Risk factors for aboriginal low birthweight, intrauterine growth retardation and preterm birth in the Darwin Health Region

Risk factors for Aboriginal low birthweight (< 2500 g), preterm birth (< 37 weeks' gestation) and intrauterine growth retardation (under the tenth percentile of Australian birthweights for gestational age) were examined in 503 live-born singletons recorded as born to an Aboriginal mother and routinely delivered at the Royal Darwin Hospital between January 1987 and March 1990. Infants born to mothers with body mass index less than 18.5 kg/m2 had five times the risk of having low birthweight and 2.5 times the risk of intrauterine growth retardation. Population-attributable risk percentages suggest that 28 per cent of low birthweight and 15 per cent of growth retardation could be attributed to maternal malnutrition. Risk percentages for maternal smoking of more than half a packet of cigarettes a day were 18 per cent for low birthweight and 10 per cent for growth retardation. For growth retardation, 18 per cent could be attributed to a maternal age under 20 years. Risk factors for preterm birth were predominantly obstetric: the population-attributable risk percentage for pregnancy-induced hypertension was 26 per cent and for other obstetric conditions was 16 per cent. For Aboriginal births in the Darwin Health Region, maternal malnutrition and smoking are key elements in the prevention of low birthweight and intrauterine growth retardation. Teenage pregnancy is an important risk for intrauterine growth retardation, and pregnancy-induced hypertension is a risk for preterm birth.     

Increasing incidence of carcinoma of the gastric cardia in Sweden from 1970 to 1985

Several American, Japanese and European centres have reported an increase in carcinoma of the gastric cardia, contrary to the general trend in the incidence of gastric cancer. The aim of this nationwide population-based study was to describe trends in the incidence of tumours of the gastric cardia in Sweden over the 16-year period from 1970 to 1985. The Swedish cancer register, which is more than 95 per cent complete, was used to identify cases. There were 1514 men and 481 women with cancer of the gastric cardia. The age-standardized rates increased in men from 1.9 per 10(5) population in 1970-1973 to 3.0 per 10(5) in 1982-1985, corresponding to a mean annual increase of 2.5 per cent (95 per cent confidence interval (c.i.) 1.6-3.4 per cent). In women, the age-standardized rates increased from 0.5 per 10(5) in 1970-1973 to 0.8 per 10(5) in 1982-1985, the mean annual increase being 0.9 per cent (95 per cent c.i. 0.0-1.8 per cent). The highest incidences were found in southern Sweden, contrary to the geographical distribution of gastric cancer in general, which shows a south-to-north gradient. The disparate epidemiological features of cancer of the cardia and gastric cancer at other sites suggest that the aetiologies may also be different. Since little is known about the aetiology of cancer of the cardia, and the incidence seems to be rising rapidly, analytical studies are urgently needed.     

A model for the effect of cigarette smoking on lung cancer incidence in Connecticut

Population based data on smoking history derived from NCHS surveys were used to develop a model for lung cancer incidence in Connecticut. Trends in smoking prevalence suggest that, while the prevalence in men increased earlier than women, more male smokers have quit than their female counterparts. These trends in smoking prevalence suggest striking gender differences in a period effect for the smoking prevalence. Estimates of the proportion of current smokers, ex-smokers, and the mean duration of smoking were used in a model for the lung cancer incidence rates. The form for the relationship between smoking history and the incidence rate for these subgroups was based on information from cohort studies. The models represented a mixture of the smoking subgroups where the effect of smoking was considered to be either a multiplicative effect on the underlying age distribution, or a separate effect in which the level of exposure was the sole contribution to risk among smokers. The multiplicative model explained more than 80 per cent of the deviance for the period and cohort effects, while the non-multiplicative model could only account for trends in females. Hence, these results suggest that a sizeable portion of the period and cohort contributions to the lung cancer incidence trends in Connecticut can be attributed to the multiplicative model that utilizes this smoking information, although the lack of more detailed information is a limiting factor in developing the model.     

Cancers related to tobacco smoking

Tobacco smoking is the major cause of lung cancer. Cigarette smokers have a risk of lung cancer 10 to 15 times greater than nonsmokers. Tobacco and alcohol are the main risk factors for cancers of oral cavity, larynx, pharynx and oesophagus (cancers of the upper respiratory and upper digestive tract) and the effects of tobacco and alcohol are multiplicative. For these cancers, the risk associated with tobacco was about 2 to 4 among people who drink little or no alcohol. Risks of lung cancer and of cancers of the upper respiratory and upper digestive tract increase with an increasing number of cigarettes smoked per day and duration of smoking. Tobacco is also a risk factor for bladder cancer. Cigarette smoking is a possible contributory factor in the development of kidney, pancreatic and cervical cancers. Among males, lung cancer mortality increased regularly over time and today, lung cancer is the leading cause of death and illness from cancer. Substantial reductions in the number of deaths from tobacco-related cancers could be achieved if a large proportion of smokers stopped smoking.     

Acquired urinary incontinence in bitches: its incidence and relationship to neutering practices

A five-year cohort study was conducted on bitches chosen by a sample of 233 randomly selected practising veterinary surgeons in the UK, to estimate the incidence of acquired urinary incontinence (AUI) in neutered and entire animals, and to investigate possible risk factors associated with neutering practices. Information was collected using questionnaires, and data on 809 bitches, of which 22 developed AUI, were obtained. The estimated incidence rates in neutered and entire animals were 0.0174 and 0.0022 per animal-year, respectively (95 per cent confidence intervals: 0.0110, 0.0275 and 0.0009, 0.0058, respectively). The relative risk, neutered vs entire, was 7.8 (95 per cent confidence interval: 2.6, 31.5). The attributable proportion(exposed) and population attributable proportion were 87.1 per cent and 63.1 per cent (95 per cent confidence intervals: 61.9 per cent, 95.6 per cent, and 28.3 percent, 88.5 per cent, respectively). An increased risk, significant at the conventional 5 per cent level, was not demonstrated in animals neutered before, vs after, first heat (relative risk: 3.9, 95 per cent confidence interval: 0.8, 10.4), although the result was significant at the 10 per cent level. Removal of the cervix was not shown to be a risk factor in neutered dogs.     

Chromosomal variability in the genus Nycticebus

The outcome of pregnancy was studied in 148 women over a two year period in a rural area of Kenya as part of a prospective longitudinal study whose main objective was to study the functional effects of mild to moderate malnutrition. Data were collected on maternal anthropometric variables monthly, haemoglobin levels were determined by blood samples taken every six months, food intake was based on two days each month of actual weight and recall. Each woman's past reproductive history was established at the beginning of the study. Birth weight was taken and recorded within seventy two hours of delivery. Discriminant analysis was used to identify predictors of low birthweight. The analysis was based on 123 cases who had complete data on all the variables used in the equation. Of those included in the analysis, 14 women (11%) delivered low birthweight babies and 109 had normal birthweight babies. Results of the discriminant analysis showed that mid upper arm circumference (MUAC), body mass index (BMI), Blood haemoglobin levels (HB) and socioeconomic status (SES), are the best predictors of low birthweight. Ranked in order of relative contribution to birthweight they are BMI, HB, MUAC and SES. Low birthweight prevalence was determined as being 11.2 per cent. Eighty per cent of all known cases were correctly classified using the four variables. As a screening tool for low birthweight this model with four variables has 93% sensitivity, 78.4% specificity, 35.13% positive predictive value and 98.98% negative predictive value. The results suggest that it is possible to identify women at high risk for delivering low birthweight babies at the community level.     

Risk-adjusted cancer-incidence rates (United States)

A risk-adjusted method is proposed for estimating cancer incidence rates from data collected by the Surveillance, Epidemiology, and End Results (SEER) program of the US National Cancer Institute. Unlike the conventional incidence-rate estimates reported by SEER, this method considers only the first primary cancer, and adjusts for population-based cancer prevalence, as well as for surgical procedures which remove an individual from risk of developing a given cancer. Thus, risk-adjusted incidence-rates more accurately reflect the average cancer risk for individuals in the cancer-free, at-risk population. The results of the analysis indicate that, in general, incidence-rate estimates are fairly similar between the conventional and risk-adjusted methods. However, this is not the case for certain cancer sites which may have: (i) a high number of subsequent primary cancers (e.g., melanomas-skin); (ii) a high cancer prevalence proportion (e.g., prostate cancer); (iii) a high number of subsequent primary cancers and prevalence proportion (e.g., female breast); or (iv) a high prevalence of removal of the organ in question (e.g., cervical and uterine cancers). For example, by applying the risk-adjusted incidence method for in situ and invasive cervical cancer, we found that in the period 1990-92 the age-adjusted incidence-rate estimate increased from 57.8 to 66.3 (15 percent) per 100,000 person-years; the greatest increase in the incidence-rate estimate occurred for women aged 65 to 69 years, from 40.1 to 63.2 (58 percent) per 100,000 person-years; and the lifetime risk of developing cervical cancer increased from 4.6 (1 in 22) to 5.5 (1 in 18) percent.     

Variations with time and age in the risks of solid cancer incidence after radiation exposure in childhood

The Japanese atomic bomb survivor incidence data set and data on five other groups exposed to ionizing radiation in childhood are analysed and evidence found for a reduction in the radiation-induced relative risk of cancers other than leukaemia with increasing time since exposure. Overall, reductions of 5.7-6.1 per cent per year of time since exposure are indicated, depending on the time at which the reduction is presumed to start, and all the reductions are statistically significant at the 5 per cent level. There is no significant heterogeneity in the speed of the reductions in relative risk with time by cohort, by cancer type, sex, or age at exposure group. There is a significant reduction of relative risk with increasing age at exposure, but adjustment for age at exposure does not markedly affect the time trends of relative risk. For all of the groups considered, there is a statistically significant increase in the excess absolute risk with increasing time since exposure. However, by contrast with the relative homogeneity of the time trends of relative risk, there is statistically significant heterogeneity by cancer type within the Japanese cohort (P = 0.05) and between the cohorts (P < 0.0001) in the speed of increase of the excess absolute risk with time since exposure.     

Hypertension and long-term cancer incidence and mortality among Swedish men

OBJECTIVE: To examine incidence of cancer and cancer mortality in relation to high blood pressure. DESIGN: A longitudinal study of middle-aged men from a random population sample. SETTING: G?teborg, Sweden. SUBJECTS: We studied 7396 men aged 47-55 years without diagnosed cancer at baseline (1970-1973). MAIN OUTCOME MEASURES: Incidence of cancer and mortality from cancer. RESULTS: By the end of December 1992, 1401 men had been diagnosed with cancer at any site and 651 had died from cancer. Of the men in the highest fifth of the systolic blood pressure distribution (above 166 mmHg) 126 per 10000 observation years were diagnosed with cancer at any site, compared with 91 per 10000 in the lowest fifth [below 130 mmHg; relative risk after adjustment for age, smoking, body mass index, treatment for hypertension and leisure time physical activity 1.41 (95% confidence interval 1.19-1.68); P for trend 0.0001]. Of men in the highest fifth, 55 per 10000 observation years died from cancer, compared with 42 in the lowest [adjusted relative risk 1.41 (1.09-1.82); P for trend 0.01]. Several types of tumour tended to be more common among men with hypertension, but only genito-urinary cancers [age-adjusted relative risk 1.39 (1.04-1.85)] and non-melanoma skin cancer [age-adjusted relative risk 1.98 (1.12-3.51)] were significantly so. Findings were similar for diastolic blood pressure and if data for the first 5 years of follow-up were excluded. There was an increase in risk of cancer also during the first 5 years [adjusted relative risk 1.80 (1.10-2.92) for systolic blood pressure and 1.77 (1.05-2.99) for diastolic blood pressure]. CONCLUSIONS: We found an excess risk of cancer and of death from cancer for men with high blood pressure. Although the increase in risk was comparatively modest, the findings are of public health importance, insofar as both hypertension and cancer are common conditions.     

Local low-dose interleukin-2 induces systemic immunity when combined with radiotherapy of cancer. A pre-clinical study

OBJECTIVES: This study examined whether the decline in birth-weight with increasing altitude is due to an independent effect of altitude or an exacerbation of other risk factors. METHODS: Maternal, paternal, and infant characteristics were obtained from 3836 Colorado birth certificates from 1989 through 1991. Average altitude of residence for each county was determined. RESULTS: None of the characteristics related to birthweight (gestational age, maternal weight gain, parity, smoking, prenatal care visits, hypertension, previous small-for-gestational-age infant, female newborn) interacted with the effect of altitude. Birthweight declined an average of 102 g per 3300 ft (1000 m) elevation when the other characteristics were taken into account, increasing the percentage of low birthweight by 54% from the lowest to the highest elevations in Colorado. CONCLUSIONS: High altitude acts independently from other factors to reduce birthweight and accounts for Colorado's high rate of low birthweight.     

Toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin to several ecological receptor groups: a short review

The objective of this study was to examine the risks for lung cancer associated with lifestyle characteristics of smoking in a developing country where lung cancer is the first cause of mortality by cancer in men, tobacco propaganda is freely allowed, and there are no restrictions operating for smoking. The design was a case-control and hospital-based study. Two hundred men with lung cancer and 397 hospital controls were interviewed. Odds ratio (OR) for current smokers was 8.5, whereas former smokers displayed an OR of 5.3. The risk increased with duration of smoking and with the number of cigarettes smoked per day. The attributable risk for smoking was 85%. Smokers of black tobacco and more than 24 cigarettes/day showed a risk of 12.9 regarding non-smokers, and of 15.5 for 40 or more years duration of smoking. The proportion of cases diagnosed as adenocarcinoma was higher than the proportion of squamous cell carcinoma.     

Solid waste and pancreatic cancer: an ecologic study in Florida, USA

BACKGROUND: Other than cigarette smoking, modifiable risk factors for pancreatic cancer have not been consistently identified. This study explored the ecologic relationship between pancreatic cancer incidence and measures of cigarette smoking, income, and solid waste collection for Florida's 67 counties. METHODS: We used Florida's population-based cancer registry to compare county-specific incidence rates of pancreatic cancer among Whites to median household income, the per county prevalence of cigarette smoking, and to measures of per capita municipal solid waste collected. RESULTS: County-specific incidence rates for pancreatic cancer ranged from 0 to 8.1 per 100,000 per year and were significantly correlated with income (r = 0.35), cigarette smoking (r = 0.39), and solid waste (r = 0.47). The correlation between pancreatic cancer and solid waste was largely attributable to one sub-component of solid waste, yard trash (grass clippings, and tree and shrub trimmings) (r = 0.42). Using a stepwise regression procedure, only cigarette smoking and yard trash remained significant in the model. CONCLUSIONS: These data suggest that some factor associated with grass and tree trimmings, e.g. insecticides and herbicides, may increase the risk for pancreatic cancer. This hypothesis is consistent with several reports of pancreatic cancer and insecticide exposure in individuals and may suggest new avenues for research in pancreatic cancer.     

Lung cancer after radiation therapy for breast cancer

BACKGROUND: Radiation, including radiation therapy (RT) for a variety of conditions, is known to be a lung carcinogen. METHODS: Data from the Surveillance, Epidemiology, and End Results program of the National Cancer Institute for 1973-1986 were utilized to investigate whether RT for breast cancer affects the risk of subsequent lung cancer. The relative risk was calculated by comparing the incidence rate in patients with irradiated breast cancer with that in those with nonirradiated breast cancer. RESULTS: It was found that the risk of lung cancer overall was increased in women who underwent irradiation compared with those who were not irradiated 10 years after the initial breast cancer diagnosis with a relative risk of 2.0 (95% confidence interval, 1.0-4.3). In addition, the risk of lung cancer was in the ipsilateral lung compared with the contralateral lung for irradiated women. This increase was observed after 10 years for lung cancer overall and for the three major histologic subgroups (small cell, squamous cell, and adenocarcinoma). Specific information on RT doses and treatment plans and cigarette smoking were not available. CONCLUSIONS: It was concluded that RT for breast cancer may increase the risk of lung cancer after a latency period of 10 years.     

Age standardized incidence rates of oral cancer in South Africa, 1988-1991

While numbers of papers on oral cancer in South Africa have been published, there have been very few studies on standardized morbidity rates. This paper has developed data collected by the National Cancer Registry from the entire country for the four year period 1988-1991 to present frequency, age standardized incidence rates (ASIRs) and life-time risk (LR) for histologically-diagnosed intra-oral cancers in female and male Asian, black, coloured and white South Africans. During this period 5396 cases of oral cancer were diagnosed in a total number of 157,307 cancer cases (3.4 per cent) excluding squamous cell carcinoma (SCC) and basal cell carcinoma (BSC) of the skin. Intra-oral cancer in all South African females and males accounted, respectively, for 1.8 per cent and 5.0 per cent of all cancers. There was a male preponderance in black, coloured and white groups but females were affected more frequently than men among Asians. The incidence in Asian women (6.66) was higher than those of the women in any of the other population groups, whereas the lowest incidence was found in black women (1.75). The incidence rate in coloured men was particularly high (13.13) whereas the incidence in white males (8.06) was not substantially lower than among black males (9.05). Differences between the eight groups were not significant (X2 = 6.24, df = 3, p > 0.1). The Cumulative Life Time Risk (LR) of developing intra-oral cancer for males and females in the four population groups ranged from 1:65 in coloured males to 1:455 for black females. Gender differences in LR in both black and coloured groups, signals substantial differences in exposure to known carcinogens for this disease. It is disturbing to note that the incidence in the period 1988-1991 was higher in Indian women that it was in 1964-1966, and that educative preventive measures have failed. Similarly, the incidence of intra-oral cancer in coloured men of 13.13 is substantially higher than the figure of 8.8 reported in 1979. If this is an accurately reflected trend, then a major educative programme needs to be pursued in this direction if the relative risk of one in 65 is to be reduced.     

A 21-year experience of abdominal aortic aneurysm operations in Edinburgh

BACKGROUND: This study reviews the results of infrarenal abdominal aortic aneurysm (AAA) surgery over 21 years (1 January 1976 to 31 December 1996). METHODS: A prospectively gathered database was analysed. RESULTS: Infrarenal AAA repair was performed in 1515 patients: 492 (32.5 per cent) had elective repair of an asymptomatic AAA; 194 (12.8 per cent) had elective repair of a symptomatic AAA; 156 (10.3 per cent) had emergency repair of a symptomatic non-ruptured AAA; and 673 (44.4 per cent) had surgery for a ruptured AAA. The 30-day and/or same admission mortality rates were 6.1, 5.8, 14.1 and 37 per cent respectively. Operative mortality increased in all four groups over the study interval, although this only attained statistical significance in patients having elective repair of a symptomatic, non-ruptured AAA. There was a significant increase in the age of patients undergoing elective repair of an asymptomatic AAA, but not in the other three groups. There was also a significant increase in the proportion of straight 'tube' grafts inserted in all four groups. CONCLUSIONS: It remains the minority of patients who have elective operation before the onset of symptoms and/or rupture. Despite anaesthetic and surgical specialization, the results of AAA repair have not improved over the past two decades. Operative mortality may be increasing, possibly because of the increasing age and associated comorbidity of the patients presenting to this unit.     

Is adolescent pregnancy hazardous?

A study of the pregnancy outcome in 3320 teenagers revealed a low incidence of pre-eclampsia and anaemia and high rates of eclampsia, prematurity and low birthweight. The perinatal loss was 2.2 per cent and there was one maternal death. A comprehensive programme designed to improve antenatal surveillance is recommended for adolescents.     

Inflammatory breast cancer and body mass index

PURPOSE: No studies have investigated the etiology of inflammatory breast cancer (IBC), the most lethal form of breast cancer. Because high body mass index (BMI) is associated with decreased risk of premenopausal breast cancer but increased risk of postmenopausal breast cancer, we evaluated whether high BMI was a risk factor for IBC. PATIENTS AND METHODS: In a case-comparison study, we matched by ethnicity and registration date 68 IBC patients treated at The University of Texas M.D. Anderson Cancer Center from 1985 to 1996 with 143 patients with non-IBC and 134 patients with cancer at sites other than the breast or reproductive tract (non-breast cancer). The non-breast cancer group was used in lieu of a population-based, healthy control group, which was not available. RESULTS: IBC patients were younger at menarche and the time of their first live birth than non-IBC and non-breast cancer patients. The proportion of premenopausal IBC patients was higher than the proportion of premenopausal women in the comparison groups, although differences were not significant. There were no differences in height, but IBC patients were heavier (77.6 kg) than non-IBC (70.0 kg) and non-breast cancer patients (68.0 kg). After adjusting for other factors, women in the highest BMI tertile (BMI > 26.65 kg/m2) relative to the lowest tertile (BMI < 22.27) had significantly increased IBC risk (IBC v non-IBC, odds ratio [OR] = 2.45, 95% confidence interval [CI] = 1.05 to 5.73; IBC v non-breast cancer, OR = 4.52, 95% CI = 1.85 to 11.04). This association was not significantly modified by menopausal status and was independent of age at menarche, family history of breast cancer, gravidity, smoking status, and alcohol use. CONCLUSION: Our investigation showed that high BMI was significantly associated with an increased risk of IBC. This association did not vary by menopausal status, although IBC patients were more likely to be premenopausal. Confirming our findings and identifying other IBC risk factors may provide directions for future research on the aggressive nature of IBC.     

cGMP-kinase mediates cGMP- and cAMP-induced Ca2+ desensitization of skinned rat artery

The incidence rate of breast cancer in Japan rose more than two-fold from 1959-60 to 1983-87. To assess to what extent this increase can be explained by changes in the prevalence of four major risk factors of breast cancer (i.e. age at menarche, age at first birth, age at menopause, and parity), we estimated the probability of developing breast cancer based on the joint distribution and relative risks of these four risk factors. The age-specific incidence rate during 1959-60 reported by the Miyagi Prefectural Cancer Registry was used to estimate the baseline hazard rate for women without the four risk factors in the same age group. Assuming that the baseline hazard rate is constant during all periods, we calculated the expected incidence rates during the periods of 1959-60, 1962-64, 1968-71, 1973-77, 1978-81, and 1983-87 for each age group. Large discrepancies were noted between the observed and expected incidence rates during 1983-87 in all age groups. The change in the joint distribution of the four risk factors accounted for less than 40% of the increase observed from 1959-60 to 1983-87, suggesting the effects of other powerful risk factors.     

The surgical therapy of prostatic tumors]

A random sample of 26,000 Swedish women who were asked about their smoking habits in the early 1960s have now been followed for 26 years with respect to cancer incidence. Most findings regarding tobacco smoking and cancer from studies of men were confirmed also among the women. Elevated relative risk for current smokers compared with women who never smoked regularly were seen for cancers of the lung, upper aerodigestive sites, pancreas, bladder, cervix and all cancers combined, as well as a notably high relative risk for cancers of organs of the urinary tract other than kidney and bladder. Relative risk increased with dose, measured as grams of tobacco smoked per day, for cancers of the upper aerodigestive sites, lung, cervix, bladder, organs of the urinary tract other than kidney and bladder and all cancers combined. For cancers of the lung, bladder and cervix, there was an inverse relationship with age when starting to smoke tobacco. The reported inverse relationship between smoking and endometrial cancer could not be corroborated, nor was there any significant relationship between smoking and colorectal or breast cancer.     

Epidemiology of renal cell carcinoma in Connecticut, 1935-1973

Data on over 3,700 patients with renal cell carcinoma, reported to the Connecticut Tumor Registry from 1935 through 1973, were used to assess incidence, survival, and associations of risk with demographic characteristics. Incidence increased over time among men, but not among women; a birth cohort effect suggesting increasing incidence rate over time was demonstrated for men. A comparison of male and female age-specific incidence rates indicated that, in the 15- to 39-year-old age group, men were three times more likely than women to develop the disease; after age 40, renal cell carcinoma was diagnosed in men twice as often as in women. Survival probability has increased from 1940 to the present time. A high density of persons per square mile was associated with a higher-than-expected incidence. No trends in incidence according to socioeconomic status were observed.