause a similar interaction with active smoking. METHODS: Information on lifetime SHS along with active smoking and other confirmed or suspected risk factors for lung cancer was collected in this case-referent study. Odds ratios and the 95% confidence intervals (95% CIs) of smoking status in different levels of SHS were evaluated. Potential multiplicative and additive interactions were explored. RESULTS: Compared with never-smokers without SHS, current smokers who were exposed to a high level of SHS demonstrated the highest odds ratio (15.13, 95% CI: 8.60, 26.65), almost doubles the effect in the current smokers without SHS. Significant additive interactions between current smoking and high level of SHS were observed for all lung cancers (synergy index = 1.80, 95% CI: 1.02, 3.24) and the squamous carcinoma subgroup. CONCLUSIONS: High level of SHS exposure greatly enhanced lung cancer risk among current smokers, consistent with an additive interaction; while this interaction was predominant for the squamous carcinoma. The results provide new evidence to the rationale of promoting global smoking cessation. IMPLICATIONS: Some indoor air pollutants can interact with active smoking, yielding a synergistic effect on inducing lung cancer. SHS, with noticeable differences from active smoking, is a major source of indoor air pollution. However, little has been known about the effect of SHS in smokers and whether there is a similar interaction between SHS and active smoking. In this study, we evaluated their separate and joint effects and indeed found a more than additive interaction between them. This finding suggests a potential problem of gathering smoking aggravating by venue restriction policies and re-advocates policy efforts on smoking cessation.

Exposure-response estimate for lung cancer and asbestosis in a predominantly chrysotile-exposed Chinese factory cohort.

BACKGROUND: Cumulative fiber exposures, predominantly chrysotile, were estimated in a Chinese asbestos worker cohort and exposure-response relationships with lung cancer mortality and cumulative incidence of asbestosis were determined. METHODS: Individual time-dependent cumulative exposures were estimated for 577 asbestos workers, followed prospectively for 37 years. Occupational history and smoking data were obtained from company records and personal interviews; vital status and causes of death were ascertained from death registries and hospital records. Hazard ratios were generated for disease outcomes, with adjustments for smoking and age. RESULTS: Median cumulative fiber exposure for the cohort was 132.6 fiber-years/ml (IQR 89.3-548.4). Exposure-response relationships were demonstrated for both disease outcomes, with nearly sixfold and threefold increased risks seen at the highest exposure level for lung cancer deaths and asbestosis, respectively. CONCLUSION: Evidence using quantitative exposure estimates was provided for increased risks of lung cancer mortality and development of asbestosis in a predominantly chrysotile-exposed cohort.