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Globally, nitrate levels in source water have increased as a result of agricultural intensification, which has subsequently increased nitrate contamination in drinking water.[sup.1] Recent epidemiological evidence suggests a link between [...]

Objective: To determine whether measurement of cotinine in saliva is a sensitive measure of exposure to second-hand smoke (SHS) among customers in bars. Design: Before/after comparison of saliva cotinine and subjective assessments of SHS. Setting: Three bars in Wellington, New Zealand, June 2003. Participants: Eleven non-smoking medical students spent three hours in each location. They provided saliva samples before and after the visit, counted numbers of lit cigarettes in each bar, and assessed the smokiness of the venue. Samples were tested for cotinine using liquid chromatography coupled with mass spectrometry. Results: Cotinine levels post-visit were consistently higher than baseline. The mean difference was 1.03 ng/mL with a 95% confidence interval of 0.76-1.30 ng/ mL. Adjustments to post-visit levels for metabolism and clearance of cotinine made very little difference to these results. Males tended to have higher baseline levels than females, and to show smaller increases. The bar with the greatest increase in cotinine was judged to be the smokiest on the basis of averaged cigarette counts and scores for presence of smoke and odour. Conclusion: The cotinine in saliva, when tested with the analytic methods described here, provides a means of assessing relatively short-term exposures to SHS.

Background: The New Zealand Census-Mortality Study (NZCMS) aims to investigate socio-economic mortality gradients in New Zealand, by anonymously linking Census and mortality records. Objectives: To describe the record linkage method, and to estimate the magnitude of bias in that linkage by demographic and socio-economic factors. Methods: Anonymous 1991 Census records, and mortality records for decedents aged 0-74 years on Census night and dying in the three-year period 1991-94, were probabilistically linked using Automatch. Bias in the record linkage was determined by comparing the demographic and socio-economic profile of linked mortality records to unlinked mortality records. Results: 31,635 of 41,310 (76.6%) mortality records were linked to one of 3,373,896 Census records. The percentage of mortality records linked to a Census record was lowest for 20-24 year old decedents (49.0%) and highest for 6569 year old decedents (81.0%). By ethnic group, 63.4%, 57.7%, and 78.6% of Maori, Pacific, and decedents of other ethnic groups, respectively, were linked. Controlling for demographic factors, decedents from the most deprived decile of small areas were 8% less likely to be linked than decedents from the least deprived decile, and male decedents from the lowest occupational class were 6% less likely to be linked than decedents from the highest occupational class. Conclusion: The proportion and accuracy of mortality records linked was satisfactorily high. Future estimates of the relative risk of mortality by socio-economic status will be modestly under-estimated by 5-10%.

Objective: To investigate the relationship between the daily number of deaths, weather and ambient air pollution. Method: An ecological study. We assembled daily data for the city of Christchurch, New Zealand (population 300,000) from June 1988 to December 1993. We used Poisson regression models, controlling for season using a parametric method. Results: Above the third quartile (20.5 degrees C) of maximum temperature, an increase of 1oC was associated with a 1% (95% CI: 0.4 to 2.1%) increase in all-cause mortality and a 3% (0.1 to 6.0%) increase in respiratory mortality. An increase in PM(sub 10) of 10 (mu)g/m(super 3) was associated (after a lag of one day) with a 1% (0.5 to 2.2%)increase in all-cause mortality and a 4% (1.5 to 5.9%) increase in respiratory mortality We found no evidence of interaction between the effects of temperature and particulate air pollution. Conclusions: High temperatures and particulate air pollution are independently associated with increased daily mortality in Christchurch. The fact that these results are consistent with those of similar studies in other countries strengthens the argument that the associations are likely to be causal. Implications: These findings contribute to evidence of health consequences of fuel combustion, both in the short term (from local air pollution) and in the long term (from the global climatic effects of increased atmospheric CO(sub 2)).

Objective: To review the epidemiological evidence for the association between passive smoking and lung cancer. Method: Primary studies and meta-analyses examining the relationship between passive smoking and lung cancer were identified through a computerised literature search of Medline and Embase, secondary references, and experts in the field of passive smoking. Primary studies meeting the inclusion criteria were meta-analysed. Results: From 1981 to the end of 1999 there have been 76 primary epidemiological studies of passive smoking and lung cancer, and 20 meta-analyses. There were 43 primary studies that met the inclusion criteria for this meta-analysis; more studies than previous assessments. The pooled relative risk (RR) for never-smoking women exposed to environmental tobacco smoke (ETS) from spouses, compared with unexposed never-smoking women was 1.29 (95% CI 1.17-1.43). Sequential cumulative meta-analysed results for each year from 1981 were calculated: since 1992 the RR has been greater than 1.25. For Western industrialised countries the RR for never-smoking women exposed to ETS compared with unexposed never-smoking women, was 1.21 (95% CI 1.10-1.33). Previously published international spousal meta-analyses have all produced statistically significant RRs greater than 1.17. Conclusions: The abundance of evidence in this paper, and the consistency of findings across domestic and workplace primary studies, dosimetric extrapolations and meta-analyses, clearly indicates that non-smokers exposed to ETS are at increased risk of lung cancer. Implications: The recommended public health policy is for a total ban on smoking in enclosed public places and work sites. (Aust N Z J Public Health 2001; 25:203-11)