Reduced risk of hip fracture in women with endometrial cancer.

The effect of excessive endogenous oestrogens on the risk of hip fracture was investigated in a population-based cohort of 2111 women with endometrial carcinoma who were followed up from age 50 years regarding the occurrence of a first hip fracture. Overall, 77 cases of hip fracture were observed, as against 120.8 expected, which meant a significantly reduced relative risk, standardized incidence ratio (SIR) = 0.6, 95% confidence interval (CI): 0.5-0.8. This possible protective effect was significant for cervical fractures, SIR = 0.6 (95% CI: 0.4-0.8), but not for trochanteric, SIR = 0.8 (95% CI: 0.5-1.1). Age at endometrial cancer diagnosis was not a determinant of the risk of hip fracture. A lowered relative risk was present regardless of age at diagnosis and persisted during the entire follow-up period and into advanced ages. A case-control analysis within the cohort, and based on medical record data, indicated that a higher weight might be associated with a greater protective effect, as compared with a lower weight. Exposure to exogenous oestrogens was infrequent and could not have explained the present results. We conclude that persistent influence of oestrogens, notably of endogenous origin, can reduce the risk of hip fractures, and that this protective effect may be long-lasting and extend to advanced ages.     

Hip fractures in women with breast cancer

The authors investigated whether the incidence of first hip fracture, an indicator of osteoporosis, is lower in breast cancer patients, who are assumed to have higher levels of endogenous estrogens, than in other women. A population-based Swedish cohort comprising 9,673 women with invasive breast cancer diagnosed from 1958 through 1983 was followed up with respect to the occurrence of a first hip fracture during the period 1965-1983. Overall, the number of observed acute fractures (n = 387) was slightly higher than expected (n = 348.6) (standardized incidence ratio (SIR) = 1.1, 95% confidence interval (CI) 1.0-1.2). Risk for trochanteric fractures was slightly higher than expected (SIR = 1.2, 95% CI 1.0-1.4), but risk for cervical fractures was not (SIR = 1.0, 95% CI 0.9-1.1). Risk for trochanteric fracture decreased with increasing age at breast cancer diagnosis, reaching standardized incidence ratios close to unity after the age of 70 years. Duration of follow-up appeared to be unrelated to the risk of either type of fracture. The authors conclude that the incidence of first hip fracture is not lower in breast cancer patients than in other women.     

Cancer incidence in a cohort of infertile women

To explore further the relation between infertility and breast and female reproductive cancers, cancer incidence among 2,632 Israeli women treated for infertility between 1964 and 1974 was evaluated. Cancer incidence through December 1981 was determined by matching the study cohort to the Israel Cancer Registry. The observed number of cancers was compared with sex-age-ethnic and calendar-year, site-specific national cancer rates. There were 42 cancers observed compared with 37.4 expected, yielding a standardized incidence ratio of 1.1 (95% confidence interval (CI) = 0.8-1.5). Analysis by infertility diagnosis demonstrated no significant excess of total cancer incidence; the standardized incidence ratio was 1.3 (95% CI = 0.8-1.8) for infertility due to hormonal deficiency, 0.7 (95% CI = 0.3-1.4) for mechanical infertility, 1.6 (95% CI = 0.6-3.6) for infertility of the male partner, and 1.1 (95% CI = 0.5-2.2) for unclassified diagnosis. Site-specific analyses revealed a significantly increased risk (8.0; 95% CI = 2.5-19.3; four cases observed, 0.50 expected) of endometrial cancer for the hormonal group and a nonsignificant excess of breast cancer and melanoma. Although numbers were small, women with disorders causing unopposed estrogen production had a risk of 1.4 (95% CI = 0.8-2.2) for all cancer sites, which reached 10.3 (95% CI = 2.6-28.2; three cases observed, 0.29 expected) for endometrial cancer and 1.8 (95% CI = 0.8-3.4; eight cases observed, 4.43 expected) for breast cancer. Among women with nonhormonal infertility, there was a suggestion of increased risks of carcinoma of the ovary (3.2; 95% CI = 0.3-32.9; two cases observed, 0.63 expected) and thyroid (3.0; 95% CI = 0.3-24.6; two cases observed; 0.67 expected). No evidence of an association between ovulation-inducing drugs and cancer was found. This study supports the hypothesis that infertility caused by hormone deficiency is a risk factor for uterine cancer, but is inconclusive regarding breast cancer.     

Is there a reduced risk of breast cancer among women with hip fractures?

To test the hypothesis that osteoporosis, which results partly from long-term estrogen deficiency, is associated with a lowered risk of breast cancer, a population-based cohort study was performed in Amiens. To ascertain the incidence of breast cancer, 1300 women were followed through after a first hip fracture. Overall, 18 cases of cancer were observed cf. 21.8 expected (standardized incidence ratio (SIR): 0.82; 95% confidence interval (CI): 0.5–1.3). The results are consistent with previous studies which concluded that long-term estrogen deficiency is associated with a reduced risk of developing breast cancer.     

Cancer incidence among Icelandic deck officers in a population-based study

OBJECTIVES: The aim of this study was to define the cancer pattern in an Icelandic cohort of deck officers while indirectly controlling for their smoking habits. METHODS: A cohort of 3874 male deck officers was followed from 1966 to 1998. It was record-linked by the deck officers' personal identification numbers to population-based registers containing each person's vital and emigration status and cancer diagnosis. Standardized incidence ratios (SIR) were calculated for all cancers and different cancer sites in relation to different lag times and years of birth. Information on smoking habits was obtained by from a questionnaire administered to a sample of the cohort (N=728). RESULTS: In the total cohort 436 cancers were observed, equal to the expected 436 [SIR 1.0, 95% confidence interval (95% CI) 0.9-1.1], and a significantly increased risk of soft-tissue sarcoma (SIR 2.7, 95% CI 1.2-5.1) was found together with a decreased risk of testis cancer (SIR 0.0, 95% CI .. -0.7) and urinary bladder cancer (SIR 0.5, 95% CI 0.3-0.8). The deck officers' smoking habits were similar to those found in a sample of the general population. The predictive value was 1.11 for lung cancer CONCLUSIONS: An increased incidence of soft-tissue sarcoma was found among deck officers. This increase resembles that previously found for Swedish deck officers, and it warrants further study.     

Tubal sterilization and risk of ovarian, endometrial and cervical cancer. A Danish population-based follow-up study of more than 65 000 sterilized women

BACKGROUND: On the basis of a population-based cohort, we assessed the cancer risk, focusing on gynaecological cancers and pre-malignant lesions, among women with a previous tubal sterilization. METHODS: Using the Danish Hospital Discharge Register we identified 65 232 women who had a tubal sterilization (1977-1993). The cohort was followed for cancer occurrence, and compared with the expected number based on the national cancer incidence rates. RESULTS: The overall risk of ovarian cancer was decreased (standardized incidence ratio [SIR] = 0.82; 95% CI: 0.6, 1.0), and it was still decreased > or =10 years after the sterilization (SIR = 0.65; 95% CI: 0.4, 1.0). The rate of endometrial cancer was also decreased (SIR = 0.66; 95% CI: 0.5, 1.0), the risk continued being moderately reduced during follow-up, although it was not statistically significant. CONCLUSIONS: In this nationwide, population-based study we find that women with tubal sterilization have a decreased risk of subsequent development of ovarian cancer. As the protective effect is not decreasing with years of follow-up, our data do not support that 'screening' bias can explain the protective effect, but indicate that the sterilization itself may convey a reduction in risk. The same pattern is found for endometrial cancer, the association being less strong.     

Evaluation of mortality and cancer incidence among alachlor manufacturing workers.

Alachlor is the active ingredient in a family of preemergence herbicides. We assessed mortality rates from 1968 to 1993 and cancer incidence rates from 1969 to 1993 for manufacturing workers with potential alachlor exposure. For workers judged to have high alachlor exposure, mortality from all causes combined was lower than expected [23 observed, standardized mortality ratio (SMR) = 0.7, 95% CI, 0.4-1.0], cancer mortality was similar to expected (6 observed, SMR = 0.7, 95% CI, 0.3-1.6), and there were no cancer deaths among workers with 5 or more years high exposure and 15 or more years since first exposure (2.3 expected, SMR = 0, 95% CI, 0-1.6). Cancer incidence for workers with high exposure potential was similar to the state rate [18 observed, standardized incidence ratio (SIR) = 1.2, 95% CI, 0.7-2.0], especially for workers exposed for 5 or more years and with at least 15 years since first exposure (4 observed, SIR = 1.0, 95% CI, 0.3-2.7). The most common cancer for these latter workers was colorectal cancer (2 observed, SIR 3.9, 95% CI, 0.5-14.2 among workers). Despite the limitations of this study with respect to small size and exposure estimating, the findings are useful for evaluating potential alachlor-related health risks because past manufacturing exposures greatly exceeded those characteristic of agricultural operations. These findings suggest no appreciable effect of alachlor exposure on worker mortality or cancer incidence rates during the study period.     

Radioactive iodine therapy and breast cancer. A follow-up study of hyperthyroid women

A follow-up study of 1,762 hyperthyroid women who were treated at the Massachusetts General Hospital Thyroid Unit between 1946 and 1964 was conducted. The average length of follow-up was 17.2 years. A 1978 mailing address or a death certificate was located for 92% of the women, and 88% of 1,058 living patients responded to a mail questionnaire. The standardized mortality ratio (SMR) for all causes of death was 1.3 (95% confidence interval (CI) 1.2-1.4). The standardized mortality ratios for all malignant neoplasms and for breast cancer were 0.9 (95% CI 0.7-1.1) and 1.3 (95% CI 0.8-1.9), respectively. More deaths than expected were observed from endocrine and metabolic diseases (SMR = 1.8, 95% CI 1.2-2.7), circulatory system diseases (SMR = 1.4, 95% CI 1.3-1.6), and respiratory system diseases (SMR = 1.9, 95% CI 1.3-2.6). The standardized incidence ratios (SIR) for all malignant neoplasms and for breast cancer were 0.9 (95% CI 0.8-1.1) and 1.2 (95% CI 0.9-1.5), respectively. A nonsignificant excess breast cancer risk was observed 10 years after the onset of thyroid symptoms and was present at the end of 30 years of observation. A statistically significant excess number of pancreatic cancer cases (SIR = 2.0, 95% CI 1.0-3.7) and a nonsignificant excess of brain cancer cases (SIR = 2.3, 95% CI 0.7-5.3) were observed. Eighty per cent of the women were treated with radioactive iodine. When age at treatment and year of treatment were controlled, women who were ever treated with radioactive iodine had a standardized rate ratio for breast cancer of 1.9 (95% CI 0.9-4.1), compared with those who were never treated with radioactive iodine. Women who developed hypothyroidism as a result of their treatment for hyperthyroidism did not have an increased risk of developing breast cancer (SIR = 1.1, 95% CI 0.8-1.6).     

A prospective study in the Australian petroleum industry. II. Incidence of cancer.

This paper reports incidence of cancer in employees of the Australian petroleum industry from 1981 to 1989. Two surveys by personal interview incorporated more than 15,000 employees, representing 92% of the eligible population. Subjects were included in the analysis after completing five years of service in the industry. At the time of this report the cohort did not include sufficiently large numbers of women for useful analysis; results presented are restricted to the men. On 31 December 1989, 50,254 person-years of observation had accumulated in the men with 152 incident cancers reported. The standardised incidence ratio (SIR) analysis showed overall cancer rates close to those of the national population. Whereas deficits were seen in some cancer sites, notably lung cancer (SIR 0.5, 95% confidence internal (95% CI) 0.3-0.9), incidence rates for some other cancer sites suggested increased risk. An excess of observed over expected cases was present in all subcategories of lymphohaematopoietic cancer except Hodgkin's disease (no cases), and was most apparent in myeloid leukaemia (SIR 4.0, 95% CI 1.6-8.2). The other major site with a raised number of cases observed over expected was melanoma (SIR 1.4, 95% CI 0.8-2.1).     

A prospective study in the Australian petroleum industry. II. Incidence of cancer

This paper reports incidence of cancer in employees of the Australian petroleum industry from 1981 to 1989. Two surveys by personal interview incorporated more than 15,000 employees, representing 92% of the eligible population. Subjects were included in the analysis after completing five years of service in the industry. At the time of this report the cohort did not include sufficiently large numbers of women for useful analysis; results presented are restricted to the men. On 31 December 1989, 50,254 person-years of observation had accumulated in the men with 152 incident cancers reported. The standardised incidence ratio (SIR) analysis showed overall cancer rates close to those of the national population. Whereas deficits were seen in some cancer sites, notably lung cancer (SIR 0.5, 95% confidence internal (95% CI) 0.3-0.9), incidence rates for some other cancer sites suggested increased risk. An excess of observed over expected cases was present in all subcategories of lymphohaematopoietic cancer except Hodgkin's disease (no cases), and was most apparent in myeloid leukaemia (SIR 4.0, 95% CI 1.6-8.2). The other major site with a raised number of cases observed over expected was melanoma (SIR 1.4, 95% CI 0.8-2.1).     

Wood dust exposure and cancer incidence: a retrospective cohort study of furniture workers in Estonia

BACKGROUND: Occupational wood dust exposure is associated with increased risk of sinonasal cancer in men. However, little is known whether it is associated with sinonasal cancer in women or with malignancies of other sites. METHODS: In a retrospective cohort study of furniture workers, cancer incidence in 3723 men and 3063 women between 1968 and 1995 was compared to the incidence in the general population of Estonia. Cancer risks were analyzed by employment duration and occupation. RESULTS: The standardized incidence ratio (SIR) for all cancers did not differ significantly from one. Two men and one woman had sinonasal cancer (expected 1.07 and 0.53, respectively). Significantly increased risk of colon cancer was seen in the cohort (SIR 1.65, 95% confidence interval (CI) 1.22-2.17). Subjects employed for 10 years and over had significant excess of colon cancer (SIR 2.29, 95% CI 1.28-3.77) and rectal cancer (SIR 2.10, 95% CI 1.05-3.76) in the analysis by employment duration using exposure with a latency of 20 years. The nonsignificant excess of pharyngeal cancer in men (SIR 1.82) and lung cancer in women (SIR 1.43) was restricted to short-term workers. CONCLUSIONS: This study found an excess of colon and rectal cancer in furniture workers. There was no increase in total cancer risk.     

Gliomas among men employed in the Swedish pulp and paper industry

OBJECTIVES: This study investigated whether previous findings of an increased risk of gliomas among workers in some pulp and paper mills could be confirmed for all Swedish pulp and paper mill workers and whether the increase could be attributed to certain occupational groups. METHODS: The study was based on the Swedish Cancer Environment Register, which links the incidence of cancer from 1971 to 1990 and the 1960 and 1970 census data on codes of occupation and industry for the whole population. Standardized incidence ratios (SIR) were used to estimate the risks for men in different occupations in pulp (N = 28,142) and paper (N = 39,169) mills in 1960, 1970 or both years as compared with those of all gainfully employed men in Sweden. RESULTS: Maintenance workers employed in pulp or paper mills in 1960, 1970 or both years, as well aspulp workers, showed an increased incidence of gliomas in 1971-1990 [SIR 1.5, 95% confidence interval (95% CI) 1.1-2.1 and SIR 1.5,95% CI 1.0-2.2, respectively], whereas the incidence among process workers in paper mills was lower than expected (SIR 0.6, 95% CI 0.3-0.9). Taken together, all employed men in the pulp mill industry had an increased incidence of gliomas (SIR 1.3, 95% CI 1.0-1.7). CONCLUSIONS: Pulp mill workers, but not paper mill workers, were found to have more gliomas in 1971-1990 than expected. There was an increased risk of gliomas among maintenance workers in both pulp and paper mills. Few risk factors for brain tumors are recognized, and the causes of the increase are not obvious.     

Cancer among women textile workers in Shanghai, China: overall incidence patterns, 1989-1998

BACKGROUND: Cancer incidence in women textile workers has not been adequately studied. The aim of this study was to examine site-specific cancer incidence patterns in a cohort of 267,400 women textile workers in Shanghai, China. METHODS: Women employed by the Shanghai Textile Industry Bureau (STIB) were followed for cancer incidence from 1989 to 1998. Age-adjusted standardized incidence ratios (SIRs) and 95% confidence intervals (CI) were computed based on Shanghai Cancer Registry (SCR) rates. RESULTS: There was a decrease in cancer incidence for the cohort compared with urban Shanghai women (SIR = 0.91, 95% CI = 0.89-0.93). There were small increased risks of other endocrine tumors (SIR = 1.31, 95% CI = 1.02-1.65). There were decreased risks for esophageal (SIR = 0.54, 95% CI = 0.44-0.66), stomach (SIR = 0.79, 95% CI = 0.73-0.85), rectal (SIR = 0.88, 95% CI = 0.78-0.98), lung (SIR = 0.80, 95% CI = 0.74-0.86), cervical (SIR = 0.37, 95% CI = 0.28-0.50), ovarian (SIR = 0.85, 95% CI = 0.75-0.96), and bladder cancers (SIR = 0.63, 95% CI = 0.46-0.85). CONCLUSIONS: Women employed in the textile industry had a lower than expected cancer experience compared with urban Shanghai women. Further research on this cohort will examine associations between site-specific cancers and occupational exposures to dusts and chemicals.     

Incidence of cancer among anthophyllite asbestos miners in Finland.

A cohort of 736 male and 167 female workers of two anthophyllite mines in Finland was followed up through the Finnish Cancer Registry for cancer in 1953-91. Compared with the total cancer incidence of the east Finnish population, the men had a raised risk of total cancer (standardised incidence ratio (SIR) 1.7; 95% confidence interval (95% CI) 1.4-1.9), mainly attributable to an excess in lung cancer (SIR 2.8; 95% CI 2.2-3.6). The risk of lung cancer was somewhat higher among workers classified as heavily exposed (SIR 3.2; 95% CI 2.4-4.1) than among those moderately exposed (SIR 2.3; 95% CI 1.5-3.6) and the risk increased with increasing smoking and with increasing time of work with exposure. There were four cases of mesothelioma v 0.1 expected, all in men who smoked and had had a long and heavy asbestos exposure. Among women, a non-significant excess in total cancer (SIR 1.5; 95% CI 0.9-2.4) was found in the subgroup with heavy exposure to asbestos. Anthophyllite asbestos seems to have high potency in the carcinogenesis of lung cancer and low potency in carcinogenesis of mesothelioma in comparison with the other types of asbestos.     

Cancer incidence among farmers exposed to lindane while sheep dipping

OBJECTIVES: The objective of this study was to determine whether site-specific cancer incidence among farmers exposed to the insecticide lindane (g-hexachlorocyclohexane) while dipping sheep differs from that of the general population in Iceland. METHODS: Cohorts of 7882 men and 429 women, who, according to records on sheep dipping, were sheep owners, were followed from 1962 to 2003 in the Cancer Registry for cancer incidence. The observed number of cancers was compared with expected values, calculated on the basis of person-years of risk and cancer incidence in the general population of Iceland. RESULTS: For men the standardized incidence ratio (SIR) for all cancer sites was 0.79, with a 95% confidence interval (95% CI) of 0.76-0.83. For both the men and the women a significantly increased risk for lip cancer was found, with SIR of 1.50 (95% CI 1.08-2.04) and 9.09 (95% CI 1.02-32.82), respectively. The SIR for several cancer sites were lower than unity for both the men and women. Examples were cancers of the colon, rectum, pancreas, stomach, lungs, kidney, bladder, and brain and nervous system. CONCLUSIONS: The decreased risk of most cancers among these sheep farmers agrees with findings reported previously among farmers from other countries, as well as in Iceland. Cancer of the lip was the only cancer type in significant excess among both genders, and the stomach cancer rates were near unity, but, in previous studies on Icelandic farmers, an increase had been found for stomach cancer. The site-specific cancer incidence for sheep-dipping farmers did not differ substantially from that of the general population.     

Cancer incidence among Norwegian airline cabin attendants

BACKGROUND: Cabin crews are exposed to cosmic radiation at work and this may increase their incidence of radiation-induced cancers. Former studies indicate an increased risk of breast cancer. METHODS: A retrospective cohort study was performed. The cohort was established from the files of the Civil Aviation Administration and included people with a valid licence as a cabin attendant between 1950 and 1994. The cohort was linked to the Cancer Registry of Norway. Observed number of cases was compared with expected, based on national rates. Breast cancer incidence was analysed, adjusting for individual fertility variables. RESULTS: A group of 3693 cabin attendants were followed over 72 804 person-years. Among the women, 38 cases of breast cancer were observed (standardized incidence ratio (SIR) = 1.1, 95% CI : 0.8-1.5). Among men excess risks were found for cancers in the upper respiratory and gastric tract (SIR = 6.0, 95% CI : 2.7-11.4) and cancer of the liver (two cases, SIR = 10.8, 95% CI : 1.3-39.2). For both sexes elevated risks were found for malignant melanoma and non-melanoma skin cancer; for men these were SIR = 2.9 (95% CI : 1.1-6.4) and SIR = 9.9 (95% CI : 4.5-18.8) respectively, while for women these were SIR = 1.7 (95% CI : 1.0-2.7) and SIR = 2.9 (95% CI : 1.0-6.9) respectively. For no cancer site was a significant decreased risk found. CONCLUSIONS: An increased risk of radiation-induced cancers was not observed. The excess risks of some other cancers are more probably explained by factors related to lifestyle.     

Mortality and cancer incidence among Lithuanian cement producing workers

Aims: To investigate mortality and cancer incidence of cement producing workers.

Methods: A total of 2498 cement workers who have been employed at Portland cement producing departments for at least one year from 1956 to 2000 were followed up from 1 January 1978 to 31 December 2000. The cohort contributed 43 490 person-years to the study. Standardised incidence ratios (SIR) and standardised mortality ratios (SMR) were calculated as ratios between observed and expected numbers of cancers and deaths. The expected numbers were based on sex specific incidence and mortality rates for the total Lithuanian population.

Results: Significantly increased SMRs were found for all malignant neoplasms (SMR 1.3, 95% CI 1.0 to 1.5) and for lung cancer (SMR 1.4, 95% CI 1.0 to 1.9) among male cement workers. SIR for all cancer sites was 1.2 (95% CI 1.0 to 1.4). Excess risk was found for cancer of the lung (SIR 1.5, 95% CI 1.1 to 2.1). The SIR for urinary bladder cancer was also increased (SIR 1.8, 95% CI 0.9 to 3.5). The overall cancer incidence was not increased among females (SIR 0.8, 95% CI 0.6 to 1.1). With increasing cumulated exposure to cement dust, there were indications of an increasing risk of lung and stomach cancers among males.

Conclusions: This study supported the hypothesis that exposure to cement dust may increase the lung and bladder cancer risk. A dose related risk was found for stomach cancer, but no support was found for an increased risk of colorectal cancer.

     

Hip fractures among infertile women

A retrospective cohort study was conducted in a population-based inception cohort of 1,157 Olmsted County, Minnesota, women with infertility (failure to conceive after 1 year despite intercourse without contraception) that was first diagnosed at the Mayo Clinic (Rochester, Minnesota) between 1935 and 1964. In this relatively young cohort, 31 hip fractures were observed during 35,849 person-years of follow-up; 36.5 had been expected (standardized incidence ratio = 0.85, 95% confidence interval 0.58-1.20). Standardized incidence ratios did not differ by type or cause of infertility. The data suggested that women with consistently irregular menses may have a greater risk of hip fracture. This finding should be confirmed by additional studies with longer follow-up periods and with assessment of other fracture outcomes.     

Hip fractures in Norway 1999–2008: time trends in total incidence and second hip fracture rates. A NOREPOS study

Declining incidences of hip fractures are reported from western countries. Norway has among the highest rates in the world. The aim of this study was to investigate trends in total hip fracture rates in Norway between 1999 and 2008 and risk of second hip fractures. All hospitalizations given a hip fracture diagnosis code (International Classification of Diseases (ICD) 9 or ICD 10) (cervical, trochanteric or subtrochanteric) in Norwegian hospitals were retrieved with accompanying surgical procedure codes and additional diagnoses. A total of 93,123 hip fractures were identified between 1999 and 2008 in persons ≥50?years. Annual incidences of hip fractures were calculated and tested for trends. Rates of first and second hip fractures (2006–2008) were compared. The age-standardized total incidence of hip fracture decreased by 13.4?% (95?% confidence interval (CI): 11.0–15.6) in women and 4.8?% (95?% CI: 0.7, 8.7) in men. Age-adjusted rates of second hip fractures did not change in the observation period. In those with a prior hip fracture, the age-standardized risk of a subsequent hip fracture was 2.5-fold (95?% CI: 2.5, 2.6) in women, and 4.6-fold (95?% CI: 4.5, 4.7) in men. Total hip fracture rates declined in both genders during 1999–2008, whereas rates of second hip fractures did not change.