Do tanning lamps cause melanoma? An epidemiologic assessment

Sun exposure is a known cause of melanoma, and there are several reasons for concern that tanning lamp use may also cause melanoma, especially because of the spectral output of the lamps,the similarity of tanning lamp use to natural sun exposure (particularly sunbathing), the reported association of melanoma with PUVA therapy, and the positive results in several case-control studies of melanoma risk and tanning lamp use. We have reviewed the epidemiologic literature relevant to the relation between tanning lamp use and melanoma and have discussed methodologic issues that should be considered in interpreting these reports and designing improved studies. Although several investigations have found a positive relation between tanning lamp use and melanoma, in some instances including dose-response or duration-response effects, the methodologic limitations preclude any firm conclusion regarding a causative relation. Meta-analysis of existing data may provide better information, but several limitations could only be overcome by new studies collecting more precise exposure data. The popularity of tanning lamp use, especially in young persons, adds urgency to the quest for elucidation of the relation between the use of these devices and melanoma risk.

Risks of breast and testicular cancers in young adult twins in England and Wales: evidence on prenatal and genetic aetiology

BACKGROUND

Aetiology of breast and testicular cancers may have prenatal factors, possibly exposure of the fetus to high concentrations of maternal oestrogen. Dizygotic twinning probably involves high hormone concentrations, and therefore, dizygotic twins might be at raised risk of these cancers. The aetiologies of breast and testicular cancers have genetic components, for breast cancer, especially at younger ages. Twins of these probands may, therefore, be at high risk. We investigated risk in twins of patients with breast cancer at young ages or with testicular cancer.

METHODS

We identified twins with breast cancer incident at ages younger than 45 years and with incident testicular cancer in England and Wales during 1971-89 by cross-matching national cancer-registration and births records. We determined zygosity by questionnaires to the patients. The twins of probands were followed up for cancer incidence and death. We analysed risks of breast and testicular cancer in dizygotic twins compared with monozygotic twins, and in monozygotic and dizygotic twins of probands.

FINDINGS

We identified 500 twins with breast cancer and 194 with testicular cancer. We found a non-significantly raised risk of breast cancer in dizygotic compared with monozygotic twins younger than 30 years (odds ratio 2.3 [95% CI 0.9-5.9]) but not older. The overall risk of testicular cancer was significantly higher in dizygotic twins than in monozygotic twins (1.5 [1.1-2.2]) consequent on a risk for seminomas was high (3.2 [1.6-6.5]; p = 0.001). Risk of breast cancer was significantly raised in female twins of probands (standardised incidence ratio 7.7 [4.9-12.2], p < 0.001). The relative risk of breast cancer was 34.7 (9.5-126.5) in monozygotic twins of women in whom breast cancer had occurred before age 35 years. The cumulative risk of breast cancer for these twins by age 40 years was 29% (13-56). The relative risk of testicular cancer was 37.5 (12.3-115.6) in twins of men with testicular cancer. The cumulative risk by age 40 years in monozygotic twins of men with testicular cancer was 14% (4-46).

INTERPRETATION

The higher risks of these cancers in dizygotic than in monozygotic twins support a prenatal aetiology, and are compatible with aetiology related to raised maternal concentrations of free, unbound oestrogens. The results for twins of probands have implications for genetic aetiology; appropriate clinical action for monozygotic twins needs consideration.

A nested case-control study of fatal work related injuries among Brazilian steel workers

OBJECTIVES

To estimate the relative risk of death from work related injury in a steelworks, associated with exposure to various occupational hazards, sociodemographic factors, and medical history.

MATERIAL AND METHODS

The study was a nested case-control design. It was based on a cohort of men employed in the steel plant of USIMINAS, Brazil between January 1977 and August 1990, who were followed up to November 1992. The cases were defined as all workers in the cohort who died from injury in the study period and whose death had been notified to the Brazilian Ministry of Labour as being related to work. Four controls per case, matched to cases on year of birth, were randomly selected from among workers employed in the plant at the time of death of the matching case. Data on potential risk factors for occupational injury were extracted from company records; for the controls these data were abstracted for the period preceding the death of the matching case.

RESULTS

There were 37 deaths related to work injuries during the study period. Four surviving workers were selected as controls for each case, but for eight the personnel records were incomplete, leaving 140 controls in all. Significantly increased risk of fatal injury related to work was associated with exposure to noise, heat, dust and fumes, gases and vapours, rotating shift work, being a manual worker, and working in the steel mill, coke ovens, blast furnaces, and energy and water supply areas. Risk of fatal injury related to work increased with intensity of exposure to noise (P (trend) = 0.004) and heat (P < 0.001), and increased greatly with a hazard score that combined information on noise, heat, dust, and gas exposure (P < 0.001). Number of years of schooling (P = 0.03) and salary level (P = 0.03) were both negatively associated with risk. In a multivariate analysis including all these significant factors, only hazard score and area of work remained associated with death from injury related to work. The highest risks were for men exposed to all four environmental hazards (odds ratio (OR) 19.4; 95% confidence interval (95% CI) 1.1 to 352.1) and those working in the energy supply area (OR 18.0; 1.6 to 198.1).

CONCLUSIONS

The study identified parts of the steelworks and types of hazard associated with greatly increased risk of fatal accident. Research and measures to prevent accidents need to concentrate on these areas and the people working in them. The use of a hazard score was successful in identifying high risk, and similar scoring might prove useful in other industrial situations.

Risk of death from motor-vehicle injury in Brazilian steelworkers: a nested case-control study

OBJECTIVES

In a cohort of 21,816 Brazilian steelworkers we found mortality from motor-vehicle injury was twice that in the State population. A nested case-control study was therefore undertaken to investigate possible socio-demographic, medical and occupational risk factors for this increased risk.

METHODS

Cases were defined as all steelworkers in the cohort who died of motor-vehicle injury during employment in the period 1977-1992. For each case, four controls were selected at random from workers in the cohort who were employed at the time of death of the case, and who were born in the same year as the case. Data on socio-demographic factors, and medical and occupational histories were obtained from personnel, industrial hygiene and medical records, and the relation of these factors to risk of motor-vehicle injury was analysed using conditional logistic regression.

RESULTS

In a multivariate analysis, the risk of death from motor-vehicle injury was independently associated with being unmarried (odds ratio [OR] compared to married = 3.21, 95% confidence interval [CI]: 1.84-5.59), having a hearing defect (OR = 2.28, 95% CI: 1.10-4.74) and exposure to moderate (OR = 1.71, 95% CI: 1.03-2.83) or high (OR = 2.00, 95% CI: 1.18-3.39) levels of noise at work. The risk of fatal motor-vehicle injury increased with intensity of occupational noise exposure (P = 0.004).

CONCLUSIONS

The raised risk of motor-vehicle injury death associated with single marital status is likely to relate to selective factors in the types of individual who remain single, and behaviours associated with being unmarried. The raised risks in relation to hearing defects and exposure to occupational noise, factors that do not appear to have been examined previously, imply that occupational noise exposures might be a cause of fatal motor-vehicle accidents outside the workplace. This finding may have widespread public health consequences since high levels of noise in the workplace and occupationally acquired hearing deficits are prevalent in several occupations. Further investigation is needed to confirm the associated and its mechanisms and, if it is causal, to develop preventive strategies.

Mortality of doctors in different specialties: findings from a cohort of 20000 NHS hospital consultants

OBJECTIVES

To examine patterns of cause specific mortality in NHS hospital consultants according to their specialty and to assess these in the context of potential occupational exposures.

METHODS

A historical cohort assembled from Department of Health records with follow up through the NHS Central Register involving 18,358 male and 2168 female NHS hospital consultants employed in England and Wales between 1962 and 1979. Main outcome measures examined were cause specific mortality during 1962-92 in all consultants combined, and separately for 17 specialty groups, with age, sex, and calendar year adjusted standardised mortality ratios (SMRs) for comparison with national rates, and rate ratios (RRs) for comparison with rates in all consultants combined.

RESULTS

The 2798 deaths at ages 25 to 74 reported during the 30 year study period were less than half the number expected on the basis of national rates (SMR 48, 95% confidence interval (95% CI) 46 to 49). Low mortality was evident for cardiovascular disease, lung cancer, other diseases related to smoking, and particularly for diabetes (SMR 14, 95% CI 6 to 29). Death rates from accidental poisoning were significantly raised among male consultants (SMR 227, 95% CI 135 to 359), the excess being most apparent in obstetricians and gynaecologists (SMR 934); almost all deaths from accidental poisoning involved prescription drugs. A significantly raised death rate from injury and poisoning among female consultants was due largely to a twofold excess of suicide (SMR 215, 95% CI 93 to 423), the rate for this cause being significantly raised in anaesthetists (SMR 405). Compared with all consultants, significantly raised mortality was found in psychiatrists for all causes combined (RR 1.12), ischaemic heart disease (RR 1.18), and injury and poisoning (RR 1.46); in anaesthetists for cirrhosis (RR 2.22); and in radiologists and radiotherapists for respiratory disease (RR 1.68). There were significant excesses of colon cancer in psychiatrists (RR 1.67, compared with all consultants) and ear, nose, and throat surgeons (RR 2.25); melanoma in anaesthetists (RR 3.33); bladder cancer in general surgeons (RR 2.40); and laryngeal cancer in ophthalmologists (RR 7.63).

CONCLUSIONS

Lower rates of smoking will have contributed substantially to the low overall death rates found in consultants, but other beneficial health related behaviours, and better access to health care, may have also played a part. The increased risks of accidental poisoning in male consultants, and of suicide in female consultants are of concern, and better preventive measures are needed. The few significant excesses of specific cancers found in certain specialties have no obvious explanation other than chance. A significant excess mortality from cirrhosis in anaesthetists might reflect an occupational hazard and may warrant further investigation.

Risk of testicular cancer in cohort of boys with cryptorchidism

OBJECTIVE

To determine the risk of testicular cancer in relation to undescended testis and its treatment based on recorded details of the maldescent, treatment, and biopsy from case notes.

DESIGN

Cohort study.

SETTING

Hospital for Sick Children, Great Ormond Street, London.

SUBJECTS

1075 boys with cryptorchidism treated by orchidopexy or hormones at the hospital during 1951-64.

MAIN OUTCOME MEASURES

Relative risk of testicular cancer in the cohort compared with men in the general population.

RESULTS

12 testicular cancers occurred in 11 of the patients during follow up to mid-1990 (relative risk of cancer in males with cryptorchidism = 7.5 (95% confidence interval 3.9 to 12.8)). The relative risk fell significantly beyond 15 years after orchidopexy but did not decrease with younger age at orchidopexy. Risk was significantly raised in testes that had had biopsy samples removed during orchidopexy (relative risk = 66.7 (23.9 to 143.3) compared with a testis in a man in the general population) and was significantly greater in these testes than in undescended testes that had not had biopsy samples taken at orchidopexy (6.7 (2.7 to 13.5)). No reasons for biopsy or distinguishing clinical aspects of the testes that had had biopsy samples taken and later developed malignancies were evident in the case notes. No histological abnormalities were evident at initial biopsy except in one testis that had features of dysgenesis.

CONCLUSIONS

Biopsy seems to be a stronger risk factor for testicular cancer than any factor previously identified. The trauma of open biopsy may contribute substantially to risk of malignancy or the testes may have been selected for biopsy on the basis of clinical factors predictive of malignancy but not mentioned in the case notes.

Second malignancy in patients with Hodgkin's disease treated at the Royal Marsden Hospital

Risk of second primary malignancy was assessed in follow-up to June 1991 of 1039 patients first treated for Hodgkin's disease at the Royal Marsden Hospital during 1963-91. A total of 77 second malignancies occurred. There were significantly raised risks of stomach [standardized incidence ratio (SIR)=4.0], lung (SIR=3.8), bone (SIR=26.5), soft tissue (SIR=16.9) and non-melanoma skin (SIR=3.9) cancers, non-Hodgkin's lymphoma (SIR=4.6), and acute and non-lymphocytic leukaemia (SIR=31.3), with a relative risk of 3.3 for all second cancers other than non-melanoma skin cancer. Solid cancer risk was raised to a similar extent in patients treated only with radiotherapy (SIR=2.6, P<0.001), only with chemotherapy (SIR=2.1, P=0.08) and with both (SIR=3.1, P<0.001). Leukaemia risk was raised only in those receiving chemotherapy, whether alone or with radiotherapy. The relative risk for solid cancers was much greater in patients who were younger at first treatment (trend P<0.001), whereas leukaemia risk was greatest for those first treated at ages 25-44. For solid cancers (P<0.001) but not leukaemia (P=0.05) there was a strong gradient of greater relative risks at younger attained ages. The relative risk of second cancers overall was 27.5 at ages under 25 and 2.0 at ages 55 and above. Leukaemia and solid cancer risks in patients treated with chlorambucil, vinblastine, procarbazine and prednisone (ChlVPP) were not significantly greater than those in patients treated with mustine, vincristine, procarbazine and prednisone (MOPP). Number of cycles of chemotherapy was significantly related to risk of leukaemia (P<0.001), and there was a trend in the same direction for solid cancers (P=0.07). The study adds to evidence that alkylating chemotherapy may increase the risk of solid cancers, and that ChlVPP does not provide a less carcinogenic alternative to MOPP chemotherapy. The very large relative risks found for solid cancers at young attained ages and in patients treated when young may have important implications as, in the long term, the majority of second malignancies after Hodgkin's disease are solid cancers. The risks of solid malignancies need clarification by larger collaborative epidemiological studies.

Mortality during 25 years of follow-up of a cohort with diabetes

BACKGROUND

Diabetes is one of the most common chronic diseases in Western populations. There have been few large published cohort studies of people with diabetes that have had more than 10 years of follow-up, and none other than the present one are in the UK. Such studies are important to understand the long-term fatal consequences of diabetes and their variation over time and between countries.

METHODS

Cause-specific mortality was analysed in follow-up from 1966-1970 to December 1992 of 5783 members of the British Diabetic Association living in England and Wales during 1966-1970. Comparison was made with age-, sex- and calendar year-specific mortality by cause in the general population of England and Wales.

RESULTS

During the follow-up 3399 (58.8%) subjects died. The relative risk of all-cause mortality in the cohort compared to the general population was 2.31 in women and 1.58 in men (both P < 0.001).Relative risks were greater for women than men at almost all ages and for each major diabetes-related cause of death. Absolute excess ('attributable') mortality rates were also greater in women than in men, except at ages < 50. Half the deaths in each sex were from circulatory diseases and only 3.4% were from renal disease. The relative risks of mortality for all-causes and circulatory diseases were particularly great at younger ages, but changed little with duration of follow-up. At ages < 40 the relative risks for all-causes were 3.75 in men and 5.51 in women and for ischaemic heart disease were 10.44 and 25.25 respectively (all P < 0.001). At these ages one-third of deaths were due to acute complications of diabetes, suicides and accidents, whereas at older ages these accounted for only 4% of deaths.

CONCLUSIONS

The mortality rates at young ages in the cohort were around twice those in Sweden, Norway and Israel, suggesting that many of the deaths in England and Wales are preventable. The results also indicate a particular need for investigation and amelioration of cardiovascular risk factors in English and Welsh patients, especially women.

Maternal mortality in England and Wales 1970-1985: an analysis by country of birth

OBJECTIVE

To determine the risk of maternal mortality in immigrants to England and Wales.

DESIGN

Analysis of death registrations, 1970-1985, by country of birth.

SETTING

England and Wales.

POPULATION

Women dying in England and Wales during pregnancy, childbirth or the puerperium, or dying from malignant tumour of the placenta.

MAIN OUTCOME MEASURES

The risk of dying in pregnancy, childbirth or the puerperium, adjusted for age and year of death, and the risk of cause-specific death, adjusted for age, in immigrants compared with women born in England and Wales.

RESULTS

Women born in West Africa (relative risk 10.3; 95% CI 8.0-13.2) and the Caribbean (4.6; 3.8-5.7) were at very elevated risk of maternal death and of the main causes of death. Women from Southern Asia (1.6; 1.3-2.0) and "Europe and the USSR' (1.7; 1.2-2.3) were at moderate risk. Adjustment for year of death increased the estimates of risk and women born in the "Rest of the World' and Scotland were at significantly elevated risk.

CONCLUSIONS

An increased incidence of obstetric conditions in immigrant groups may account for the elevated risk but it is also possible that differences in care may account for some of the additional risk. The pattern of increased risk does not appear to be explicable by the parity or social class distribution of immigrants as far as data are available on these. Research is required into the aetiology of the differential incidence of obstetric disease. The collection of routine mortality data which include maternal reproductive and social factors would elucidate the significance of such factors to maternal health. Further investigation into possible differences in the process of antenatal care between immigrants and non-immigrants is required, and into whether this affects the risk of maternal mortality.

A population-based study of cancer risk in twins: relationships to birth order and sexes of the twin pair

One thousand and sixty-three twins with cancer whose co-twin was born alive were identified among patients born since September 1939 with cancers incident in England and Wales during 1971-1984 at childhood and young adult ages. Site-specific risks of cancer were analysed in relation to birth order within the twinship and sexes of the twin pair, using adjusted national birth data to give control distributions of these variables. Risk of leukaemia was increased in first-born twins, risk of testicular cancer was increased in second-born twins with female co-twins but decreased in second-born twins with male co-twins and lung cancer risk was increased in first-born twins with same-sex co-twins. Cutaneous melanoma risk was increased in persons with opposite-sex co-twins, nervous system cancer risk was increased in females with opposite-sex co-twins and Hodgkin's disease risk was increased in persons with same-sex co-twins. For most of the findings, no previous comparable analyses are available, so interpretation of the results must be provisional until the analyses can be repeated on other data. The result for leukaemia would accord with previous suggestions that leukaemia may be of prenatal origin and may sometimes lead to intrauterine death. The Hodgkin's disease result would fit with theories of an infectious aetiology, and this view is strengthened by reanalysis of previous data on paralytic poliomyelitis in twins, which show a pattern similar to that for the Hodgkin's disease patients. Cancer risk in relation to birth order and sex of twins can give novel, objective data relating to prenatal and infectious disease aetiology of cancers.

Naevi and pigmentary characteristics as risk factors for melanoma in a high-risk population: a case-control study in New South Wales, Australia

The relationship between risk of cutaneous malignant melanoma and total body and site-specific naevus counts and other host factors was investigated in a Caucasian population aged 15-84 years in New South Wales, Australia. The study sample comprised 244 cases with melanoma diagnosed in 1989-1993, and 276 controls. The strongest relationship was with total body naevus count. Risk of melanoma was raised 12 times in those with more than 100 naevi compared with those with less than 10. There were also strong risks, with odds ratios of 5 or more, associated with having multiple atypical naevi, multiple large naevi, high naevus counts in sun-exposed or sun-protected areas and being unable to tan on repeated sun exposure. The effect of inability to tan was stronger at younger than older ages. Lesser risks, with odds ratios of 2-3, were associated with being prone to burn on sun exposure, having many freckles as a child and having red hair. The site distribution of naevi in males compared with females resembled the distribution of melanoma by sex. Risk of melanoma of the back was significantly more closely related to back naevus count than naevus count for the remainder of the body. For other anatomical sites, naevus count was non-significantly more closely related to naevus counts at that site than counts over the remainder of the body. Naevus count declined with age in both cases and controls. In those aged under 40, having 100 or more naevi was associated with an aetiological fraction (AF) of 41%. In those aged 60 and over, however, the AF associated with this number of naevi was only 5%.

Fertility, reproductive outcomes, and health of offspring, of patients treated for Hodgkin's disease: an investigation including chromosome examinations

Reproductive outcomes and health of offspring were investigated in 340 patients with Hodgkin's disease first treated at Mount Vernon Hospital, Middlesex, England, at ages under 40 (females) or 45 (males) during 1970-91. Information on offspring was obtained from case-notes and postal questionnaires to the patients. Eleven men and 16 women who had conceived any children after treatment were then interviewed. There was no excess of stillbirths, low birthweight or cogenital malformations, and no cancers have occurred in the 49 offspring after treatment. There was a significant excess of twins, compared with national expectations, in offspring of female patients (RR = 8.52, P = 0.025). Aggregation of series from the literature also showed an excess of twins. Chromosomes from cultures of peripheral lymphocytes from 45 children born to 25 patients (11 men and 14 women) after treatment were examined for numerical abnormalities and for structural abnormalities at the 550 or greater band level of resolution. All were normal except in one child with Down's syndrome (47, XY, +21), for whom we found the origin of the trisomy was from the parent without Hodgkin's disease. The chromosome constitution was also abnormal in one miscarriage (69, XXY; originating from the parent without Hodgkin's disease) and one termination (45, X; for with the parental origin could not be determined) after treatment. The study adds to previous questionnaire data and for the first time provides data also from chromosome analysis, that offspring of patients treated in adulthood for Hodgkin's disease are not at greatly raised risk of genotoxic or other adverse outcomes as a consequence of their parent's treatment. The numbers of offspring assessed in the literature remains small, however, and surveillance of larger numbers of subjects is needed to enable reliable treatment-specific analyses.

Risk of cutaneous melanoma in relation to the numbers, types and sites of naevi: a case-control study

The atypical mole syndrome (AMS) phenotype, characterised by a large number of common naevi as well as atypical naevi, has been described in families with a genetic susceptibility to melanoma. However, the importance of this phenotype for melanoma in the general population has not been conclusively determined. This study was designed to examine the types and distribution of naevi as well as the prevalence of the AMS phenotype in melanoma patients in England compared with controls. A total of 426 cutaneous melanoma cases (61% of all incident cases) aged 16-75 years were recruited between 1989 and 1993 from the north-east Thames region of the UK and 416 controls from the same age group were recruited over the same period and from the same region. Each subject answered a questionnaire covering demographic details, sun exposure history and other risk factors and underwent a skin examination with total body naevus count performed by a dermatologist. The AMS phenotype was defined using a scoring system. Atypical naevi gave the highest relative risk for cutaneous melanoma, with an odds ratio (OR) of 28.7 (P < 0.0001) for four or more atypical naevi compared with none. Many common naevi were also an important risk factor: the OR for 100 or more naevi 2 mm or above in diameter compared with 0-4 naevi was 7.7 (P < 0.0001). Melanoma was also associated with naevi on sun-exposed sites but also with naevi on non-sun-exposed sites such as the dorsum of the feet, buttocks and anterior scalp. Sixteen per cent of the cases had the AMS phenotype compared with 2% of the controls (OR 10.4, P < 0.0001). The AMS phenotype was more common in males than females (P = 0.008). The odds ratio for the presence of the AMS phenotype was dependent on age, with an odds ratio of 16.1 (95% CI 4.6-57.5) for the presence of the AMS phenotype if aged less than 40 compared with an odds ratio of 6.9 (95% CI 2.9-16.6) if aged 40 or more. The AMS phenotype was strongly predictive of an increased risk of melanoma outside the familial context.

Mortality from injuries and other causes in a cohort of 21,800 Brazilian steel workers

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.

Bias caused by migration in case-control studies of prenatal risk factors for childhood and adult diseases

Case-control studies of prenatal risk factors for disease in later life often ascertain cases from within a defined area, trace the birth records of those cases born within the area, and select controls from birth records within the same area. Bias can occur in these studies if the disease risk factors are related to migration from the area. The effects of this bias were examined in a study in Oxfordshire, England. Cases (n = 218) of diabetes in children and young adults born during 1965-1986 were identified from hospital discharges during 1965-1986; controls (n = 753) were selected from livebirths during 1965-1986. By 1987, 219 controls (29.1%) had migrated from Oxfordshire or died. Low maternal parity and high social class were strongly related to migration, more than the other perinatal factors studied. Migration, therefore, could lead to apparent associations of diabetes risk with parity or social class. For a general instance, the authors show how much bias is caused by different degrees of migration and of association between migration and a perinatal risk factor. Examples are given of how migration can produce apparent trends in risk as well as increased or decreased individual relative risks. If more than 25% of controls migrate, bias may be appreciable.

Sex differences in time trends of colorectal cancer in England and Wales: the possible effect of female hormonal factors

Differences between the sexes in time trends of colorectal cancer incidence 1962-87 and mortality 1960-91 in England and Wales are examined in relation to changes in female hormonal factors. There was a trend in the sex ratio of this tumour, particularly marked for the descending colon, whereby the female excess in risk at young ages has almost disappeared but the male excess at older ages has increased. This trend started for cohorts born since the 1920s and coincided with the increase in the use of oral contraceptives and, to a lesser extent, with increases in fertility. The decline has been particularly pronounced for women at young ages born since 1935-39, coinciding with the spread of oral contraceptive use to younger age groups. These results are consistent with the hypothesis that female hormonal factors may play a role in the aetiology of colorectal cancer and with the possibility that oral contraceptive use might exert a protective effect in the descending colon.

Cancer mortality in relatives of women with breast cancer: the OPCS Study. Office of Population Censuses and Surveys

Mortality from cancer and other causes in male and female first-degree relatives of women with breast cancer diagnosed before age 60 has been examined in a large population-based cohort study, providing estimates of familial risks free from ascertainment or recall bias. Relatives of 3,295 patients with breast cancer diagnosed in the UK between 1954 and 1981 were identified through a register of households established in 1939. The 11,678 first-degree relatives thus identified were followed up through national records until the end of 1992. Over this period 5,421 deaths (including 1,527 cancer deaths) occurred in these relatives. Mortality from breast cancer was significantly raised in first-degree relatives (SMR 187, 248 deaths), and there was also significant excess mortality from cancers of the larynx (SMR 177, 17 deaths), endometrium (SMR 166, 29 deaths) and unspecified neoplasms (SMR 153, 70 deaths). The SMR for ovarian cancer was 130, based on 58 deaths (p = 0.06). There was no marked excess for other sites or for non-neoplastic causes of death, but there was a significant deficit in mortality from cervical cancer (SMR 63, 18 deaths). The SMR for breast cancer increased significantly with decreasing age of the relative. After allowing for age, sisters of cases had a slightly (though non-significantly) higher risk than mothers (ratio of SMRs 1.22). These results, together with penetrance estimates from linked families, suggest that approximately one woman in 800 carries BRCAI, the susceptibility gene on chromosome 17q, and that this gene causes about 1% of all breast cancers.

Cancer mortality in relatives of women with ovarian cancer: the OPCS Study. Office of Population Censuses and Surveys

Mortality from cancer and other causes in first-degree relatives of women with ovarian cancer diagnosed before age 60 has been examined in a large population-based cohort study in England and Wales. Relatives of 1,188 ovarian-cancer cases diagnosed between 1954 and 1981 were identified through a register of households established in 1939. Some 4,111 first-degree relatives living in the same household and having the same surname as the index case were followed up through national records until the end of 1992. Over this period, 1,950 deaths (including 574 cancer deaths) occurred in the relatives. Mortality rates within the cohort were compared with age-, sex- and period-adjusted mortality rates for England and Wales. Mortality from ovarian cancer in first-degree relatives was significantly raised (SMR 223, 95% CI 155-310) although the excess was smaller than that found in case-control studies. The SMR increased with decreasing age of the relative, though not with decreasing age of the index case. After allowing for age, sisters of cases had higher ovarian-cancer mortality than mothers (sister:mother SMR ratio 1.89, p = 0.06). The SMR was greater in individuals having 2 first-degree relatives with ovarian cancer (4 deaths versus 0.17 expected, SMR 242). Relatives of ovarian cancer cases also had significantly increased mortality from cancers of the stomach (SMR 146, 69 deaths) and rectum (SMR 150, 33 deaths), and increased mortality from colon cancer, breast cancer and pancreatic cancer which failed to reach statistical significance. Individuals having a relative with colorectal cancer and a relative with ovarian cancer showed a high mortality from both cancers (11 colorectal-cancer deaths versus 1.23 expected, 4 ovarian-cancer deaths versus 0.66 expected.

Cancer mortality in Indian and British ethnic immigrants from the Indian subcontinent to England and Wales

Risk of cancer mortality from 1973 to 1985 in persons born in the Indian subcontinent who migrated to England and Wales was analysed by ethnicity, and compared with cancer mortality in the England and Wales native population, using data from England and Wales death certificates. There were substantial highly significant raised risks in Indian ethnic migrants for cancers of the mouth and pharynx, gall bladder, and liver in each sex, larynx and thyroid in males, and oesophagus in females. There were also substantial raised risks in these migrants of each sex for non-Hodgkin's lymphoma and myeloma. For the mouth and pharynx, and liver in each sex, and gall bladder in females, there were also raised risks of lesser magnitude in British ethnic migrants. For colon and rectal cancer and cutaneous melanoma in each sex, ovarian cancer in women and bladder cancer in men, there were appreciable significantly reduced risks in the Indian ethnic migrants not shared by those of British ethnicity. Appreciable raised risks in British ethnic migrants not shared by those of Indian ethnicity occurred for nasopharyngeal cancer in males, soft tissue malignancy in both sexes and non-melanoma skin cancer in males. In migrants of both ethnicities there were appreciable significantly raised risks in each sex for leukaemia and decreased risks in each sex for gastric cancer, for lung cancer except in females of British ethnicity and in males for testicular cancer. The results suggest the need for public health measures to combat the high risks of oral and pharyngeal cancers and liver cancer in the Indian ethnic immigrant population of England and Wales, by prevention of betel quid chewing and hepatitis transmission respectively. The data also imply that early exposures or early acquired behaviours in India, or exposures during migration, may increase the risk of leukaemia and reduce the risks of gastric and testicular cancers in the migrants irrespective of their ethnicity. Aetiological studies would be worthwhile to investigate the reasons for the sizeable decreased risk of colon and rectal cancer and increased risk of gall bladder cancer in each sex and the increased risk of thyroid and laryngeal cancer in males and oesophageal cancer in females of Indian ethnicity but not of British ethnicity who have migrated from the Indian subcontinent.

Is the apparent rise in cancer mortality in the elderly real? Analysis of changes in certification and coding of cause of death in England and Wales, 1970-1990

The effect of changes in recording and coding of cause of death on trends in cancer mortality in England and Wales in persons aged 45 and over during 1970-1990 is reviewed. During this period, all-cancer mortality rates increased only at ages over 75 in males and over 55 in females. Rises in cancer mortality were largely due to increases in cancer of lung, prostate and unspecified site in men, and of lung, breast and unspecified site in women. Death coding and certification artefacts were much larger in older persons. In those aged 75-84, a change in the position of recording cancer on the death certificate could potentially account for 46% of the recorded increase in prostate-cancer mortality and 28% of the increase in breast-cancer mortality. The decrease in recorded mortality from ill-defined terminal events was far greater than the increase in cancer mortality in this age group. The rise in all-cancer mortality in the elderly was partly due to an increase in lung-cancer mortality, and data artefacts explained a large proportion of the increase in the other common specified cancers in those aged 75-84. The use of routine mortality statistics to chart progress against cancer lacks validity at older ages because of imprecision in certification of cause of death.

Risk of cutaneous melanoma associated with a family history of the disease. The International Melanoma Analysis Group (IMAGE)

In a combined analysis of 2952 melanoma patients and 3618 controls from 8 case-control studies in white populations the risk of cutaneous melanoma was 2.24-fold higher (95% CI, 1.76-2.86) in subjects who reported at least one affected first-degree relative than in subjects who did not. There was no evidence for heterogeneity in the relative risk between the studies, which were from a wide range of latitudes and hence degrees of sun exposure. The effect of family history on melanoma risk was independent of age, naevus count, hair and eye colour, and freckling. There was no evidence for a relationship between family history and primary site of melanoma but there was some suggestion that the familial patients were more likely to have superficial spreading melanoma or lentigo maligna melanoma than acral lentiginous melanoma or nodular melanoma.

Risk of cutaneous melanoma associated with pigmentation characteristics and freckling: systematic overview of 10 case-control studies. The International Melanoma Analysis Group (IMAGE)

Using individual subject data from 10 case-control studies, comprising over 3000 cases and almost 4000 controls, we have estimated the relative risk of melanoma associated with aspects of complexion, namely, hair, eye and skin colour and freckling in adulthood, and have examined the relationships between these factors and naevus count in terms of melanoma risk. Compared with individuals with black or dark brown hair, the relative risks for developing melanoma in those with light brown, blonde and red hair were 1.49 (95% CI 1.31, 1.70), 1.84 (95% CI 1.54, 2.21) and 2.38 (95% CI 1.90, 2.97), respectively. Individuals with blue eyes had a risk 1.55 (95% CI 1.35, 1.78) times that for those with brown eyes, or 1.15 (95% CI 0.94, 1.40) after adjusting for hair colour and freckling in adulthood. The relative risks associated with hair and eye colour were independent of those for naevus count and skin colour. Light skin colour and high freckle density were also highly significant risk factors, independent of each other and of naevus count and hair and eye colour. The risks associated with these factors, while individually modest, are largely independent, and thus pigmentation characteristics and freckling tendency should be useful in identifying high risk groups to be targeted for prevention.

Recent trends in incidence of and mortality from breast, ovarian and endometrial cancers in England and Wales and their relation to changing fertility and oral contraceptive use

Reproductive-related factors play a major role in the aetiology of cancers of the breast, ovary and endometrium. Pregnancy history influences the risk of each of these cancers, and oral contraceptive use modifies the risks of ovarian and endometrial cancers, although its effect on breast cancer risk is less certain. We analysed recent time trends in the incidence and mortality of these cancers in England and Wales and assessed whether they can be explained by changes in fertility and oral contraceptive use. During 1962-87, there were significant increases in the overall incidence of breast cancer (0.95% increase per annum) and ovarian cancer (0.76% per annum) but little increase in endometrial cancer (0.13% per annum). At young ages incidence of each of the cancers has declined in recent years, whereas at older ages there have been substantial increases. Mortality data show similar time trends. In analyses by birth cohort, incidence of each of the cancers increased steeply for successive cohorts born before the turn of the century, and more slowly for cohorts thereafter, reaching a maximum for those born in the 1920s, and decreased for those born subsequently. The increases in incidence for women born before the turn of the century paralleled marked declines in their fertility. The fall in risk for women born after the 1920s was not accompanied by significant increases in their fertility, but coincided with the introduction and increase in use of oral contraceptives. For ovarian and endometrial cancers this accords with strong evidence from person-based studies of the protective effect of oral contraceptives. For breast cancer, the reasons for the recent decline are not clear. It would accord with recent suggestions of a long-term protective effect of oral contraceptives, on which further studies are needed. It is also possible, however, that changes in other risk factors such as dietary fat intake and menarcheal age might have contributed to the recent declines in the risk of these cancers.

Cancer incidence in England and Wales and New Zealand and in migrants between the two countries

Risks of cancer incidence in people born in England and Wales and New Zealand (non-Maoris) living in their home countries, and after migration between the two countries, were analysed using data from their national cancer registries. Since these populations are of similar genetic origin, any real differences in cancer incidence between them are likely to reflect the action of environmental or behavioural risk factors. The greatest differences in risk between the countries were for cutaneous melanoma and lip cancer. In each sex, relative risks of these malignancies were 4 or greater for the New Zealand-born in New Zealand compared with English and Welsh natives in their home country, and risks for migrants in each direction were generally intermediate between those born in the home country in the two countries. Sizeable significantly raised risks in the New Zealand-born in New Zealand compared with English and Welsh natives in England and Wales also occurred for cancers of the mouth, small intestine, colon, thymus, eye and thyroid, and non-Hodgkin's lymphoma in each sex, and for cancer of the prostate. For all of these sites except mouth, small intestine and colon there were also risks around or above New Zealand-born levels for English and Welsh migrants to New Zealand; for colon cancer these migrants had risks close to those in England and Wales. New Zealand migrants to England and Wales had risks of cancers of the colon and prostate that were similar to or above New Zealand levels. Risks of cancers of the stomach, lung, pleura and bladder, and Hodgkin's disease in each sex, and cancers of the cervix, ovary and scrotum and penis, were substantially and significantly lower in the New Zealand-born living in New Zealand than in English and Welsh natives in England and Wales. In English and Welsh migrants to New Zealand risks of bladder cancer in each sex, and of scrotal and penile and pleural cancer in males, approximated to England and Wales risks; cervical cancer risk approximated to the New Zealand risk; and stomach, lung and ovarian cancers showed intermediate risks. Migrants from New Zealand to England and Wales did not gain the lung cancer or clearly the stomach cancer risk of their host country, but did have bladder cancer risks approximating to those in England and Wales.(ABSTRACT TRUNCATED AT 400 WORDS)

Risks of second primary malignancy in patients with cutaneous and ocular melanoma in Denmark, 1943-1989

Risks of 2nd primary cancer were assessed in all patients with cutaneous melanoma (12,460) and all patients with ocular melanoma (2,018) incident in Denmark from 1943 to 1989 and followed for totals of 88,667 person-years and 16,045 person-years, respectively. After cutaneous melanoma, 972 2nd cancers occurred. The risk of non-melanoma skin cancer was significantly raised in each sex. Risk of all non-skin cancers was not raised for all ages but was significantly increased for patients with the primary melanoma incident at ages under 50 years (standardised incidence ratio [SIR], i.e., ratio of observed to expected cancer incidence, multiplied by 100 = 117; 95% confidence interval [CI] 101-134). There were significantly increased risks of chronic lymphocytic leukaemia in males and both sexes combined, brain and nervous system cancers in females and both sexes combined and oropharyngeal cancer in both sexes combined. Risk of pancreatic cancer was not raised, suggesting that cutaneous melanoma patients generally do not share the diathesis for this malignancy which has been observed in certain families with atypical naevi and melanoma. There was no relation of 2nd primary cancer risks to duration since the first primary and no indication of any appreciable treatment-related risk. After ocular melanoma, 216 2nd cancers occurred. There was a significantly increased risk of 2nd cancer overall in males but not females and a significantly increased risk of liver cancer in each sex. Risk of non-melanoma skin cancer (NMSC) was not raised, which suggests that the aetiology of ocular melanoma is not mainly dependent on UV exposure, at least of the type causing NMSC.