Occupation and lung cancer risk among women in northern China

Lifetime occupational histories were obtained in a case-control study of 965 female lung cancer patients and 959 controls selected from the general population in Shenyang and Harbin, People's Republic of China, where most women have worked outside the home. After adjusting for smoking, we found a significantly increased risk of lung cancer associated with employment involving the manufacture of transportation equipment (OR = 1.6, 95% CI = 1.0, 2.6), in particular the manufacturing of automobiles (OR = 3.0, 95% CI = 1.4, 6.4). Metal smelting and treatment workers were at an increased risk of lung cancer (OR = 1.5, 95% CI = 1.0, 2.1); the highest risks were observed among metal surfacers (OR = 3.1, 95% CI = 1.1, 9.0) and currently employed foundry workers (OR = 13.0, 95% CI = 1.7, 99.4). On the other hand, about a 50% decreased risk of lung cancer was observed among those employed in textile industries or as leaders of state and party organizations. Based on self-reports, exposures to coal dust and smoke from burning fuel at the workplace were also significant risk factors. The findings were similar when the analyses were confined to nonsmokers and were comparable across the major cell types of lung cancer.

Bias in learning disabilities placement

A nationally representative sample of 20,614 eighth grade students was examined for bias in placement decisions for children said to have learning disabilities. Factors investigated for bias were race, sex, and socioeconomic status. Path analysis showed significant and direct paths from sex and race to placement, controlling for socioeconomic status, academic ability, and behavioral competency. Boys were overrepresented in such classes beyond what their somewhat lower academic and behavioral competencies would predict. Caucasians were similarly overrepresented controlling for other variables in the model. It appears that boys and Caucasians are overrepresented in learning disabilities placements on a national scale even when other contributing factors are controlled.

Identification of novel loci affecting entry of Salmonella enteritidis into eukaryotic cells

There are an estimated 2 million cases of salmonellosis in the United States every year. Unlike the incidence of many infectious diseases, the incidence of salmonellosis in the United States and other developed countries has been rising steadily over the past 30 years, and the disease now accounts for 10 to 15% of all cases of acute gastroenteritis in the United States. The infecting organism is ingested and must traverse the intestinal epithelium to reach its preferred site for multiplication, the reticuloendothelial system. Despite several recent studies, the genetic basis of the invasion process is poorly understood. An emerging theme from these studies is that wild-type Salmonella organisms probably have several chromosomal loci that are required for the most efficient level of invasion. In this study, we have identified and characterized 13 TnphoA insertion mutants of Salmonella enteritidis CDC5 that exhibit altered invasion phenotypes. The mutants were identified by screening a bank of TnphoA insertions in S. enteritidis CDC5str for their invasion phenotype in three tissue culture cell lines (HEp-2, CHO, and MDCK). These 13 mutants were separated into six classes based on their invasive phenotypes in the tissue culture cell lines. Several mutants were defective for entry of some cell lines but not for others, while two mutants (SM6 and SM7) were defective for entry into all three tissue culture cell lines. This suggests that Salmonella spp. may express more than one invasion pathway. Southern analysis and chromosomal mapping indicated that as many as nine chromosomal loci may contribute to the invasion phenotype. It is becoming clear that the invasive phenotype of Salmonella spp. is multifactorial and more complex than that of some other invasive members of the family Enterobacteriaceae.

Mortality among dust-exposed Chinese mine and pottery workers

A cohort study of approximately 68,000 persons employed during 1972 to 1974 at metal mines and pottery factories in south central China was conducted to evaluate mortality from cancer and other diseases among workers exposed to different levels of silica and other dusts. A follow-up of subjects through December 31, 1989 revealed 6,192 deaths, a number close to that expected based on Chinese national mortality rates. There was, however, a nearly 6-fold increase in deaths from pulmonary heart disease (standard mortality ratio, 581; 95% confidence interval 538 to 626), and a 48% excess of mortality from nonmalignant respiratory diseases (standard mortality ratio, 148; 95% confidence interval, 139 to 158), primarily because of a more than 30-fold excess of pneumoconiosis. Pulmonary heart disease and noncancerous respiratory disease rates rose in proportion to dust exposure. Cancer mortality overall was not increased among the miners or pottery workers. There was no increased risk of lung cancer, except among tin miners, and trends in risk of this cancer with increasing level of dust exposure were not significant. Risks of lung cancer were 22% higher among workers with than without silicosis. The findings indicate that respiratory disease continues to be an occupational hazard among Chinese miners and pottery workers, but that cancer risks are not as yet strongly associated with work in these dusty trades.

Renal cell cancer among architects and allied professionals in Sweden

The Swedish Cancer-Environment Registry was used to evaluate a recent report of a large excess risk of renal cell cancer among architects in Los Angeles. We identified 131 renal cell cancers among male Swedish architects and allied professionals during a 19-year follow-up period (1961-1979). Compared with the Swedish population, there was no significant excess of renal cell cancer among architects and allied professionals (standardized incidence ratio (SIR) = 1.15; 131 cases). Although it was not possible to estimate the risk for architects alone, the SIR was only 1.06 (16 cases) in a subset of professionals employed in architectural and engineering firms. However, a significant increase in risk (SIR = 1.38) was observed in a related group of workers employed as engineers and construction supervisors in the home construction industry.

Incidence of childhood cancer in twins

The incidence of childhood cancer in twins was evaluated by linking a roster of 30,925 twins born in Connecticut (United States) between 1930 and 1969 with the Connecticut Tumor Registry. Cancer, exclusive of nonmelanoma skin cancer, was identified in 19 females and 12 males under 15 years of age. The incidence rate among twins was 7.9 cancers per 100,000 person-years (PY) overall, and 9.7 and 6.1 per 100,000 PYs for females and males, respectively. Four of 13 leukemias occurred in two female twin pairs, representing concordance rates of 18 percent overall and 29 percent for like-sex pairs, which are somewhat higher than values reported previously. The number of cancers expected was computed on the assumption that twins experienced the same sex-, age-, and calendar time-specific cancer rates as recorded for all Connecticut-born children. Because active follow-up of individuals was not conducted, an adjustment to person-years of observation was made to account for childhood mortality, including the high perinatal mortality characteristic of twins. Childhood cancer was 30 percent less frequent than expected (standardized incidence ratio [SIR] = 0.7; 95 percent confidence interval [CI] = 0.5-0.9), a deficit that is marginally greater than those found in previous studies. Both leukemia (SIR = 0.8; CI = 0.4-1.4), and all other cancers combined (SIR = 0.6; CI = 0.3-0.9) occurred less often than expected. The deficit was greater among males (SIR = 0.5; CI = 0.2-0.8) than among females (SIR = 0.9; CI = 0.5-1.4) and was especially pronounced among males younger than five years (SIR = 0.2; CI = 0.0-0.7). The data support the view that twins, particularly male twins, have a lower risk of childhood cancer than single-born children. Any added risk for twins associated with their greater frequency of exposure to prenatal X-rays appears to have been insufficient to offset an 'effect' of twinning per se. Possible explanations for this finding include (i) the low birthweight distribution of twins, or (ii) selective early mortality of twin fetuses or neonates who would otherwise have developed a clinical cancer.

Therapeutic radiation at a young age is linked to secondary thyroid cancer. The Late Effects Study Group

We estimated the risk of thyroid cancer among 9170 patients who had survived 2 or more years after the diagnosis of a cancer in childhood. As compared with the general population, patients had a 53-fold increased risk (95% confidence interval, 34-80). Risk increased significantly with time since treatment for the initial cancer (P = 0.03). Detailed treatment data were obtained for 23 cases and 89 matched controls from the childhood cancer cohort. Sixty-eight % of the thyroid cancers arose within the field of radiation. Radiation doses to the thyroid of greater than 200 cGy were associated with a 13-fold increased risk (95% confidence interval, 1.7-104). The risk of thyroid cancer rose with increasing dose (P less than 0.001), but this was derived almost entirely from the increase from less than 200 to greater than 200 cGy. The risk of thyroid cancer did not decrease, however, at radiation doses as high as 6000 cGy.

Correlates of liver cancer mortality in China

To provide clues to the causes of liver cancer in China, we studied the correlation of certain dietary and biochemical markers with liver cancer mortality across 65 Chinese counties. Mortality rates were significantly linked to the county-wide prevalence of hepatitis-B surface antigen positivity. Rates were also higher in counties with high plasma levels of total cholesterol and high consumption of liquor, rapeseed oil, and mouldy corn, while inverse associations were observed for wheat consumption. All of the observed associations, except those with cholesterol and rapeseed oil, were more pronounced in men than in women. No significant correlations with liver cancer mortality were found for consumption of several other foods; plasma levels of retinol, beta-carotene, alpha-tocopherol, selenium, zinc and ferritin; or urine levels of aflatoxin B1. Although causal inferences cannot be derived, this ecological study suggests that chronic infection with hepatitis-B virus contributes to the substantial variation in liver cancer mortality in China, and provides leads for further studies into the role of dietary and nutritional determinants.

Lung cancer among women in north-east China

A case-control study of lung cancer involving interviews with 965 female patients and 959 controls in Shenyang and Harbin, two industrial cities which have among the highest rates of lung cancer in China, revealed that cigarette smoking is the main causal factor and accounted for about 35% of the tumours among women. Although the amount smoked was low (the cases averaged eight cigarettes per day), the percentage of smokers among women over age 50 in these cities was nearly double the national average. Air pollution from coal burning stoves was implicated, as risks of lung cancer increased in proportion to years of exposure to 'Kang' and other heating devices indigenous to the region. In addition, the number of meals cooked by deep frying and the frequency of smokiness during cooking were associated with risk of lung cancer. More cases than controls reported workplace exposures to coal dust and to smoke from burning fuel. Elevated risks were observed for smelter workers and decreased risks for textile workers. Prior chronic bronchitis/emphysema, pneumonia, and recent tuberculosis contributed significantly to lung cancer risk, as did a history of tuberculosis and lung cancer in family members. Higher intake of carotene-rich vegetables was not protective against lung cancer in this population. The findings were qualitatively similar across the major cell types of lung cancer, except that the associations with smoking and previous lung diseases were stronger for squamous/oat cell cancers than for adenocarcinoma of the lung.

Indoor radon and lung cancer in China

Radon has long been known to contribute to risk of lung cancer, especially in undergound miners who are exposed to large amounts of the carcinogen. Recently, however, lower amounts of radon present in living areas have been suggested as an important cause of lung cancer. In an effort to clarify the relationship of low amounts of radon with lung cancer risk, we placed alpha-track radon detectors in the homes of 308 women with newly diagnosed lung cancer and 356 randomly selected female control subjects of similar age. Measurements were taken after 1 year. All study participants were part of the general population of Shenyang, People's Republic of China, an industrial city in the northeast part of the country that has one of the world's highest rates of lung cancer in women. The median time of residence in the homes was 24 years. The median household radon level was 2.3 pCi/L of air; 20% of the levels were greater than 4 pCi/L. Radon levels tended to be higher in single-story houses or on the first floor of multiple-story dwellings, and they were also higher in houses with increased levels of indoor air pollution from coal-burning stoves. However, the levels were not higher in homes of women who developed lung cancer than in homes of controls, nor did lung cancer risk increase with increasing radon level. No association between radon and lung cancer was observed regardless of cigarette-smoking status, except for a nonsignificant trend among heavy smokers. No positive associations of lung cancer cell type with radon were observed, except for a nonsignificant excess risk of small cell cancers among the more heavily exposed residents. Our data suggest that projections from surveys of miners exposed to high radon levels may have overestimated the overall risks of lung cancer associated with levels typically seen in homes in this Chinese city. However, further studies in other population groups are needed to clarify the carcinogenic potential of indoor radon.

Smoking, air pollution, and the high rates of lung cancer in Shenyang, China

A case-control study involving interviews with 1,249 patients with lung cancer and 1,345 population-based controls was conducted in Shenyang, an industrial city in northeastern China, where mortality rates are high among men and women. Cigarette smoking was found to be the principal cause of lung cancer in this population, accounting for 55% of the lung cancers in males and 37% in females. The attributable risk percentage among females is high compared to elsewhere in China, largely because of a higher prevalence of smoking among women. After adjustment for smoking, there were also significant increases in lung cancer risk associated with several measures of exposure to air pollutants. Risks were twice as high among those who reported smoky outdoor environments, and increased in proportion to years of sleeping on beds heated by coal-burning stoves (kang), and to an overall index of indoor air pollution. Threefold increases in lung cancer risk were found among men who worked in the nonferrous smelting industry, where heavy exposures to inorganic arsenic have been reported. The associations with both smoking and indoor air pollution were stronger for squamous cell and small cell carcinomas than for adenocarcinoma of the lung. Risks due to smoking or air pollution were not greatly altered by adjustment for consumption of fresh vegetables or sources of beta carotene or retinol, prior chronic lung diseases, or education level. The findings suggest that smoking and environmental pollution combine to account for the elevated rates of lung cancer mortality in Shenyang.

The Danish case-control study of cutaneous malignant melanoma. III. Hormonal and reproductive factors in women

The relationship between cutaneous malignant melanoma in women and reproductive and hormonal factors was investigated in a population-based case-control study including a total of 280 cases and 536 controls from East Denmark. Patients with lentigo maligna melanoma were not included. No association was found between risk of melanoma and age at menarche, duration of menstrual life, age at natural menopause, age at first pregnancy, or number of pregnancies, live births or miscarriages. There was no evidence of an association between melanoma and use, duration of use or type of oral contraceptives. The use of menopausal replacement therapy was not a risk factor for melanoma. There was no difference in risk associated with hormonal factors between superficial spreading melanoma and nodular melanoma. Our findings suggest that neither reproductive nor hormonal factors increase the risk of melanoma in women in Denmark.

The Danish case-control study of cutaneous malignant melanoma. IV. No association with nutritional factors, alcohol, smoking or hair dyes

In a population-based case-control study from East Denmark including 474 cases with cutaneous malignant melanoma and 926 controls we evaluated the influence of diet, alcohol, smoking, bathing habits and hair dyes on the risk of this cancer. Patients with lentigo maligna melanoma were not included. We observed no effect of dietary factors on risk of melanoma. No association was found between risk of melanoma and alcohol intake, tobacco smoking, bathing habits or hair dye use.

The Danish case-control study of cutaneous malignant melanoma. II. Importance of UV-light exposure

A population-based case-control study of 474 patients with cutaneous malignant melanoma and 926 population controls, conducted in East Denmark over a 3-year period, included an evaluation of the relationship of UV-light exposure to cutaneous melanoma risk. Patients with lentigo maligna melanoma were not included. Significantly increased risk was associated with severe sunburn before age 15 (RR = 2.7 for 5 + vs. never), sunbathing (RR = 1.6), boating (RR = 1.4) and vacations spent in the sun (RR = 1.4 for very sunny vs. never). A significant decrease in risk was associated with occupational exposure during the summer in males (RR = 0.7), and no association with cutaneous microtopography was seen. These findings were independent of the effects of constitutional risk factors (naevi, freckles and light hair colour). No association was found between the risk of cutaneous melanoma and exposure to artificial UV-light (fluorescent light, sun lamps, or sun beds). No significant difference was found between superficial spreading melanoma and nodular melanoma with regard to any of the sun exposure variables. Our data indicate that exposure to intermittent intense sunlight is an important risk factor for cutaneous malignant melanoma, while long-term continuous exposure does not appear to be risk factor.

Geographic pattern of lung cancer in Japan and its environmental correlations

Standardized lung cancer mortality ratios, 1969-1978, for basic administrative units of Japan were related to various environmental characteristics by multiple regression analysis. Elevated lung cancer mortality was demonstrated in the areas along the sea coast, particularly those with fishing ports, low socioeconomic status, and high level of air pollution. High mortality was also observed in coal mining areas and areas with shipyards. Data on tobacco expenditures provided partial adjustment for the effects of cigarette smoking on these correlations.

The Danish case-control study of cutaneous malignant melanoma. I. Importance of host factors

The relationship between cutaneous malignant melanoma and possible host factors was investigated in a population-based case-control study from East Denmark over a 3-year period. A total of 474 melanoma patients and 926 population controls aged 20-79 years were interviewed. Patients with lentigo maligna melanoma were not included. The major constitutional risk factors were: number of raised naevi on the arms (RR = 5.1 for 5+ vs. none), degree of freckling (RR = 2.9 for many vs. none), and light hair colour (RR = 1.7 for blond/fair vs. dark brown/black), which were independent of one another. An apparent synergy between number of raised naevi on the arms and degree of freckling was found. Thus, persons at high risk of melanoma may be identified by a simple assessment of naevi and degree of freckling. No significant difference was found between superficial spreading melanoma and nodular melanoma with regard to the most important host factors.

An examination of the Wechsler Adult Intelligence Scale (WAIS) subtests from a neuropsychological perspective

Individual subtest scores of the Wechsler Adult Intelligence Scale (WAIS) were regressed on measures of the Halstead-Reitan Neuropsychological Battery (HRNB) for 408 psychiatric and neurologic patients. The results suggested that language skills (Aphasia Screening Test), auditory attention (Seashore Rhythm Test), psychomotor speed and general cognitive functioning (Category Test) were underlying the performance in the majority of WAIS subtests. A canonical correlation was performed to consider the degree of commonality between the WAIS and the HRNB. One significant canonical correlation between the linear components of the WAIS and HRNB tests emerged. Canonical variates showed that Block Design, Digit Symbol, and Similarities subtests of the WAIS overlapped with the Aphasia Screening Test and the Category Test of the HRNB. It was concluded that, while shared variance does exist between the WAIS and the HRNB, each offers nonredundant information regarding neuropsychological functioning.

Multiple myeloma and occupation in Sweden

The occurrence of multiple myeloma by occupational and industrial category was systematically assessed using the Swedish Cancer-Environment Registry, which links cancer incidence (1961-1979) with occupational data from the 1960 census. Incidence of multiple myeloma was significantly increased for a number of occupational groups such as farmers, smelter and metallurgy workers, and miners-quarrymen-rock blasters. Although caution must be applied in drawing causal inferences, this national linked-registry analysis may provide clues to the environmental determinants of multiple myeloma.

Leukemias and occupation in Sweden: a registry-based analysis

A linked-registry was used to examine systematically, on a national basis, the leukemia incidence in Swedish men by industry and occupation. New associations were observed for chronic lymphocytic leukemia among cloth and pattern cutters and for chronic myelocytic leukemia among brewery workers and motor mechanics. A number of additional findings were consistent with previous observations in other countries. Although etiologic inferences are limited when using linked-registry data, this hypothesis-generating study may provide new clues to the occupational determinants of specific forms of leukemia.

Occupational risks for bladder cancer among men in Sweden

With the use of the Swedish Cancer-Environment Registry, census data on employment in 1960 were linked with registry data on bladder cancer during 1961-79. This hypothesis-generating study revealed for the first time associations between bladder cancer and employment in pulp and fiberboard manufacturing, in rope and twine making, and work as a dental technician. Statistically significant increases in risk were also found for several occupations previously associated with bladder cancer, including barbers and beauticians, artistic painters, toolmakers and machinists, and physicians, and employment in butcher shops, industrial chemical making, apparel manufacturing, and plumbing. Etiologic inferences cannot be made from this investigation, but the findings from this large national resource provide further clues to the occupational determinants of bladder cancer.

Bone sarcomas linked to radiotherapy and chemotherapy in children

We estimated the risk of subsequent bone cancer among 9170 patients who had survived two or more years after the diagnosis of a cancer in childhood. As compared with the general population, the patients had a relative risk of 133 (95 percent confidence interval, 98 to 176) and a mean (+/- SE) 20-year cumulative risk of 2.8 +/- 0.7 percent. Detailed data on treatment were obtained on 64 patients in whom bone cancer developed after childhood cancer. As compared with 209 matched controls who had survived cancer in childhood but who did not have bone cancer later, patients who had had radiation therapy had a 2.7-fold risk (95 percent confidence interval, 1.0 to 7.7) and a sharp dose-response gradient reaching a 40-fold risk after doses to the bone of more than 6000 rad. The relative dose-response effect among patients who had been treated for retinoblastoma resembled that among patients with all other types of initial tumors, although the cumulative risk of bone cancer in the retinoblastoma group was higher. Similar numbers of patients were treated with orthovoltage and megavoltage; the patterns of risk among categories of doses did not differ according to the type of voltage. After adjustment for radiation therapy, treatment with alkylating agents was also linked to bone cancer (relative risk, 4.7; 95 percent confidence interval, 1.0 to 22.3), with the risk increasing as cumulative drug exposure rose. We conclude that both radiotherapy and chemotherapy with alkylating agents for childhood cancer increase the subsequent risk of bone cancer.

Leukemia after therapy with alkylating agents for childhood cancer

The risk of leukemia was evaluated in 9,170 2-or-more-year survivors of childhood cancer in the 13 institutions of the Late Effects Study Group. Secondary leukemia occurred in 22 nonreferred individuals compared to 1.52 expected, based on general population rates [relative risk (RR) = 14; 95% confidence interval (CI), 9-22]. The influence of therapy for the first cancer on subsequent leukemia risk was determined by a case-control study conducted on 25 cases and 90 matched controls. Treatment with alkylating agents was associated with a significantly elevated risk of leukemia (RR = 4.8; 95% CI, 1.2-18.9). A strong dose-response relationship was also observed between leukemia risk and total dose of alkylating agents, estimated by an alkylator score. The RR of leukemia reached 23 in the highest dose category. Radiation therapy, however, did not increase risk. Although doxorubicin was also identified as a possible risk factor, the excess risk of leukemia following treatment for childhood cancer appears almost entirely due to alkylating agents.

Occupational risks for renal cancer in Sweden

A systematic assessment was made of the occurrence of renal cancer among men by industrial and occupational classification using the Cancer-Environment Registry, which links cancer incidence (1961-79) and census data (1960) with industry and occupation for all employed individuals in Sweden. Data were analysed separately for cancers of the renal parenchyma and pelvis. Significantly increased risks for renal cell cancer were observed for several professional and white collar occupations, including physicians and others in the health care industry. By contrast, the risks for renal pelvis cancer tended to be higher among blue collar workers, especially in the machine industry. Deficits of both cancers occurred among farmers. The findings of the survey are considered as aetiological clues that may deserve further study, although some associations support observations in other countries.