Incidence of lymphohaematopoietic malignancies in a petrochemical industry cohort: 1983-94 follow up.

OBJECTIVES: In response to a previous finding of increased mortality from lymphohaematopoietic (LH) malignancies, this study examines incidence of LH malignancy in a petrochemical industry cohort. Emphasis is on chronic lymphocytic leukaemia (CLL) and on comparisons by period of first employment. METHOD: The study cohort consists of 8942 employees who were active in the period 1970-92 and alive on 31 December 1982. Record linkage with the Louisiana tumour registry (LTR) provided information on cancer for cases occurring between 1983 and 1994. Standardised incidence ratios (SIR), with the south Louisiana population as a comparison, were computed for all cancers, all LH malignancies and specific LH subtypes. Analyses were conducted for sex and race categories, and by period of first employment, job type, duration of employment, and latency. RESULTS: 672 Cases of cancer were identified, including 59 LH malignancies. Women (n=1169) had an overall cancer SIR below unity and four LH malignancies versus 2.28 expected. Among the 7773 men, those first employed before 1950 had no overall cancer excess, a significant 1.4-fold increase in overall LH malignancies (43 observed versus 30.78 expected), and four CLL cases versus 3.27 expected. Findings for men first employed after 1950 are based on fewer cases, but there was no indication of excesses of overall cancer or LH malignancy. Numbers were too small in the group first employed after 1950 for meaningful analysis of LH malignancy subtypes such as CLL (one case). CONCLUSION: These findings do not suggest a continuing excess of CLL but do suggest a small increase in incidence of overall LH malignancy for workers first employed before 1950. This may reflect associations with earlier workplace conditions, although work related patterns are mixed. Interpretation is limited by the diverse group of diseases within LH malignancies, and the lack of control for non-work factors other than sex, age, race, and period of diagnosis. This study has a major advantage of more complete and reliable cancer ascertainment compared with the mortality investigation, and shows the feasibility and benefits of using cancer registry incidence data in an occupational cohort study.

Impact of the long term supply of iodized salt to the endemic goitre area.

The study was designed to assess the impact of the supplementation levels of iodine in salt supplied since the last 12 years to Gilgit and Hunza, an endemic goitre area of Pakistan. The overall prevalence of visible goitre is reduced from 61.36% to 4.68%. Results of urinary excretion of iodine (UEI) indicate severe to mild iodine deficiency among 70.41% of the randomly surveyed households. Severely deficient are 3%, moderate 29.54% and mild 37.87%, criteria of UEI being less than 2.0 micrograms/dl, 2-5 micrograms/dl and 5-10 micrograms/dl respectively. Levels of iodine supplementation in 267 iodized salt samples at production (n = 128) and consumption (n = 139) points are compared with a mean +/- SD are 70.86 +/- 29.73 ppm and 37.24 +/- 20.47 ppm respectively, representing 566.8 +/- 237.8 micrograms and 297.9 +/- 163.7 micrograms of iodine per 8.0 gram of salt. It is suggested to replace common salt with iodized salt in the goitre area to ensure the use by all households and quality control measures for iodination of salt should strictly be adhered so that uniform and consistent supply of iodine be ensured. The magnitude of contributory factors other than iodine deficiency, i.e., environmental and hereditary should be monitored and considered when levels of iodine supplementation are adjusted.

Occupational injuries and perception of hazards among road-side welding workers.

A cross-sectional survey was conducted to understand the extent of occupational injuries and the perception of hazards among the road-side welders in the city of Karachi. Burns and foreign body in eyes were reported to be the most common injuries. Few workers perceived their occupation as hazardous. Consequently, few of them reported using protective measures. A 3-step strategy was recommended to improve occupational safety for this and other related groups of workers.