Establishment and application of a prospective follow-up research method for acute infectious diseases in Shanghai community residents / 上海预防医学

ObjectiveTo present the exploration and application of a prospective follow-up research method for acute infectious disease surveillance based on natural community populations， using COVID-19 infection as an example， and to provide a reference for improving the infectious disease surveillance and early warning system. MethodsA multi-stage probability proportional sampling method was employed to sample residents from all communities of 16 administrative districts in Shanghai， with households as the units. A cohort for acute infectious diseases based on natural community populations was established. The baseline survey was conducted for all cohort subjects， and COVID-19 antigen test kits were distributed. From December 21， 2022 to September 30， 2023， prospective follow-up monitoring of COVID-19 antigen and nucleic acid was carried out on the study subjects on a weekly basis. The baseline characteristics and follow-up information of the cohort subjects were described. ResultsThe cohort for acute infectious diseases included a total of 12 881 subjects， comprising 6 098 males （47.3%） and 6 783 females （52.7%）. The baseline survey revealed that 35.2% （4 540/12 881） of the subjects had a history of COVID-19 infection. During the follow-up period from December 21， 2022 to September 30， 2023， the average incidence density in the cohort was 0.61/person-year， with a higher incidence density in females （0.63/person-year） compared to males （0.59/person-year）. Individuals aged 60 and above （0.64/person-year） and those with underlying health conditions （0.67/person-year） had a higher incidence density. Healthcare workers showed a notably higher incidence density （0.84/person-year） than that in other occupational groups. As of September 30， 2023， a total of 340 subjects in the cohort experienced secondary infections， with a median interval of 170 days between the first and second infections. ConclusionThis study applies cohort study method to acute infectious disease surveillance， providing crucial data support for estimating infection rates and forecasting alerts for acute infectious diseases in the community. This method can be promoted and applied as a new approach for acute infectious disease surveillance.

Incidence density and relative rate assessment of knee osteoarthritis with respect to BMI, age and gender conducted in a tertiary care hospital in Hyderabad, India

Background: Osteoarthritis is the most common form of arthritis associated with limitation in mobility. Weight bearing joints of axial and peripheral skeleton are primarily affected. Prevalence of symptomatic knee osteoarthritis among men and women is 10% and 13%. Ageing and obesity epidemic are the leading causes for development of osteoarthritis in a given population. Methods: The study was conducted at a tertiary care hospital in Hyderabad, India. Data was gathered from orthopedic department on a daily basis during the study duration. Patients with any grade of Kellgren-Lawrence scale of knee osteoarthritis were included in the study and incidence density, relative rate, p-value were assessed. Results: During the study course, a total of 100 patients were enrolled. Overweight, obese and healthy patients contributed to 51%, 33% and 16% of incidence density with relative rate as 1.04, 0.49 and 0.19 respectively (p-value=0.042). Incidence density of patients ?45 years and <45 years was 83% and 17% with relative rate as 4.9 and 0.2 (p value<0.0001). Incidence density in males and females was 34% and 66% with relative rate as 1.94 and 0.51 (p-value<0.0001). The data analyzed is statistically significant. Conclusions: A direct proportionality between people exceeding normal BMI range and progression of knee osteoarthritis is observed due to strain manifested on diarthrodial joint by overweight patients. Increase in age is associated with onset of knee osteoarthritis because of age related-changes seen in cartilage and loss of chondrocytes. Women are more affected with knee osteoarthritis when compared to men due to irregularities in hormones post-menopause.

Incidence of cutaneous carcinoma, herpes zoster and cataracts in patients with psoriasis vulgaris receiving narrow-band ultraviolet B phototherapy: a single-center retrospective study / 中华皮肤科杂志

Objective:To investigate the effect of narrow-band ultraviolet B (NB-UVB) phototherapy on the incidence of cutaneous carcinoma, herpes zoster and cataracts in patients with psoriasis vulgaris.Methods:A telephone follow-up was conducted among patients with psoriasis vulgaris receiving NB-UVB phototherapy at the Department of Dermatology, Peking Union Medical College Hospital from January 1, 2003 to December 31, 2019. The incidence of cutaneous carcinoma, herpes zoster and cataracts was investigated, and their incidence density and 95% confidence intervals ( CIs) were calculated. Subgroup analyses were performed according to the cumulative number of NB-UVB radiation (≤ 100 times, 101 - 300 times, > 300 times), cumulative radiation energy (≤ 100 J/cm 2, > 100 - 500 J/cm 2, > 500 J/cm 2), and average radiation frequency (≤ 1.5 times/week, > 1.5 times/week). Univariate Cox′s proportional hazards regression analysis was conducted to analyze differences in the incidence density of cutaneous carcinoma, herpes zoster, and cataracts between the groups, and the results were expressed as hazard ratios ( HRs) and their corresponding 95% CIs. Results:A total of 160 patients with psoriasis vulgaris completed the follow-up, including 99 males (61.9%) and 61 females (38.1%). Their ages (median [ Q1, Q3]) were 39 (28.3, 54.8) years, the cumulative numbers of NB-UVB radiation were 129.5 (52, 291) times, the cumulative radiation energy was 226.3 (71.1, 688.9) J/cm 2, and the average radiation frequencies were 1.57 (1.37, 1.83) times/week. No cutaneous carcinoma occurred during the follow-up of 1 288.87 person-years (7.77 [5.11, 9.92] years) ; herpes zoster occurred in 4 cases during the follow-up of 1 273.85 person-years (7.68 [5.11, 9.88] years), and the estimated incidence density of herpes zoster was 31.4/10 000 person-years (95% CI: [11.8 - 83.5]/10 000 person-years) ; cataracts occurred in 8 cases during the follow-up of 1 264.67 person-years (7.72 [4.84, 9.83] years), and the estimated incidence density of cataracts was 63.3/10 000 person-years (95% CI: [31.7 - 126.2]/10 000 person-years). No significant differences were observed in the incidence density of herpes zoster or cataracts among subgroups with different cumulative numbers of NB-UVB radiation, cumulative radiation energy and average radiation frequencies (all P > 0.05) . Conclusion:The incidence of herpes zoster or cataracts may not be affected by the cumulative number of NB-UVB radiation, cumulative radiation energy or average radiation frequency in patients with psoriasis vulgaris.

Epidemiological study on the incidence of inflammatory bowel disease in Yinzhou District, Ningbo City from 2011 to 2020 / 北京大学学报(医学版)

OBJECTIVE@#To describe the distribution characteristics of inflammatory bowel disease among permanent residents in Yinzhou District, Ningbo City, and to understand the disease burden and development trend of inflammatory bowel disease in this area.@*METHODS@#Using the retrospective cohort design, we collected the registration information of all permanent residents in the residents' health files of the Yinzhou Regional Health Information Platform from 2010 to 2020, and used electronic medical records to follow up their inflammatory bowel disease visits. A one-year wash-out period was set, and the patients who were diagnosed with the primary diagnosis for the first time after one year of registration were re-garded as new cases. The incidence density and 95% confidence interval (CI) of inflammatory bowel disease were estimated by Poisson distribution.@*RESULTS@#From 2011 to 2020, a total of 1 496 427 permanent residents in Yinzhou District were included, of which 729 996 were male (48.78%). The total follow-up person-years were 8 081 030.82, and the median follow-up person-years were 5.41 [interquartile range (IQR): 5.29]. During the study period, there were 1 217 new cases of inflammatory bowel disease, of which males (624 cases, 51.27%) were more than females (593 cases, 48.73%). The total incidence density was 15.06/100 000 person-years (95%CI: 14.23, 15.93). Among all new cases, there were 1 106 cases (90.88%) of ulcerative colitis, with an incidence density of 13.69 per 100 000 person-years (95%CI: 12.89, 14.52); 70 cases (5.75%) of Crohn's disease, with an incidence density of 0.87 per 100 000 person-years (95%CI: 0.68, 1.09); and 41 cases (3.37%) of indeterminate colitis, with an incidence density of 0.51 per 100 000 person-years (95%CI: 0.36, 0.69). The median age of onset of ulcerative colitis was 50.82 years old (IQR: 18.77), with the highest proportion (15.01%) in the 45-49 years group. The incidence density of ulcerative colitis gradually increased with age, reaching a relatively high level in the 45-49 years group (20.53/100 000 person-years; 95%CI: 17.63, 23.78), followed by a slight increase. And the incidence density in the 65-69 years group was the highest (25.44/100 000 person-years; 95%CI: 20.85, 30.75), with a rapid decrease in the 75-79 years group. The median age of onset of Crohn's disease was 44.34 years (IQR: 33.41), with the highest proportion (12.86%) in the 25-29 years group. Due to the small number of new cases of Crohn's disease, the age distribution fluctuated greatly, with peaks both in young and old people. From 2011 to 2020, the incidence density of inflammatory bowel disease in Yinzhou District was at a low level from 2011 to 2013, and showed a rapid upward trend from 2014 to 2016, reaching a peak of 24.62 per 100 000 person-years in 2016 (95%CI: 21.31, 28.30), and slightly decreased in 2017-2020.@*CONCLUSION@#The incidence density of inflammatory bowel disease in Yinzhou District from 2011 to 2020 was at a relatively high level, and medical institutions and health departments need to pay attention to the burden of disease caused by it.

How to use χ2 test correctly——the independence test for the data of the person-time / 四川精神卫生

The purpose of this paper was to introduce the independence test and the SAS implementation for the "unstratified person-time data" and the "stratified person-time data". In "person-time data"， the sample size in each level of the treatment factor was expressed as "person-years". Furthermore， it was necessary to use the "incidence density" to replace the "incidence rate" in the usual qualitative data analysis. The paper introduced the concrete approaches of comparing the "incidence density" of the "unstratified person-time data" and the "stratified person-time data" in detail， and demonstrated the whole process of using SAS software to realize the calculation through two examples， including the SAS program code， the SAS output results， the results explanation and the conclusion statement.

Epidemiological study of infantile epilepsy incidence density among infants under 36 months of age in Ningbo City from 2015 to 2019 / 北京大学学报(医学版)

OBJECTIVE@#To describe the distribution and trend of infantile epilepsy among infants under 36 months in Ningbo, Zhejiang Province.@*METHODS@#Using the birth cohort design, we retrospectively collected the local born infants in Ningbo national health information platform from 2015 to 2019, and took the first visit of epilepsy in the electronic medical record of the platform as the new case. The incidence density and 95% confidence interval (CI) of epilepsy were estimated by Poisson distribution.@*RESULTS@#From 2015 to 2019, a total of 294 900 children were born in Ningbo, with male accounting for 51.92%. The total person-years of observation were 595 300, while the median follow-up person-years was 2.31 [interquartile range (IQR): 1.90]. There were 575 new onset epilepsy patients during the whole observation period. The total number of visits was 2 599, with an average of 4.52. The total incidence density was 96.59/100 000 person-years (95%CI: 88.85-104.82). The median age of onset was 13 months (IQR: 15), 0-12 months old infants had the highest incidence density (102.18/100 000 person-years), 25-36 months old infants had the lowest incidence density (89.68/100 000 person-years), and the difference was not statistically significant (P>0.05). The incidence density of male was 97.58/100 000 person-years, female was 95.53/100 000 person-years, and the difference was not statistically significant (P>0.05). Fenghua was the highest (130.54/100 000 person-years, 95%CI: 94.47-175.83) and Ninghai was the lowest (66.44/100 000 person-years, 95%CI: 47.02-91. 19), with significant difference (P < 0.05). There was no significant difference in the incidence density in different birth years (P>0.05). There was significant difference in the incidence density between 0-12 months old infants in different calendar years (Ptrend < 0.05). In this age group, the incidence density was the lowest in 2015 (69.41/100 000 person-years, 95%CI: 41.79-108.39), and the highest in 2019 (225.61/100 000 person-years, 95%CI: 186.10-271.03). There was no significant difference in the incidence density between 13-24 and 25-36 months old infants in different calendar years (P>0.05).@*CONCLUSION@#The incidence density of epilepsy in 0-36 months old infants in Ningbo City from 2015 to 2019 was low as a whole, and there was no difference in age group, gender, and year of birth. The incidence density of 0-12 months old infants increased with the year.

Estudo epidemiológico e caracterização de coorte de pacientes com infecção por Clostridioides difficile internados no Hospital das Clínicas da UFMG / Epidemiological study and characterization of a cohort of patients with Clostridioides difficile infection hospitalized at the Hospital das Clínicas of UFMG

Introdução: a infecção por Clostridioides difficile (ICD) é a principal causa bacteriana de diarreia infecciosa associada aos cuidados de saúde e é responsável por significativa morbimortalidade, assim como por custos elevados relacionados ao tratamento em todo o mundo. Na Europa e nos Estados Unidos a densidade de incidência varia entre 2,9 e 8,3 casos/10.000 pacientes-dia. Não existem dados precisos sobre a taxa de incidência na América Latina. Objetivos: obter a medida da densidade de incidência da ICD associada aos cuidados de saúde em hospital de alta complexidade e descrever o perfil desta coorte de pacientes. Métodos: foi realizada busca ativa diária de casos de diarreia durante o período de 3 meses, entre abril e julho de 2021. Os casos suspeitos foram submetidos ao teste rápido para pesquisa da glutamato desidrogenase (GDH) e das toxinas A e B de C. difficile. Nas amostras positivas apenas para o GDH, a confirmação diagnóstica foi feita por meio da cultura toxigênica. Resultados: foram identificados 104 pacientes com diarreia e o C. difficile toxigênico foi responsável por 21 casos. A densidade de incidência foi de 9,2 casos para cada 10.000 pacientes-dia. A mediana de idade dos pacientes com ICD foi de 63 (19-80) anos, 57,1% eram do sexo masculino e a média do Índice de Comorbidades de Charlson foi de 4,10 (±2,49). Dezessete pacientes (81%) fizeram uso de antibiótico (ATB) nos 3 meses que precederam a infecção e a média do número de ATB foi de 3,29 (±2,72). A ICD foi considerada grave em 11 pacientes (52,4%). Vancomicina foi opção inicial de tratamento em 14 pacientes (66,7%), e 11 pacientes (52,4%) apresentaram resposta até o quinto dia. Dois pacientes estavam no segundo episódio de ICD e um paciente apresentou recorrência após período de recrutamento. Ocorreram três óbitos, provavelmente não relacionados à ICD. Conclusão: a medida da densidade de incidência foi alta e aponta para a necessidade de medidas que visem melhor controle da infecção. A amostra de pacientes foi caracterizada como complexa, com múltiplas comorbidades, uso recente de vários ATB e mortalidade alta.

Introduction: Clostridioides difficile (ICD) infection is the leading bacterial cause of healthcare-associated infectious diarrhea and it is responsible for significant morbidity and mortality rates, as well as treatment-related costs worldwide. In Europe and the United States, the incidence density varies between 2.9 and 8.3 cases/10,000 patient-days. There is no precise data about the incidence rate in Latin America. Objectives: get the measure of the incidence density of healthcare-related ICD in a high-complexity hospital and to define the profile of this cohort of patients. Methods: daily active search for diarrhea cases was carried out during a 3-month period, between April and July 2021. Suspected cases were submitted to a rapid test for glutamate dehydrogenase (GDH) and C. difficile toxins A and B. In samples positive only for GDH, diagnostic confirmation was made through toxigenic culture. Results: 104 patients with diarrhea were identified and toxigenic C. difficile was responsible for 21 cases. The incidence density was 9.2 cases for every 10,000 patient-days. The median age of patients with ICD was 63 (19-80) years, 57.1% were male and the mean Charlson Comorbidity Index was 4.10 (±2.49). Seventeen patients (81%) used antibiotics (ATB) in the 3 months preceding the infection and the mean number of ATB was 3.29 (±2.72). ICD was considered severe in 11 patients (52.4%). Vancomycin was the initial treatment option in 14 patients (66.7%) and 11 patients (52,4%) responded by the fifth day. Two patients were in the second episode of ICD and one patient had recurrence after the recruitment period. There were three deaths, probably unrelated to CDI. Conclusion: The measure of incidence density was high and points to the need for measures aimed at better infection control. The sample of patients was characterized as complex, with multiple comorbidities, recent use of multiple ATB and high mortality.

A large scale cohort study on the immunization effect of hepatitis B vaccine in Fujian province / 中华流行病学杂志

Objective: To evaluate the effectiveness of hepatitis B vaccination in Fujian province. Methods: Based on the hepatitis B immunization strategy of China, a cohort study was designed, involving the population in Fujian province. The population under study was divided into natural exposure birth cohort before 1992 and the immunization birth cohort after 1992 (including voluntary vaccination cohort and standardized vaccination cohort). By cleaning the database of hepatitis B cases which directly reported through network and looked into the incidence and related death outcomes of acute hepatitis B from 2004 to 2017, the incidence levels of hepatitis B and immunization effects were analyzed and evaluated among different birth cohorts. Results: During the observation period, the overall prevalence of hepatitis B in Fujian province was 44.594 per 100 000, with mortality rate as 0.010 per 100 000. The incidence of natural exposure cohort of birth was 56.885 per 100 000. The incidence of voluntary vaccination cohort of birth was 14.502 per 100 000. Compared with the voluntary vaccination cohort, the risk of hepatitis B increased significantly in the natural exposed cohort (RR=3.923), and the difference was statistically significant (P=0.000 7), with attributable risk as 42.383 per 100 000. The attributable risk ratio was 74.507. The population attributable risk ratio was 70.967%. The population attributable risk was 35.448 per 100 000. The attributable rate in standardized vaccination cohorts born after 2002 was 2.336 per 100 000. Compared with the cohorts born before 1992, the RR was 24.347 (P=0.000 0), the attributable risk was 54.549 per 100 000, and the attributable risk ratio was 95.893%, the population attributable risk ratio was 95.300%, the population attributable risk was 47.371 per 100 000, comparing to the natural exposed population. Conclusions: The effectiveness of hepatitis B immunization program had been remarkable in Fujian province since 1992. However, further studies on the persistency of hepatitis B vaccine immunization and its public health significance still needed to be carried out.

A large scale cohort study on the immunization effect of hepatitis B vaccine in Fujian province / 中华流行病学杂志

Objective To evaluate the effectiveness of hepatitis B vaccination in Fujian province.Methods Based on the hepatitis B immunization strategy of China,a cohort study was designed,involving the population in Fujian province.The population under study was divided into natural exposure birth cohort before 1992 and the immunization birth cohort after 1992 (including voluntary vaccination cohort and standardized vaccination cohort).By cleaning the database of hepatitis B cases which directly reported through network and looked into the incidence and related death outcomes of acute hepatitis B from 2004 to 2017,the incidence levels of hepatitis B and immunization effects were analyzed and evaluated among different birth cohorts.Results During the observation period,the overall prevalence of hepatitis B in Fujian province was 44.594 per 100 000,with mortality rate as 0.010 per 100 000.The incidence of natural exposure cohort of birth was 56.885 per 100 000.The incidence of voluntary vaccination cohort of birth was 14.502 per 100 000.Compared with the voluntary vaccination cohort,the risk of hepatitis B increased significantly in the natural exposed cohort (RR=3.923),and the difference was statistically significant (P=0.000 7),with attributable risk as 42.383 per 100 000.The attributable risk ratio was 74.507.The population attributable risk ratio was 70.967％.The population attributable risk was 35.448 per 100 000.The attributable rate in standardized vaccination cohorts born after 2002 was 2.336 per 100 000.Compared with the cohorts bom before 1992,the RR was 24.347 (P=0.000 0),the attributable risk was 54.549 per 100 000,and the attributable risk ratio was 95.893％,the population attributable risk ratio was 95.300％,the population attributable risk was 47.371 per 100 000,comparing to the natural exposed population.Conclusions The effectiveness of hepatitis B immunization program had been remarkable in Fujian province since 1992.However,further studies on the persistency of hepatitis B vaccine immunization and its public health significance still needed to be carried out.

Prevalência e incidência de infecção pelo vírus da dengue em uma comunidade urbana: Um estudo de coorte / Prevalence and incidence of infection by the dengue virus in an urban community: A cohort study

A dengue é uma doença febril aguda transmitida pela picada do mosquito Aedes aegypti. Em torno de 40% da população mundial vive em áreas tropicais e subtropicais sob risco de infecção e desenvolvimento da doença. No Brasil, a dengue é uma doença de grande impacto para a saúde pública. Entretanto, poucos estudos de coorte prospectiva foram realizados para estimar a incidência de infecções e para identificar grupos populacionais de maior risco para infecção. Identificar grupos de risco pode ajudar a orientar os programas de prevenção e controle da dengue, de modo a reduzir a carga da doença. Este estudo teve como objetivos determinar a soroprevalência e a densidade de incidência e fatores demográficos e socioeconômicos associados à infecção pelo vírus da dengue em uma comunidade urbana. Um estudo de coorte foi realizado nas comunidades de São Marcos e Pau da Lima, bairros periféricos de Salvador-BA que apresentam infra-estrutura sanitária deficiente. Foram incluídos 2.323 participantes com idade ≥5 anos, residentes em domicílios selecionados aleatoriamente na comunidade. A coorte foi recrutada entre janeiro e junho de 2010 e o seguimento se deu após um ano, entre janeiro e maio de 2011...

Dengue fever is an acute febrile disease transmitted by the mosquito Aedes aegypti. Around 40% of the world population lives in tropical and subtropical areas at risk of infection and disease development. In Brazil, dengue is a disease of great impact on public health. However, few prospective cohort studies have been conducted to estimate the incidence of infections and to identify population groups at higher risk for infection. The identification of risk groups can help guide prevention programs and dengue control in order to reduce the burden of disease. This study aimed to determine the prevalence and incidence density and socioeconomic and demographic factors associated with dengue virus infection in an urban community. A cohort study was conducted in the communities of San Marcos and Pau da Lima, outskirts of Salvador-BA who have poor health infrastructure. About 2,323 participants aged ≥ 5 years, residents in households randomly selected in the community were included. The cohort was recruited between January and June 2010 and follow-up occurred after one year, between January and May 2011...

Incidence Density and Risk Factors of Low Back Pain among the Workers in a Welding Material Manufacturing Factory / 한국역학회지

This study was performed to understand the incidence density and detect the risk factors of occupational low back pain. A cross-sectional study was conducted with a questionnaire in a welding material manufacturing factory in October, 1993. Therefore, we selected 140 workers who had never complained of low back pain as cohorts. Also, we added 236 newly entered persons who had never complained of low back pain. The total number of cohorts were 376 workers. And then we continued with a questionnaire survey in October, 1996 and with a questionnaire survey and medical examinations by a specialist in October, 1997. Follow-ups were done for 337 workers. The number of newly developed low back pain among workers were 127. The characteristics of low back pain were as follows. The durations of pain were less than or equal to 2 days (42.6%), from 3 days to less than 1 week (8.7%), from 1 week to less than 1 month (11.0%), 1 month or more (6.2%). The frequency was everyday (7.9%), once per week (21.3%), once per month (14.2%), once per 2-3 months (9.4%), once per 5 months (11.0%). The severity of pain was slight (9.4%), mild (33.1%), moderate (13.4%), severe (10.2%) and very severe (1.6%). The onset of most low back pain was insidious (41.7%). The diagnosis of low back pain was muscle strain (37.8%), lumbar sprain (23.6%) and myofacial pain syndrome (3.9%). The number of newly developed low back pain among workers were 127, their incidence density was 15.7 per 100 person-years. In univariate analysis, age, marital status, educational level, smoking habit, category of job, tenures and frequency of stretching exercises showed a statistical significance. The multivariate logistic regression analysis confirmed that category of job and tenures (p<0.05) were independent risk factors for low back pain among workers. The number of newly developed occupational low back pain among production workers were 71, their incidence density was 11.3 per 100 person-years. In univariate analysis, age, marital status, educational level, regular exercise, tenures, posture of waist and lifting of heavy materials showed a statistical significance. The multivariate logistic regression analysis confirmed that posture of waist (p<0.05) and lifting of heavy materials (p<0.1) were independent risk factors for occupational low back pain among production workers.

Development of Coalworkers' Pneumoconiosis in Korea: Risk Factors and Incidence Density / 대한산업의학회지

Pneumoconiosis, especially Coal-workers' Pneumoconi6sis(GWP), is the principal occupation-related disease in Korea because of the large number of affected workers. Coal mines and miners have been reduced abruptly during recent 8 years, but coal mining should be kept in Korea. Recently, pneumoconiotic workers are increasing in manufacturing industry. It is necessary to know the characteristics of CWP to prevent the development of CWP and manage employed or retired pneumoconiotic workers. Furthermore, it is also necessary to study CWP to protect workers from pneumoconiosis in manufacturing industry. Of the total of 6,452 workers who were diagnosed as CWP initially during the 20 years from 1973 to 1992, X-ray category was as follows: category 1(35.2%), category 2(23.1%), suspicious (0/1 category, 13.4%), category 3(5.7%), large opacity (3.5%), unknown by. complete classification (19.1%). The patients' cardiopulmonary disability was as follows: no disability 79.3%, slight 14.2%, mild 4.1%, moderate 1.9%, severe 0.5%. The patients' X-ray category and disability were not related with the initially exposed age or job position, but their severity was positively related with the exposed duration that was adjusted by the initially exposed age. Also, the patients' X-ray category and disability had positive relationship each other. The cumulative exposure dose of silica/was more important than that'of respirable dust in the. development of large opacity CWP. The annual incidence density of CWP was 73.2 persons in 1982 and 75.8 persons in 1986per 10,000 person years. Afterthen it has been gradually decreasing and was in the range of 20-30 persons in the period of 1989-1992.