Premature separation of centromere and aneuploidy: an indicator of high risk in unaffected individuals from familial breast cancer families?

OBJECTIVES: Injury is the leading cause of death in the male working population of Brazil. An important fraction of these deaths are work related. Very few cohort studies of steel workers, and none from developing countries, have reported on mortality from injuries. This paper analyses mortality from work and non-work related injuries among Brazilian steel workers. METHODS: Deaths during employment from 1 January 1977 to 30 November 1992 were analysed in a cohort of 21,816 male steel workers. Mortality rates specific for age and calendar year among the workers were compared with those of the male population of the state where the plant is located. Work related injuries were analysed by comparing the mortality rates for different subgroups of the cohort. RESULTS: The number of deaths (391) was less than half that expected based on death rates of the general population. Over 60% (242) of deaths were due to injuries. Mortality from most causes was substantially below that in the general population, but that from unintentional injury, was 50% above that of the general population. Standardised mortality ratios (SMRs) were highest for the youngest and the oldest employees and for labourers and clerical workers. Mortality from motor vehicle injury was twice that expected from population rates (SMR = 209, 95% confidence interval (95% CI) 176-244). There was a 67% fall in the age adjusted mortality from occupational injuries in the study period. CONCLUSION: The healthy worker effect in this cohort was greater than that commonly found in studies of occupational groups in developed countries, probably because of a greater socioeconomic gap between employed and unemployed populations in Brazil, and unequal distribution of health care resources. Mortality was especially high for motor vehicle injuries. The fall in mortality from occupational injuries during the study period was probably due to improvement in safety standards, increased automation, and better medical care. There is a need to investigate risk factors for unintentional injuries among steel workers, especially those due to motor vehicle injuries. Prevention of occupational and nonoccupational injuries should be a main priority in Brazil.     

Lung cancer mortality in a French cohort of hard-metal workers

A cohort mortality study was carried out among workers of a plant producing hard metals using cobalt as a binder. This study was aimed at assessing possible lung cancer risks in relation with cobalt exposure. Seven hundred nine male workers with at least 1 year of employment were included in the cohort and followed for mortality from 1956 to 1989. Job histories were provided by the administration of the plant, whereas smoking habits were collected from medical records and by interview. The causes of deaths were ascertained from hospital and general practitioner records. The observed numbers of deaths (obs) were compared with the expected based on national rates with adjustment for age, sex, and calendar time (standardized mortality ratio; SMR). The overall mortality did not differ from that expected (obs = 75, SMR = 1.05), whereas mortality due to lung cancer was in significant excess (obs = 10, SMR = 2.13). This excess was higher among workers employed in the areas with the highest exposure (obs = 6, SMR = 5.03). No trend was observed, however, with duration of employment or time since first employment. Smoking data were available for 81% of the workers and 69% of the deceased and showed that smoking alone does not account for these lung cancer excesses, yet, because of the small numbers involved, no firm conclusion should be drawn from this study.     

Exposure to styrene and mortality from nervous system diseases and mental disorders

Chronic low-dose exposure to solvents has been associated in epidemiologic studies with chronic neurotoxicity, but the evidence is not consistent. Styrene causes acute disturbances in the central and peripheral nervous systems. To determine if exposure to styrene may contribute to chronic diseases of the central nervous system, the authors examined mortality from nervous system diseases, mental disorders, and suicide in relation to styrene exposure in an international historical cohort study. The cohort involved 35,443 workers employed during 1945-1991 in the reinforced plastics industry, where high exposures to styrene occur. Indicators of exposure were reconstructed through job histories and environmental and biologic monitoring data. Poisson regression was used for internal comparisons. Mortality from diseases of the central nervous system (27 deaths) increased with time since first exposure, duration of exposure, average level of exposure, and cumulative exposure to styrene. A quadratic model described best the dose-response shape for cumulative exposure and duration of exposure with the highest risks at around 300 ppm-years and 5 years, respectively, and a subsequent decrease in risk in the highest exposure categories. Mortality from epilepsy increased monotonically with all styrene exposure indicators, while associations for degenerative diseases of the central nervous system were generally weaker. Mortality from mental disorders and suicide decreased with increasing duration of exposure and cumulative exposure, while there was no trend with time since first exposure and average exposure to styrene. These findings suggest that, in addition to the known acute effects, exposure to styrene may contribute to chronic diseases of the central nervous system.     

Occupational low back pain: history and physical examination

The mortality experience of 7,119 workers who were employed at a Beaumont, Texas, refinery for at least 1 year between 1945 and 1987 was investigated. Mortality analyses based on standardized mortality ratios (SMRs) and 95% confidence intervals (95% CI) showed overall mortality was significantly lower than expected compared with the U.S. general population (SMR = 82, 95% CI = 79-86). Total cancer mortality was also lower than expected (SMR = 92, 95% CI = 84-100). Significant mortality deficits from several malignant and nonmalignant diseases were reported. A significant mortality increase in the broad category of lymphatic and hematopoietic cancers was found (SMR = 133, 95% CI = 103-170). This increase was attributed to a nonsignificant elevation in leukemia of all cell types combined (SMR = 139, 95% CI = 92-201) and a borderline significant increase in other lymphatic tissue cancer (SMR = 158, 95% CI = 101-235). The elevation in leukemia was confined to workers hired before 1950. Furthermore, the leukemia excess was shown to have peaked during the 1960s, with mortality no longer elevated post-1980. Analyses of cell type-specific leukemias showed a similar temporal pattern for acute myeloid leukemia (AML) which was not significantly elevated (SMR = 136, 95% CI = 59-268). Mortality from other leukemia cell types was similar to or lower than expected. Mortality from non-Hodgkin's lymphoma (NHL) (SMR = 140, 95% CI = 88-211) and multiple myeloma (MM) (SMR = 121, 95% CI = 55-230) were increased, but neither was statistically significant nor likely to be related to refinery employment. No death from asbestosis was reported, and mortality from mesothelioma and pulmonary fibrosis was lower than expected. Lung cancer mortality for the overall cohort was similar to expected. For the overall cohort, analyses by duration of employment and time since first employment showed no evidence of any trends for increasing cause-specific mortality. Separate analyses of male workers employed in operator jobs showed mortality patterns that were more favorable than those of the total cohort. Maintenance craftworkers showed statistically significant elevations in mortality for prostate cancer (SMR = 145, 95% CI = 107-194), leukemia (SMR = 179, 95% CI = 111-273), and other lymphatic tissue cancer (SMR = 233, 95% CI = 138-368). Detailed analyses indicated that, among maintenance craftworkers, mortality was elevated for AML, NHL, and MM, but none was significant. Furthermore, no upward trend by duration of maintenance jobs was observed. A small increase of lung cancer was observed among maintenance craftworkers (SMR = 120, 95% CI = 99-145), which was borderline significant. No relationship between lung cancer and duration of maintenance employment was found. In contrast, a deficit of pulmonary fibrosis was reported among maintenance craftworkers (SMR = 62, 95% CI = 17-159). These findings are discussed in conjunction with results from other refinery studies, and the limitations of the study are discussed.     

Stronger occipital cortical activation to lower than upper visual field stimuli. Neuromagnetic recordings

This article present the results of the extension of the follow-up of a cohort of workers employed in an Italian oil refinery. 1,583 workers employed in 1949-1982 in a northern Italy oil refinery plant were followed-up for mortality as of May 31, 1991. Environmental measurements documented potential exposure to benzene. Standardized mortality ratios (SMR) and their 95% confidence intervals (95% CI) were calculated using as references national (1949-1968) and regional mortality rates (1969-1991). Elevated mortality from lymphoma (seven deaths, SMR 190, 95% CI 76-391) and leukemia (eight deaths, SMR 225, 95% CI 97-443) was observed. No consistent trends by length of employment or time since first exposure were apparent. Nonetheless, the excess risk was particularly and significantly increased among workers with 15 or more years of employment, and 30 or more years since first employment. The findings of elevated mortality from leukemia and lymphoma are in agreement with those of other oil refinery studies. Chance, confounding, or other biases might have played a marginal, if any, role in determining the results. Exposure to benzene is a biologically plausible explanation.     

Using alternative comparison populations to assess occupation-related mortality risk. Results for the high nickel alloys workers cohort

The focus of this article is to examine how the choice of comparison group affects the identification and interpretation of cause-specific health risks in occupational cohorts when different external control populations are used. The mortality experience of approximately 31,000 high nickel alloys workers is compared with the total US population and to local populations in geographic proximity to the plants. Generally, the patterns of relative risks derived for the total cohort and various subgroups are similar across the different comparison populations. Estimated elevated risks are usually lower when cohort mortality is compared with that of local populations. An overall significant 13% risk for lung cancer is noted when compared with that of the total US population. However, no significant excess is identified when local populations are used. Subset analysis identified significant excesses of colon cancer among nonwhite males (50%-150%) and kidney cancer among white male workers employed in melting (approximately 100%), irrespective of the comparison population.     

Renal biopsy diagnosis in children presenting with haematuria

OBJECTIVES: This study considers the cause-specific mortality from cancer among art glass workers employed in 17 industrial facilities in Tuscany, Italy. METHODS: A cohort of 3390 workers, 3180 men and 210 women, employed at least 1 year, was taken from company payrolls. It was followed between the year each factory started operation, mostly the mid-1950s, and 31 December 1993. The cause-specific expected mortality from cancer was computed for men relative to Tuscany rates, specified for gender, 5-year age groups, and calendar year. Separate analyses were carried out for the job title of maker and former and for batch mixers. RESULTS: For 3180 men, the observed mortality was above the expected for larynx [standardized mortality ratio (SMR) 166, 90% confidence interval (90% CI) 90-282], lung (SMR 123, 90% CI 100-151), stomach (SMR 105, 90% CI76-142), and brain (SMR 150, 90%CI 71-282) cancer. Increases for these causes were also found for the makers and formers. Mortality from larynx and lung cancer increased with latency, and significantly increased SMR values were observed for > or =21 years since first exposure. The increasing pattern was also present after adjustment for smoking. CONCLUSIONS: The results showed consistently increased mortality from larynx and lung cancer in the overall cohort and among makers and formers. Stomach and brain cancer was also increased in the overall cohort and among the makers and formers.     

An evaluation of digital subtraction radiography for assessment of changes in position of the mandibular condyle

OBJECTIVES: This study evaluated the mortality experience of workers from the styrene-butadiene rubber industry. Concerns about a possible association of 1,3-butadiene and styrene with lymphohaematopoietic, gastrointestinal, and lung cancers prompted the investigation. METHODS: A retrospective follow up study was conducted of 15,649 men employed for at least one year at any of eight North American styrene-butadiene rubber plants. Analyses used standardised mortality ratios (SMRs) to compare styrene-butadiene rubber workers' cause specific mortalities (1943-91) with those of the United States and Ontario general populations. RESULTS: On average, there were 25 years of follow up per subject. The standardised mortality ratio (SMR) was 87 (95% confidence interval (95% CI) 85 to 90) for all causes of death combined and was 93 (95% CI 87 to 99) for all cancers. There was an excess of leukaemia (SMR 131, 95% CI 97 to 174), restricted to hourly workers (SMR 143, 95% CI 104 to 191). For causes of death other than leukaemia, SMRs were close to or below the null value of 100. Results by work area (process group) were unremarkable for non-Hodgkin's lymphoma, multiple myeloma, and stomach cancer. Maintenance workers had a slight increase in deaths from lung cancer, and certain subgroups of workers had more than expected deaths from cancer of the large intestine and the larynx. CONCLUSION: This study found an excess of leukaemia that is likely to be due to exposure to butadiene or to butadiene plus other chemicals. Deaths from non-Hodgkin's lymphoma, multiple myeloma, and stomach cancer did not seem to be related to occupational exposure. The excess deaths from lung cancer among maintenance workers may be due in part to confounding by smoking, which was not controlled for, and in part to an unidentified occupational exposure other than butadiene or styrene. Increases in cancer of the large intestine and larynx were based on small numbers, did not seem to be due to exposure to butadiene or styrene, and may be chance observations.     

Stress and HIV disease progression: psychoneuroimmunological framework

BACKGROUND AND METHODS: A retrospective cohort study was conducted to estimate the effects of low-level exposure to external (penetrating) radiation on cancer mortality among 4,563 workers monitored for external radiation between 1950 and 1993 at a nuclear research and production facility in Southern California. RESULTS: Of the 875 deaths that occurred before 1995, 258 were due to cancer as the underlying cause. External comparisons of male subjects with the U.S. white male population indicated that the workers had lower rates of dying from all causes and all cancers, but a higher rate of dying from leukemia. Internal comparisons of workers exposed at different dose levels, using risk-set analyses with adjustment for confounders, demonstrated an increased mortality rate in workers exposed to 200 mSv for hemato- and lymphopoietic cancers and for lung cancer. Mortality rates for total cancers and "radiosensitive" solid cancers increased monotonically with cumulative radiation dose, but no trends were observed for "nonradiosensitive" cancers. CONCLUSIONS: Despite possible residual confounding and low precision for estimating effects on specific cancers, these findings indicate that chronic, low-level radiation exposure may have more generalized carcinogenic effects than have been observed in most previous investigations. Such effects may have become evident as a result of the relatively long follow-up period in the present study.     

Health effects of artificial mineral fibers

Data from mortality studies in cohorts of workers employed in the production of man-made mineral fibres, where levels of exposure were generally low, show an excess of mortality by lung cancer, although the role of the fibres themselves remains unclear in this excess. Standardized mortality ratio for lung cancer was lower in glass-wool production workers than in rock-slag-wool workers. Preliminary data for refractory ceramic fibres-exposed workers suggest the occurrence of benign pleural diseases and obstructive functional defects. Attention should be paid to levels of exposure to various man-made mineral fibres encountered by end-users commonly exposed to peaks of fibre concentrations higher than production workers.     

Risk of death from malignant neoplasms among paper mill workers

A cohort study was designed to evaluate the risk of death from malignant neoplasms among pulp and paper workers. This paper presents the evaluation of death risk among workers engaged only in the production of paper, paperboard and paper products. The cohort study covered 1,322 males and 1,914 females employed for, at least, one year in a big pulp and paper mill during the period 1968-90. The study of exposure to harmful factors revealed that concentrations of paper and paperboard dusts in this mill exceeded hygienic standards. The analysis of death risk by causes and gender of those under study was based on standardized mortality rate (SMR) calculated using the method of person-year observation. The general population of Poland was used as reference. The results do not confirm excess mortality from lung, stomach and hematopoietic cancers in paper mill workers reported by other authors. However, an elevated risk of bladder cancer in males (SMR = 491, two deaths) and brain cancer in females (SMR = 353, two deaths) was observed. Both SMR values were not statistically significant. Because of small number of deaths, risk according to exposure and latency was not evaluated.     

HIV-1 disease progression and AIDS-defining disorders in rural Uganda

BACKGROUND: The majority of people infected with HIV-1 live in Africa, yet little is known about the natural history of the disease in that continent. We studied survival times, disease progression, and AIDS-defining disorders, according to the proposed WHO staging system, in a population-based, rural cohort in Uganda. METHODS: In 1990 we recruited a random sample of people already infected with HIV-1 (as prevalent cases) detected during the initial survey round of a general-population study to form a natural-history cohort. Individuals from the general-population cohort who seroconverted between 1990 and 1995 (incident cases) were also invited to enroll. Participants were seen routinely every 3 months and when they were III. FINDINGS: By the end of 1995, 93 prevalent cases and 86 incident cases had been enrolled. Four patients in the prevalent group were in stage 4 (AIDS) at the initial visit. During the next 5 years, 37 prevalent cases progressed to AIDS. Seven incident cases progressed to AIDS and the cumulative progression to AIDS at 1, 3, and 5 years after seroconversion was 2%, 6%, and 22%, respectively. The cumulative probability of AIDS at 4 years from entering stages 1, 2, and 3 was 11%, 33%, and 58%, respectively. There were 47 deaths among prevalent cases and seven among incident cases during follow-up. The cumulative mortality 4 years after patients entered stages 1, 2, 3, and 4 was 9%, 33%, 56%, and 86%, respectively. The median survival after the onset of AIDS was 9.3 months. INTERPRETATION: Our results are important for the setting of priorities and rationalisation of treatment availability in countries with poor resources. We found that progression rates to AIDS are similar to those in developed countries for homosexual cohorts and greater than for cohorts infected by other modes of transmission. However, we have found that the rates of all-cause mortality are much higher and the progression times to death are shorter than in developed countries.     

Unit risk estimates for airborne arsenic exposure: an updated view based on recent data from two copper smelter cohorts

The current unit risk for airborne arsenic, 4.29 x 10(-3), was established by the EPA in 1984. Using updated results from a cohort mortality study on Tacoma smelter workers and recent findings from a cohort study of 3619 Swedish smelter workers, new unit risk estimates were developed for the respective cohorts. Methods were analogous to those used by the EPA in 1984, and all estimates were derived under an absolute risk model. A new unit risk 1.28 x 10(-3), was estimated for the Tacoma smelter cohort which was a factor of 5 less than the EPA's earlier estimate, and a direct result of radically revised exposure estimates. A unit risk of 0.89 x 10(-3) was estimated from the Swedish study. Pooling these new unit risk estimates with the EPA's earlier estimates from the Montana smelter cohort yielded a composite unit risk of 1.43 x 10(-3). Based on this estimate, the present unit risk may overestimate the effects of airborne arsenic by a factor of 3. A need to update the unit risk for airborne arsenic and the collateral IRIS database is evident from the results.     

The effect of system restructuring on absenteeism due to sickness in the work place. I. Sickness absenteeism during the period 19989-1994

The current transformation of property relations and economic restructuring, along with many other factors, influence the health condition of workers. The objective of the study was to illustrate the size of the problem and to identify the major causes of work disability among persons employed in enterprises undergoing those processes during the years 1989-94 against the situation observed in the whole country during the same period. The study was carried out in one of the largest industrial plants undergoing the process of economic restructuring. The group investigated was composed of 8,588 workers (including 62.6% of males). In individual years the number of workers in this group was decreasing, and in 1994 the employment status in the group accounted for 37% in relation to the number of workers employed during the first year under observation. The analysis of work disability was based on the rate of sickness absenteeism calculated as a relationship between the number of days of work disability and the number of working days during that particular period. Due to the application of this method it was feasible to consider both workers employed and persons who left the plant, regardless of their employment duration during a year. The study showed a 20 per cent increase in sickness absenteeism during the period of 1989-94. The highest rate (8.60) was noted in 1994. It was higher by 16% in comparison to the rate for the whole country. The greatest difference between these rates was observed in 1990 (the rate in the group investigated was higher by 46%). As to the causes of work disability, the main differences concerned two categories of illnesses, diseases of the circulatory system, a major cause of sickness absenteeism in the group studied (21%), and diseases of the musculoskeletal system, a major cause of sickness absenteeism in Poland. The change in the relationship between sickness absenteeism and the age during the period of the plant restructuring resulted from the fact that a large number of workers left the job. It was observed that the rate of the sickness absenteeism was almost directly proportional to the percentage of persons leaving the plant in individual years. The study showed that changes in the size and the structure of employment resulting from the plant restructuring influence the level of sickness absenteeism, and the age-related diversification in causes of diseases, and in consequence alter the established regularities.     

The impact of unemployment on health: a review of the evidence

OBJECTIVE: To review the scientific evidence supporting an association between unemployment and adverse health outcomes and to assess the evidence on the basis of the epidemiologic criteria for causation. DATA SOURCES: MEDLINE was searched for all relevant articles with the use of the MeSH terms "unemployment," "employment," "job loss," "economy" and a range of mortality and morbidity outcomes. A secondary search was conducted for references from the primary search articles, review articles or published commentaries. Data and definitions of unemployment were drawn from Statistics Canada publications. STUDY SELECTION: Selection focused on articles published in the 1980s and 1990s. English-language reports of aggregate-level research (involving an entire population), such as time-series analyses, and studies of individual subjects, such as cross-sectional, case-control or cohort studies, were reviewed. In total, the authors reviewed 46 articles that described original studies. DATA EXTRACTION: Information was sought on the association (if any) between unemployment and health outcomes such as mortality rates, specific causes of death, incidence of physical and mental disorders and the use of health care services. Information was extracted on the nature of the association (positive or negative), measures of association (relative risk, odds ratio or standardized mortality ratio), and the direction of causation (whether unemployment caused ill health or vice versa). DATA SYNTHESIS: Most aggregate-level studies reported a positive association between national unemployment rates and rates of overall mortality and mortality due to cardiovascular disease and suicide. However, the relation between unemployment rates and motor-vehicle fatality rates may be inverse. Large, census-based cohort studies showed higher rates of overall mortality, death due to cardiovascular disease and suicide among unemployed men and women than among either employed people or the general population. Workers laid off because of factory closure have reported more symptoms and illnesses than employed people; some of these reports have been validated objectively. Unemployed people may be more likely than employed people to visit physicians, take medications or be admitted to general hospitals. A possible association between unemployment and rates of admission to psychiatric hospitals is complicated by other institutional and environmental factors. CONCLUSIONS: Evaluated on an epidemiologic basis, the evidence suggests a strong, positive association between unemployment and many adverse health outcomes. Whether unemployment causes these adverse outcomes is less straightforward, however, because there are likely many mediating and confounding factors, which may be social, economic or clinical. Many authors have suggested mechanisms of causation, but further research is needed to test these hypotheses.     

A defensive role of IgE mediated reaction in the nose

Using the accumulated data on deaths from mesothelial tumours among cohorts of male and female factory workers at a London asbestos textile factory, the mortality from this cause up to the year 2000 AD has been predicted. The limitations of the methods used are pointed out, but it is estimated that for men the mortality due to mesothelial tumours will be between 7% and 11% of the total mortality and somewhat higher for women. The highest number of deaths from mesothelial tumours will occur during the 1980s, thereafter the numbers will decline because of the decreasing size of the cohort resulting from general mortality.     

Comparative study of the death during sea voyages among Polish seamen and deep-sea and boat fishermen

181 fatal cases of diseases and work-related accidents recorded in the years 1985-1994 among seamen and fishermen were analyzed. The highest mortality rate and fatal accident rate were noted in seamen. They were higher than those pertaining to workers employed on land. The respective rates for Polish fishermen were lower than those reported in other countries. The main causes of death at sea were sea catastrophes, injuries, drowning, poisoning and circulatory system diseases. The most frequent were deaths during the day and not on the watch, being alone in the cabin. Limited access to qualified medical assistance during the voyage and frequent occurrence of sudden deaths reduce substantially the efficacy of help. Therefore, prevention of diseases and accidents is of crucial importance.     

Mortality among a cohort of electric utility workers, 1960-1991

Overall mortality trends among an electric utility workforce are examined. The study cohort (n = 40,335) included all workers with at least 1 year of work experience from 1960-1991; 3,753 deaths were observed in this cohort. Standardized mortality ratios (SMRs) and internal cohort analyses were used to assess mortality trends for the entire cohort and for specific occupational groups. Most SMRs were < or = 1.0 and were generally lower for noncancer (cardiovascular, COPD, and injuries) than for cancer mortality. Compared to office staff, rate ratios (RR) were higher for respiratory cancers for field staff [(RR = 2.3, 95% CI, 1.0-5.0) linecrew (RR = 2.2 95% CI, 1.5-3.1), and power plant occupations (RR = 2.4, 95% CI, 1.6-3.6)]. Nonmanagement occupations had rate ratios for motor vehicle injuries and all types of injuries, within a range of 2.5-4.7, with all lower CIs > 1.0. The healthy worker effect is an important factor in explaining the difference between SMR and internal cohort analyses results. The SMR results indicate that this workforce has lower rates for overall mortality, cardiovascular disease, cancer and nonintentional injury. A consistent finding in the internal cohort analyses that merits further research was higher mortality rates for respiratory cancer and injuries among nonoffice staff.     

Brain cancer in petrochemical workers: a case series report

Eighteen primary brain cancer deaths among male workers at one Texas petrochemical plant from 1965-1980 are reported. Federal officials from OSHA and NIOSH are performing with company cooperation an historical prospective cohort mortality study, a case-control study, and neuropathological case confirmation. Average age at death was 53 (range 30-66). Median employment was 21 years and median latency was 24 years. 15/18 tumors were glioblastoma multiforme, an unusual histologic distribution. A preliminary estimate reveals a plant-wide excess brain cancer risk twice expected among 6,800 white males at the plant since 1941. Brain cancer mortality rates in surrounding counties are in the median range for US counties from 1950-1969. Ten recognized or suspected carcinogens are present in quantities greater than 10(6) lbs/yr. To date no common chemical exposures or work assignments have been identified among the cases. Data on 26 experimental brain carcinogens and relevant epidemiological studies are provided.     

Mass screening for neuroblastoma and mortality in birth cohorts

Mortality resulting from neuroblastoma in birth cohorts in both Sapporo City and the whole of Japan was investigated to evaluate the effects of a high-performance liquid chromatography (HPLC) mass screening program, targeting on 6 month-old infants. In Sapporo City, the non-HPLC screened cohort showed no reduction in mortality at 4 years of age compared with the pre-screening cohort. However, the HPLC screened cohort showed a reduction of 69% in mortality compared with the pre-screening cohort. On a nation-wide scale, there was a significant decline in mortality for the non-HPLC screened cohort compared with the pre-screening cohort; for the HPLC screened cohort for 1989-1991, there was also a reduction in mortality for children younger than 2 years of age. The incidence of neuroblastoma at 1-4 years of age in the HPLC cohort in Sapporo City was about half that in the pre-screening cohort, along with and probably because of an increasing incidence among infants in the same cohort. Our findings suggest that HPLC screening may detect some poor-prognosis neuroblastoma cases at early stages, thus providing for more favorable therapy.