Mortality and cancer incidence at a fire training college.

BACKGROUND: An investigation into concerns about possible health effects of fire training practices at an Australian training facility recommended a study to investigate the risk of cancer and mortality of those with risk of chronic occupational exposure to several chemicals. AIMS: To investigate mortality and cancer incidence in firefighters at the Country Fire Authority (CFA) Fiskville training facility, Victoria, Australia, between 1971 and 1999. METHODS: CFA supplied human resources records, supplemented by self-reported information for a retrospective cohort, and allocated firefighters to low, medium or high groups based on probability of exposure. We linked the cohort to state and national cancer and mortality data. We calculated standardized mortality ratios and standardized cancer incidence ratios (SIRs). RESULTS: The high group (n = 95) had a clearly increased risk of overall cancers SIR = 1.85 (95% CI 1.20-2.73), testicular cancer SIR = 11.9 (1.44-42.9) and melanoma SIR = 4.59 (1.68-9.99) relative to the population of Victoria. Brain cancer was significantly increased for the medium group (n = 256): SIR = 5.74 (1.56-14.7). Mortality was significantly reduced for all groups. CONCLUSIONS: Dealing with supplied records can be problematic but despite the small numbers, we identified an increased risk of cancer for the high group. The mortality data suggested that there was under-ascertainment for the medium and low groups which underestimated risk and a possible reporting bias for brain cancer. Small cohorts can still provide statistically significant findings when investigating locations for cancer risk.

A predictive model of the health benefits and cost effectiveness of celiprolol and atenolol in primary prevention of cardiovascular disease in hypertensive patients.

This study compares the antihypertensive and lipid modifying effects of treatment of mild to moderate hypertension with celiprolol or atenolol. It also models the 5-year cardiovascular risk reduction and the cost effectiveness of monotherapy from a partial societal perspective. The effects of celiprolol and atenolol on systolic blood pressure (SBP), total serum cholesterol (TC) and high density lipoprotein cholesterol (HDL-C) were obtained from a pooled analysis of published studies. Although celiprolol and atenolol had similar effects on SBP, celiprolol reduced the ratio of TC to HDL-C by 10.2% [95% confidence intervals (95% CI) -16.4%, -4.0%) but atenolol increased the ratio by 7.7% (95% CI of 3.4%, 12.0%). The 5-year absolute risks of an initial coronary or cerebrovascular event or cardiovascular death were computed for cohorts of patients treated with either agent or remaining untreated, using an accelerated failure time (AFT) model, based on Framingham Heart Study data. Inputs to the model were age, gender, smoking status, SBP, TC and HDL-C. The change in absolute risk was estimated using the changes in SBP and TC: HDL-C obtained from the pooled analysis. Average life-months gained by therapy were computed as differences between the Kaplan-Meier survival curves estimated from the model plus differences in 5-year cardiovascular death rates multiplied by average life expectancy obtained from life tables. Direct medical costs included drug treatment, and the costs of acute care for initial coronary and cerebrovascular events deferred by therapy over the 5-year treatment period. The model shows that in the lowest-risk base case (60-year-old men who are nondiabetic and nonsmokers with SBP of 160 mm Hg and a 5-year absolute cardiovascular risk of 12%), celiprolol (271 mg/day) is 2-fold more effective than atenolol (77.4 mg/day) in reducing coronary event risk, and equally effective in reducing cerebrovascular event risk. The number of individuals that would have to be treated for 5 years to avoid 1 coronary event is about 30 for celiprolol versus 70 for atenolol. Therapy with celiprolol yields more life-months and at current prices, the cost per life-year gained by therapy is significantly lower. Both drugs are cost effective by international standards in the treatment of patients with 5-year absolute cardiovascular risk greater than 10%, and are more cost effective in those patients at higher levels of absolute cardiovascular risk. The direct medical costs of treatment for 5 years with celiprolol are the same or slightly less than treatment with atenolol at the dosages used in the clinical trials, despite a 19% higher tablet price. Both drugs are more cost effective in patients at higher levels of absolute cardiovascular risk. These findings are sensitive to the drug dosages, tablet prices and the discount rate. Based on epidemiological and clinical data, replacing atenolol with celiprolol in patients with mild to moderate hypertension, but without overt cardiovascular disease, is predicted to have similar effects on stroke risk, but to be substantially more effective in reducing the risk of coronary events at no additional direct medical cost over a 5-year treatment period.

Migraine: a risk factor for motor vehicle driver injury?

To test the hypothesis that migraine is associated with motor vehicle driver injury, data collected from 10,529 individuals on personal history of migraine and motor vehicle injury were analysed cross-sectionally. In multiple logistic regression analyses, the adjusted odds ratio for motor vehicle driver injury associated with migraine was 2.3 [95% confidence interval (CI) 1.9-2.7]. After excluding those who also had a history of head injury, the odds ratio was 1.5 (95% CI: 1.2-2.0). These results suggest that migraine may be associated with a 50% increase in the risk of motor vehicle driver injury and that in this population may account for as many as one in every 20 motor vehicle driver injuries. These findings require confirmation in prospective studies of motor vehicle driver injuries.

Socioeconomic distribution of smoking in a population of 10,529 New Zealanders.

AIMS: This study aimed to investigate the associations of several smoking variables with socioeconomic status. METHODS: Cross-sectional analyses of data about smoking behaviour and socioeconomic status (education, occupation and neighbourhood income) were performed using baseline data from the Fletcher Challenge-University of Auckland Heart and Health Study (10,529 participants). RESULTS: After adjustment for age and sex, lower educational level was associated with: (1) higher frequency of ever having smoked (65% of participants who had attended secondary school for fewer than two years, versus 43% of participants who had attended university; 2p < 0.0001); (2) lower likelihood of having quit (46% versus 71%; 2p < 0.0001); (3) higher likelihood of being a current smoker (35% versus 12%; 2p < 0.0001); (4) higher tobacco consumption per smoker (13 manufactured cigarettes/day versus 8 manufactured cigarettes/day; 2p < 0.0001); and (5) higher tobacco consumption per participant (1980 cigarette-equivalents/year versus 450 cigarette-equivalents/year; 2p < 0.0001). Similar, but shallower, associations of these smoking variables were observed with occupation and neighbourhood income (with the exception that tobacco consumption per smoker was not associated with neighbourhood income). The socioeconomic gradients of tobacco consumption per study participant with all three socioeconomic indicators were particularly steep among younger participants, men and Maori. CONCLUSIONS: Participants of low socioeconomic status consumed a disproportionately large amount of tobacco. Policies that prevent smoking initiation and promote smoking cessation in low socioeconomic groups are therefore needed. These should include targeting of mass media messages to low socioeconomic groups, public subsidisation of nicotine replacement therapy and higher taxes on tobacco.

Mortality after hip fracture: regional variations in New Zealand.

AIM: To determine the 35-day and one-year mortality rates following a hospital admission for hip fracture, among individuals aged 60 years or older in New Zealand. METHODS: New Zealand Health Information Service mortality data for the years 1988 to 1992 were examined to determine the case fatality rate among individuals aged 60 years or older admitted to hospital for fractures of the neck of femur (ICD-9 N-code 820). Case fatality rates assessed at 35 days and one year after admission to hospital were examined by age, gender, year of admission, place of residence, area health board region and cause of death. RESULTS: Between 1988 and 1992, the case fatality rate was 8% within 35 days of admission to hospital and 24% within one year of admission. Case fatality rates were found to be twice as high in men compared to women and four to five times higher in individuals aged 85 years and older, compared to people aged between 60 and 64 years. The only regional difference in hip fracture mortality was found in the Canterbury area health board region, which had a 30% higher rate of hip fracture mortality compared to all regions combined. The two main cited underlying causes of death after hip fracture were accidental falls (ICD E880-E888) and ischaemic heart disease (ICD 410-414). CONCLUSION: Over three-quarters of individuals aged 60 years or older who are hospitalised with a hip fracture in New Zealand survive for at least one year after admission. However, significant variations in mortality exist with age and gender. These data highlight the importance of preventive strategies for hip fracture in older people and the need to identify ways of improving post-admission care.

Ethnic differences in blood pressure: findings from the Fletcher Challenge-Auckland University Heart and Health Study.

AIMS: To investigate the determinants of ethnic differences in blood pressure, hypertension and the prevalence of additional risk factors for cardiovascular disease among a New Zealand population. METHODS: Baseline data from the Fletcher Challenge-University of Auckland Heart and Health Study were analysed for ethnic differences in blood pressure, and the likelihood of those with hypertension having other major cardiovascular disease risk factors was estimated. RESULTS: Maori and Pacific Islands participants had mean diastolic blood pressure up to 3 mmHg higher than Europeans, but Pacific Islands people had mean systolic blood pressure 3-4 mmHg lower than Europeans and Maori respectively. After adjustment for age and gender almost 20% of Maori, 16% of Pacific Islands and 11% of European people were classified as hypertensive. Adjustment for body mass index and alcohol consumption almost eliminated ethnic differences in blood pressure, and body mass index was found to be the single most important modifiable determinant of raised blood pressure. Greater proportions of Maori (15%) and Pacific Islands people (14%) with hypertension had multiple additional cardiovascular risk factors compared with Europeans (8%), but similar proportions were on antihypertensive drug treatment. CONCLUSIONS: Efforts to reduce obesity have the potential to significantly reduce raised blood pressure among Maori and Pacific Islands people. Overall cardiovascular risk is more likely to be higher in Maori and Pacific Islands people than in Europeans with hypertension, indicating that greater proportions of Maori and Pacific Islands people with high blood pressure should be receiving treatment.

Fletcher Challenge-University of Auckland Heart & Health Study: design and baseline findings.

AIMS: The aims of this prospective observational study are to determine the relationship of sociodemographic factors, psychological factors and several factors measured in blood, with the risk of coronary heart disease (CHD) in a New Zealand population. METHODS: Participants were recruited from two sources: employees of the Fletcher Challenge Group and individuals listed on the general electoral roll for the Auckland region. Baseline and follow up risk factor data were obtained from a questionnaire, blood samples and a simple physical examination. Outcome data on deaths and hospitalisations due to coronary heart disease will be obtained primarily through linkage of participant identifiers to data collected nationally by the New Zealand Health Information Service. RESULTS: A total of 10,529 individuals agreed to participate (8011 from Fletcher Challenge and 2518 from the electoral roll), representing a response rate of 74%. Within the study population, there was a broad distribution of sociodemographic characteristics including ethnicity-10% of participants were Maori and 5% were of Pacific Islands origin. There was also wide heterogeneity of coronary heart disease risk as judged from the distributions of established risk factors at baseline-5% of participants had evidence of existing coronary heart disease, a quarter were current smokers, a sixth were nondrinkers, almost a half were overweight, a fifth had blood pressure > or = 150/95 mmHg or were receiving antihypertensive treatment and a sixth had cholesterol levels > or = 6.5 mmol/L. CONCLUSIONS: This is the first, large scale prospective observational study of the determinants of coronary heart disease in a New Zealand population. The study participants represent a broad cross section of society, with wide variation in sociodemographic characteristics and coronary heart disease risk. Initial results concerning the relationships of primary interest should be available within 5 years when sufficient coronary heart disease events have been documented to allow reliable analyses.

Association of environmental tobacco smoke exposure with socioeconomic status in a population of 7725 New Zealanders.

OBJECTIVE: To test the hypothesis that environmental tobacco smoke (ETS) exposure is inversely associated with socioeconomic status. DESIGN: Survey. SETTING: General community, New Zealand. PARTICIPANTS: 7725 non-smoking adults (volunteer sample of a multi-industry workforce, n = 5564; and a random sample of urban electoral rolls, n = 2161), including 5408 males; mean age 45 years. MAIN OUTCOME MEASURES: ETS exposure was assessed as self-reported number of hours per week spent near someone who is smoking, and as prevalence of regular exposure to some ETS. Socioeconomic status was assessed as educational level, occupational status, and median neighbourhood household income. RESULTS: Both measures of ETS exposure were steeply and inversely associated with all three indicators of socioeconomic status (all p < 0.0001). Geometric mean ETS exposure ranged from 16 minutes per week among university-educated participants to 59 minutes per week in the second lowest occupational quintile (95% confidence intervals: 14-18 minutes per week and 54-66 minutes per week). The associations with occupational status and educational level were steeper than those with neighbourhood income. The socioeconomic gradients of ETS exposure were steeper among participants aged less than 35 years than among participants aged over 50 years, among men than women, and among Maori than Europeans. CONCLUSIONS: In this study population, ETS exposure was inversely associated with socioeconomic status. Greater ETS exposure might therefore contribute to the higher risks of disease and death among low socioeconomic groups. These results provide a further rationale for targeting tobacco control measures to people in low socioeconomic groups.

Random errors in the measurement of 10 cardiovascular risk factors.

Random errors in the measurement of 10 commonly investigated cardiovascular risk factors (systolic and diastolic blood pressure, blood cholesterol, blood glucose, pulse rate, body mass index (BMI), cigarette consumption, passive smoking, alcohol intake and physical exercise) were assessed in a general population cohort (n = 2517) and a workforce cohort (n = 8008). Random errors were estimated from regression dilution ratios (lower ratios imply greater random error, and a ratio of one implies no random error). All of the risk factors, except for BMI (which had regression dilution ratios of 0.93 and 0.98 in the two cohorts), were measured with substantial levels of random error. Particularly low regression dilution ratios were observed for physical exercise (0.28 and 0.39) and pulse rate (0.47 and 0.56). For each of these risk factors, with the possible exception of BMI, associations with long-term average values could be importantly biased toward the null unless appropriate corrections are made.