2-chlorobuta-1,3-diene

Health surveillance data

Administrative data

Endpoint:

health surveillance data

Type of information:

other: evaluation of clinical patients

Adequacy of study:

supporting study

Study period:

1956 to 1970

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Publication submitted in Problems of Oncology as a peer reviewed evaluation of human lung cancer prevalence in chlororprene exposed workers. The work is translated from Russian and based on work conducted 40-55 years ago, pre-dating many modern/current human trial or epidemiology testing regimen.

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

1972

Materials and methods

Study type:

medical monitoring

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

The morbidity of a cohort of patients with primary lung cancer was followed over a period of 15 years from 1956 to 1970. All data wre obtained from patients attending an oncology clinic in the Russian town of Yerevan. The patients all had long term occupational exposure histories to chloroprene or chloroprene derivatives via employment in chloroprene production, rubber products factories, shoe and fancy leather goods production or other plants/mills where chloroprene exposure was possible. 87 patients with lung cancer were identified. In total 2934 workers and employees were examined. Three control groups were set up - one including workers with prolonged chemical exposure to non-chloroprene type processes (4780 people); one group drawn from workers in non-chemical based industries (6045 people ) and the third group comprising workers based in cultural/ welfare institutions (6220 people).

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

chloroprene

IUPAC Name:

chloroprene

Details on test material:

No details provided in publication

Method

Type of population:

occupational

Ethical approval:

not applicable

Details on study design:

One cohort of long term exposed workers with exposure to chloroprene and presenting to clinic with clinical conditions.
Three control groups:
control of 4780 people with prolonged exposure to various non-chloroprene type chemicals (e.g. gasoline, lacquers, acetone, benzene acids), the occupations were drivers, polishers, furniture makers, stokers, gasoline storage workers, warehousemen, house painters inter alia.
control group 2 - 6045 people from non-chemical industries e.g. electrical repairmen, carpenters, cabinet makers, electric welders, tin smiths, stove makers.
control group 3 - 6220 people employed in cultural/welfare institutions unrelated to the chemical industry - occupations included school teachers, physician, book-keeper, judges, retired military signalmen, punch operators, washers shift foremen, machine operators, janitors
The rate of development of lung cancer was evaluated in each group, comparisons drawn between control groups and the chloroprene exposed group and mitigating environmental factors considered where possible

Other factors or parameters assessed in the study design included occupational itinerary, age upon starting work, lengh of service, working conditions, pulmonary diseases suffered before and after starting work and any harmful habits (e.g. smoking)

Results and discussion

Any other information on results incl. tables

Of the 2934 workers/employees (over the age of 25) examined in the chloroprene exposure group, 34 were found to be sick or 1.24%. The average age of these individuals was 44.5 years and average length of service was 8.7 years. 18 cases of primary lung cancer were identified in the prolonged chloroprene exposure group - machine operators, cleaners, shift foremen, packers, weighers, pressers and 17 patients in this group with primary lung cancer were involved in exposure to chloroprene latexes - through shoemaking, cutters, gluers, finishers, chemists, shop attendants etc.

In control group I, (prolonged exposure to non-chloroprene type chemicals), 4780 people were examined and 22 cases of primary lung cancer identified (0.46%). The average age of the affected individuals was 54.4 years and average length of service was 10.3 years.

In control group II, (workers in non-chemical industries) 11 individuals (0.8%) were identified with primary lung cancer in a group of 6045 employees. The average age of the affected people was 59.3 years and length od service was 14.9 years. The affected people had occupations including electrical repairmen, carpenters, cabinet makers, electric welders, tin smiths, stove makers etc.

In control group III (employees in cultural/welfare occupations), among people over the age of 25 only 4 cases of disease and 16 individiuals with primary lung cancer were identified (0.064%) in a cohort of 6220 employees. The average age of these four individuals was 60.2 years and the average length of service in their employment was 18.5 years. The occupations of the affected people included a teacher, judge, military signalman, physician and book-keeper. All 16 patients had perforation of the nasal septum.

Of the 87 patients attending the clinic with primary lung cancer 66 (75.8%) suffered from chronic bronchitis, 3 (3.4%) developed tuberculosis after beginning work, 1 (1.1%) had bronchial asthma and 4 (4.5%) had focal pneumonia.

Of the 87 patients 57 (65.5%) were long term or heavy smokers. 87% of the patients developed chronic bronchitis or other respiratory diseases (asthma, pneumonia or tuberculosis).

The rate of development for primary lung cancer was 2.67 fold lower in control group I than in the chloroprene exposed group; 6.3 fold lower in the second control group and 17.5 times lower in the third control group.

Applicant's summary and conclusion

Conclusions:

In a cohort of chloroprene exposed workers, the incidence of lung cancer is apparently increased when compared with worker groups drawn from other occupations or non-chloroprene exposed situations. The controls for smoking and respiratory disease are not in place and details of any workplace controls on exposure are not provided. It is therefore unclear whether the apparent effects observed can be attributed to chloroprene exposure or whether their derivation is from other occupational or social exposures.