Research on early warning model of the hearing loss of workers exposed to noise / 中华劳动卫生职业病杂志

Objective: To explore the change of hearing threshold of workers exposed to noise, establish an individual-based hearing loss early warning model, accurately and differentiated the health of workers exposed to noise. Methods: In September 2019, all physical examination data of 561 workers exposed to noise from an enterprise were collected since their employment. Three indicators of average hearing threshold of the better ear, namely, at high frequency, 4000 Hz and speech frequency, were constructed. The generalized estimating equation (GEE) was used to adjust gender and age and establish the warning model of each indicator. Finally, sensitive indicators and warning models were screened according to AUC and Yoden index. Results: Among the 561 workers exposed to noise, 26 (4.6%) workers had hearing loss. The sensitivity indicators were the average hearing threshold at speech frequency ≥20 dB, high frequency ≥30 dB and 4000 Hz ≥25 dB. The AUC of each index was 0.602, 0.794 and 0.804, and the Youden indexes were 0.204, 0.588 and 0.608, respectively. In GEE of hearing loss warning models, high-frequency hearing threshold ≥20 dB and 4000 Hz hearing threshold ≥25 dB were the optimal models, with AUC of 0.862. Conclusion: Combined with the changes of individual hearing threshold over the years, can accurately assess the risk of individual hearing loss of workers exposed to noise.

The dose-response relationship of chrysotile asbestos exposure and lung cancer in cohort study / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To clarify the dose-response relationship between asbestos dust exposure and lung cancer incidence in chrysotile asbestos miners by fixed cohort study and to investigate the incidence rates of lung cancer in exposure to different concentrations of asbestos dust.</p><p><b>METHODS</b>A retrospective cohort study was conducted in 1932 asbestos miners who registered from January 1, 1981 to December 31, 1988, had worked for at least 1 year, and had no obvious cardiopulmonary diseases; the cohort study began in July 2009 and covered a time span of 29 years (1981 - 2009). The personal information, occupational history, disease history, and health data of these miners were recorded, and the monitoring data on dust concentrations in the mine over the years were collected. The dose-response relationship between asbestos dust concentration and lung cancer incidence was established by the method of life table; a regression equation was fitted to predict the excess incidence rates of lung cancer under the conditions of different working years and dust concentrations.</p><p><b>RESULTS</b>A significant dose-response relationship was observed between cumulative exposure (Ce) and cumulative probability (Px) of lung cancer incidence, and the smokers hada higher Px than nonsmokers. When Ce was less than 2000 mg/m(3)·each year, Px reached 6.58/10000; when Ce was not less than 2000 mg/m(3)·and less than 3000 mg/m(3)·each year, Px reached 91.72/10000; when Ce was more than 5000 mg/m(3)·each year, Px was as high as 141.02/10000. The three models were fitted to obtain the optimal regression equation: Px = -0.0004Ce(2) + 0.0052Ce - 0.0011 (r(2) = 0.9387). In the workshop of asbestos mine in this study, the average dust concentration was 85 times higher than the limit in 2009, so the excess incidence rate of lung cancer was 112.598/10000 if the miners worked under this condition for 40 years, according to the equation.</p><p><b>CONCLUSION</b>There is a significant dose-response relationship between cumulative asbestos exposure and lung cancer incidence in chrysotile asbestos miners. The risk for lung cancer rises as asbestos exposure increases.</p>

Characteristics and stability of surveillance data on respiratory syndrome, during the Shanghai World Expo in Pudong New District / 中华流行病学杂志

Objective To reveal the characteristics and stability of the system through the analyzing the surveillance data of respiratory-feverous syndrome via the syndromic surveillance system which was established during the Shanghai World Expo in Pudong New District and provide references for the development and operation optimization on this Mass Gatherings Surveillance Systems.Methods Data used was from the surveillance data of respiratory-feverous syndrome collected from Pudong New District Syndromic Surveillance System,through May 1 to October 31,2010.On the basis of description of data characteristics,correlation analyses were conducted,when compared to the surveillance data of respiratory-feverous syndrome and Pudong influenza-like illness (ILI) used as reference.Comparison of variances on the surveillance data and the report lag time of the earlier and later surveillance periods were also carried out to evaluate the quality and stability of data.Results Reports on the respiratory-feverous syndrome showed a peak in late September with day-of-week effects and holiday effects.Correlation between respiratory-feverous syndrome and ILI was the strongest in the same day (r=0.596,P＜0.05).In the earlier surveillance period from 2010-05-01 to 2010-07-31,the correlation between respiratory-feverous syndrome and ILI was not obvious (r=-0.058,P＞0.05) ; however,the two-time series showed consistent trend with the correlation coefficient as 0.798 (P＜0.05),in the later period from 2010-08-01 to 2010-10-31.In addition,variability of the surveillance data on respiratory-feverous syndrome was less in the later period than in the earlier one,with quality of the report on relatcd data better in the later period.Analyses on the correlations of reference sequence,variability and quality of report indicated that the stability of the later surveillance period was better than the earlier one.Conclusion Only with the operation of syndromic surveillance system for a certain period of time,could data in the system maintain stability.Surveillance data showed both day-of-week effects and holiday effects,suggesting that there was a need to choose early warning models with short baseline data.

Effect of magnitude and duration on the performance of Cumulative Sum / 中华流行病学杂志

To explore the effect of magnitude and duration on the performance of Cumulative Sum (CUSUM),with simulation method used on the subject after the insertion of 11 outbreak events into baseline data with Poisson distribution.Sensitivity fluctuated from 9.1％ to 100.0％ with specificities higher than 98.6％.Sensitivity was significantly correlated with magnitude,and increased along with the increase of magnitude.However,no significant correlation was observed between sensitivity and duration.A magnitude which was at least 2.6 times higher than that of the mean daily baseline could result in the sensitivity of 100.0％.Time-lag would be improved along with the increase of magnitude.Time between onset and detection of an outbreak was no longer than one day when magnitude was more than 1.8 of the mean daily baseline.In summary,the performance of CUSUM was influenced by magnitude,but not by duration.CUSUM had the advantage of good time-lag and high sensitivity when the outbreak magnitude was more than 2.4 time over the baseline data.

Nested case-control study of chrysotile and lung cancer / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the relationship between simple exposure to chrysotile and lung cancer.</p><p><b>METHODS</b>The nested case-control study method was used. All of lung cancer cases collected from a male fixed prospective cohort with follow-up of 30 years served as cases and a 1:4 matched proportion was used to select non-cancer case as controls. Controls matched for sex age (+/-5 years old), work time (+/-5 years) and smoking were collected in the same cohort.</p><p><b>RESULTS</b>Forty cases died of lung cancer in the study cohort, and the incidence was higher than the average incidence (SMR =1.77). The top four work types of death density were raw material (741.5), combing and spinning (424.3), weaving (365.0), and repairing (285.5), which was consistent with exposed level. According to the exposed level of chrysotile, the research objects were divided into the high level group and the low level group. The result demonstrated that lung cancer incidence of the high exposed level group of chrysotile was higher (OR = 3.7 95% CI 2.30 approximately 8.16), compared with the low exposed level group.</p><p><b>CONCLUSION</b>Simple exposure to chrysotile can increase the risk of lung cancer for workers who are exposed to chrysotile.</p>