Air pollution interventions and respiratory health: a systematic review.

BACKGROUND: Indoor and ambient air pollution exposure is a major risk to respiratory health worldwide, particularly in low- and middle-income countries (LMICs). Interventional trials have mainly focused on alternatives to cooking stoves, with mixed results. Beyond cooking, additional sources of particulate matter also contribute to the burden of air pollution exposure. This review explores evidence from current randomised controlled trials (RCTs) on the clinical effectiveness of interventions to reduce particulate matter in LMICs.METHODS: Twelve databases and the grey literature (e.g., Government reports and policy papers) were searched. Eligible studies were RCTs conducted in LMICs aiming to reduce particulate exposure from any source and reporting on at least one clinical respiratory outcome (respiratory symptoms, lung function or clinical diagnoses). Data from relevant studies were systematically extracted, the risk of bias assessed and narrative synthesis provided.RESULTS: Of the 14 included studies, 12 tested 'improved' cookstoves, most using biomass, but solar and bioethanol cookers were also included. One trial used solar lamps and another was an integrated intervention incorporating behavioural and environmental components for the treatment and prevention of chronic obstructive pulmonary disease. Of the six studies reporting child pneumonia outcomes, none demonstrated significant benefit in intention-to-treat analysis. Ten studies reported respiratory symptom outcomes with some improvements seen, but self-reporting made these outcomes highly vulnerable to bias. Substantial inter-study clinical and methodological heterogeneity precluded calculation of pooled effect estimates.CONCLUSION: Evidence from the RCTs performed to date suggests that individual household-level interventions for air pollution exposure reduction have limited benefits for respiratory health. More comprehensive approaches to air pollution exposure reduction must be developed so their potential health benefits can be assessed.

Exposure reductions associated with introduction of solar lamps to kerosene lamp-using households in Busia County, Kenya.

Solar lamps are a clean and potentially cost-effective alternative to polluting kerosene lamps used by millions of families in developing countries. By how much solar lamps actually reduce exposure to pollutants, however, has not been examined. Twenty households using mainly kerosene for lighting were enrolled through a secondary school in Busia County, Kenya. Personal PM2.5 and CO concentrations were measured on a school pupil and an adult in each household, before and after provision of 3 solar lamps. PM2.5 concentrations were measured in main living areas, pupils' bedrooms, and kitchens. Usage sensors measured use of kerosene and solar lighting devices. Ninety percent of baseline kerosene lamp use was displaced at 1-month follow-up, corresponding to average PM2.5 reductions of 61% and 79% in main living areas and pupils' bedrooms, respectively. Average 48-h exposure to PM2.5 fell from 210 to 104 µg/m3 (-50%) among adults, and from 132 to 35 µg/m3 (-73%) among pupils. Solar lamps displaced most kerosene lamp use in at least the short term. If sustained, this could mitigate health impacts of household air pollution in some contexts. Achieving safe levels of exposure for all family members would likely require also addressing use of solid-fuel stoves.

Chlorinated persistent organic pollutants in serum of New Zealand adults, 2011-2013.

A national survey was conducted in 2011-2013 to assess serum concentrations of persistent organic pollutants (POPs) in adult New Zealanders. Participants were randomly selected from the 2010 Electoral Roll within 64 demographic strata according to 4 age groups, 4 regions, 2 ethnic groups (Maori/non-Maori) and gender. Eligible subjects (n=734) donated up to 30ml of blood, after which serum was pooled (n=49) according to demographic strata prior to analysis by GC-HRMS. Associations between demographic variables (age, region, ethnicity, gender) and serum POPs were assessed using linear regression. The weighted geometric mean (GM) of PCDD/Fs was 5.3pg/g lipid toxic equivalents using the WHO 2005 toxic equivalence factors (TEQ05), which increased by age (3.2, 4.4, 4.8, and 8.1pg/g lipid for the 19-24, 25-34, 35-49, and 50-64year age groups, respectively). The weighted GM of dioxin-like PCBs was 1.4pg TEQ05/g lipid which also increased by age (0.82, 0.86, 1.4, and 2.3pg/g lipid for the same age groups, respectively). Of the detected OCPs, the highest concentration was observed for p,p'-DDE (weighted GM, 220ng/g lipid) followed by hexachlorobenzene (HCB; 7.3ng/g lipid), beta-HCH (7.0ng/g lipid), and dieldrin (4.7ng/g lipid). For most Cl-POPs, concentrations were lowest in the youngest age group, and were similar for men and women and Maori and non-Maori. Serum Cl-POPs were, on average, 50% lower than those measured 15years earlier in 1997. This survey provides evidence of declining serum concentrations of chlorinated POPs in the New Zealand adult population. Age was the most important determinant of POPs concentrations. Body burdens of PCDD/Fs and PCBs in New Zealand are relatively low by international comparison, while for OCPs they are similar or lower compared to those reported for other developed countries.

Household fuels, low birth weight, and neonatal death in India: the separate impacts of biomass, kerosene, and coal.

We examined the impact of maternal use of different household cooking fuels in India on low birth weight (LBW<2500g), and neonatal mortality (death within 28 days of birth). Using cross-sectional data from India's National Family Health Survey (NFHS-3), we separately analyzed the prevalence of these two outcomes in households utilizing three types of high-pollution fuels for cooking - biomass, coal, and kerosene - using low-pollution fuels (gas and biogas) as the comparison "control" group. Taking socioeconomic and child-specific factors into account, we employed logistic regression to examine the impact of fuel use on fetal and infant health. The results indicate that household use of high-pollution fuels is significantly associated with increased odds of LBW and neonatal death. Compared to households using cleaner fuels (in which the mean birth weight is 2901g), the primary use of coal, kerosene, and biomass fuels is associated with significant decreases in mean birth weight (of -110g for coal, -107g for kerosene, and -78g for biomass). Kerosene and biomass fuel use are also associated with increased risk of LBW (p<0.05). Results suggest that increased risk of neonatal death is strongly associated with household use of coal (OR 18.54; 95% CI: 6.31-54.45), and perhaps with kerosene (OR 2.30; 95% CI: 0.95-5.55). Biomass is associated with increased risk of neonatal death among infants born to women with no more than primary education (OR 7.56; 95% CI: 2.40-23.80). These results are consistent with a growing literature showing health impacts of household air pollution from these fuels.

Exposure of hospitality workers to environmental tobacco smoke.

OBJECTIVE: To determine quantitatively the extent of exposure of hospitality workers to environmental tobacco smoke (ETS) exposure during the course of a work shift, and to relate these results to the customer smoking policy of the workplace. SUBJECTS: Three categories of non-smoking workers were recruited: (1) staff from hospitality premises (bars and restaurants) that permitted smoking by customers; (2) staff from smokefree hospitality premises; and (3) government employees in smokefree workplaces. All participants met with a member of the study team before they began work, and again at the end of their shift or work day. At each meeting, participants answered questions from a standardised questionnaire and supplied a saliva sample. MAIN OUTCOME MEASURES: Saliva samples were analysed for cotinine. The difference between the first and second saliva sample cotinine concentrations indicated the degree of exposure to ETS over the course of the work shift. RESULTS: Hospitality workers in premises allowing smoking by customers had significantly greater increases in cotinine than workers in smokefree premises. Workers in hospitality premises with no restrictions on customer smoking were more highly exposed to ETS than workers in premises permitting smoking only in designated areas. CONCLUSIONS: Overall, there was a clear association between within-shift cotinine concentration change and smoking policy. Workers in premises permitting customer smoking reported a higher prevalence of respiratory and irritation symptoms than workers in smokefree workplaces. Concentrations of salivary cotinine found in exposed workers in this study have been associated with substantial involuntary risks for cancer and heart disease.

Is testicular cancer an occupational disease of fire fighters?

BACKGROUND: A previous investigation showed an increased risk of testicular cancer among fire fighters in Wellington City, New Zealand, during the 1980s. Other studies of fire fighters had not identified testicular cancer as an occupational disease. METHODS: This was an historical cohort study of mortality and cancer incidence in all paid New Zealand fire fighters, from 1977 to 1995. RESULTS: The only cancer for which this study provided evidence of an increased risk was testicular cancer, even after excluding cases from the previous investigation. The standardized incidence ratio for 1990-96 was 3.0 (95% confidence interval: 1.3-5.90). There was no evidence that fire fighters were at increased risk from any particular cause of death. CONCLUSIONS: This study confirmed that New Zealand fire fighters are at increased risk of testicular cancer, although the reason is unknown. Other incidence studies of cancer in fire fighters are needed to confirm this finding.

The cost-effectiveness of fluoridating water supplies in New Zealand.

OBJECTIVE: Tooth decay has been substantially reduced in New Zealand, and the difference in caries rates between fluoridated and non-fluoridated areas has narrowed. We investigated whether it is cost-effective to fluoridate water supplies that are now non-fluoridated. METHODS: The net cost of fluoridation was based on the cost of fluoridating a water supply minus the averted costs of treating decay. A range of population sizes was considered. The main analysis was conducted from a societal perspective, using a real discount rate of 5%. Fluoridation was assumed to occur continuously between the years 2000 and 2030. Other assumptions were a Maori population proportion of 15%, no new decay after age 34, and no further dental cost savings after age 45. Information on averted decay in 4 to 12 year old New Zealand children (29,000 receiving fluoridated water and 47,000 receiving non-fluoridated water) was available; information on averted decay in adults was obtained from a study in the United States. Sensitivity analyses investigated the effects of varying the Maori population proportion, the discount rate, and the number of fluoride injection sites. RESULTS: Fluoridation was cost-saving (dental cost savings exceeded fluoridation costs) for communities above about a thousand people. The true break-even community size may be lower. For smaller communities, fluoridation may be considered cost-effective depending on the non-monetised value assigned to an averted decayed surface. CONCLUSIONS AND IMPLICATIONS: Fluoridation remains very cost-effective, and is particularly so for communities with high proportions of children, Maori, or people of low socio-economic status.

Investigation of the prevalence of Legionella species in domestic hot water systems.

AIMS: To investigate the prevalence of Legionella spp. in the hot water systems of a representative sample of Wellington domestic residences with electrically heated hot water systems, and to investigate risk factors (eg water temperature, plumbing materials) for such contamination. METHOD: 100 households with electrically heated hot water systems in the Wellington area were investigated. Samples of hot water from several hot water outlets were collected, and characteristics of the plumbing system were recorded. Water samples and swabs were cultured and further examined by polymerase chain reaction (PCR) and direct fluorescence antibody (DFA) testing to identify Legionella spp. and serogroups. RESULTS: No Legionella spp. were isolated by culture. PCR tested positive for Legionella in specimens from twelve residences. Six of these were also positive by DFA testing. The only environmental factor found to be associated with the presence of Legionella was recent plumbing work on the hot water system. Five of the twelve PCR-positive residences, and four of the six DFA-confirmed residences had hot water delivery temperatures in excess of 60 degrees C. CONCLUSIONS: The results suggest that either Legionellae colonise domestic hot water reticulation systems and/or that the organisms are killed during passage through the hot water tank. Both possibilities may be correct. Further work to characterise the microbial ecology of Legionella-positive hot water distribution systems would be useful, as would the development of improved methods for culturing the organisms from potable water.

Hepatitis B carriage explains the excess rate of hepatocellular carcinoma for Maori, Pacific Island and Asian people compared to Europeans in New Zealand.

BACKGROUND: The aim of this research was to determine the hepatitis B surface antigen (HBsAg) carrier prevalence among cases of hepatocellular carcinoma (HCC), and the population attributable risk of HBsAg carriage for HCC, by ethnicity in New Zealand. METHODS: The hospital notes of HCC cases registered with the New Zealand Cancer Registry, for the years 1987-1994 inclusive, were viewed to determine the HBsAg status. Results The HBsAg status was determined for 193 cases of HCC. The HBsAg carrier prevalence for non-Europeans with HCC was markedly higher than that for Europeans, being 76.7% for Maori, 80.0% for Pacific Island people, and 88.5% for Asians, compared to 6.0% for Europeans. In addition to the effect of ethnicity, HCC cases aged <60 years were more likely to be HBsAg carriers than those aged > or = 60 years. The estimated population attributable risk of HBsAg for HCC, within each ethnic group, was only marginally less than the HBsAg prevalence due to the high relative risk of HBsAg carriage for HCC. The standardized incidence rate ratios of HCC for Maori, Pacific Island people and Asians compared to Europeans were 9.6, 20.4, and 22.3, respectively. Hepatocellular carcinoma attributable to HBsAg carriage explained 79%, 83%, and 92% of the excess standardized rate of HCC, compared to Europeans, for Maori, Pacific Island people, and Asians, respectively. Conclusions The HBsAg carrier prevalence in non-European cases of HCC in New Zealand is between 75% and 90%. HBsAg carriage explains the majority of the excess rate of HCC in non-Europeans compared to Europeans in New Zealand.

Cancer incidence, morbidity and geothermal air pollution in Rotorua, New Zealand.

BACKGROUND: The New Zealand city of Rotorua sits on a geothermal field. However, little is known about the possible health impacts of the geothermal emissions. This was an ecological study that examined cancer incidence and morbidity data for Rotorua. METHODS: Cancer registry and hospital discharge (morbidity) data were obtained for the decade 1981-1990. Standardized incidence ratios (SIR) were calculated comparing Rotorua residents with those living in the rest of New Zealand. Diagnostic categories examined were based on known target organ systems of hydrogen sulphide toxicity. RESULTS: Of the cancer sites, there was an elevated rate for nasal cancers. However, this was based on only four cases. The SIR for cancers of the trachea, bronchus and lung in Maori women was 1.48 (95% CI: 1.03-2.06). This was not explained by higher smoking rates. In the hospital discharge data, a number of diseases showed elevated SIR, notably diseases of the nervous system and the eye. To some extent, these effects were characteristic of effects induced by hydrogen sulphide and also mercury compounds. However, there were few data with which to assess whether significant mercury exposures had occurred, and other explanations were possible. CONCLUSIONS: There are inadequate exposure data for Rotorua to permit conclusions on likely causal associations. However, some of the elevated disease rates were at least consistent with what one might expect to find if sufficient exposures to hydrogen sulphide and/or mercury were occurring.

Acute gastroenteritis diagnostic practices of New Zealand general practitioners.

AIMS: A sample of New Zealand general practitioners was surveyed to determine the laboratory referral practices of general practitioners for patients with acute gastroenteritis, with particular reference to viral gastroenteritis. METHODS: A mail questionnaire was sent to 209 general practitioners throughout New Zealand. RESULTS: The most important criteria for laboratory referral of a diarrhoeal specimen were prolonged duration of illness, presence of blood in the stool, a recent history of overseas travel, tramping or camping, shellfish consumption, or if the patient worked in the food, child care, or health care industries. Most general practitioners reported that they would refer diarrhoeal specimens from less than 25% of their patients with acute gastroenteritis. Requests for testing for viruses other than rotavirus were rare. CONCLUSION: The viral agents causing acute gastroenteritis were less likely to receive laboratory confirmation than other causes of gastroenteritis. On the basis of current laboratory investigation practices of general practitioners, foodborne viral gastroenteritis outbreaks are unlikely to be identified as such in New Zealand.

Old paint removal and blood lead levels in children.

AIM: To identify risk factors, particularly paint removal and clean up practices, for elevated blood lead levels in children, 12 to 24 months old, living in Wellington city. METHODS: Children living in residences more than 50 years old, where residential paint removal had taken place in the last two years, were recruited. Care givers were interviewed, a blood sample was taken from the child's arm and a dust wipe sample was collected from the kitchen floor. Blood and dust samples were analysed for lead content. RESULTS: Data were collected for 141 children (75% of those eligible). The mean blood lead level was 0.24 mumol/L (5.06 micrograms/dL). Higher blood levels were associated with lower income of the main family earner, playing outside, eating dirt and parental hobbies involving lead use. Children receiving regular medical treatment were at lower risk of lead absorption. With the exception of paint removal involving blow torches, none of the paint removal, clean up, or disposal practices was more strongly associated than the other methods with elevated blood lead levels in children living in the household. Dust wipes from the kitchen floor had little predictive value for blood lead level. CONCLUSIONS: High temperature methods of paint removal and parental hobbies involving lead are associated with higher lead levels in children. Given the availability of alternative means of paint removal, continuing use of high temperature methods is unnecessary. Further work is needed to assess lead absorption risks associated with hobbies involving lead.

Air pollution and mortality in the Rotorua geothermal area.

The effects on human health of geothermal emissions in the Rotorua area have been little studied. We calculated standardised mortality ratios (SMRs), comparing residents domiciled in the Rotorua territorial local authority area with those living in the rest of New Zealand, using mortality data for the decade 1981-1990. The SMRs were adjusted for age, calendar year, sex, and ethnicity. Diagnostic categories examined were based on known target-organ systems of hydrogen sulphide toxicity. Mortality causes examined were diseases of the nervous system and sense organs, diseases of the circulatory system, diseases of the respiratory system, and birth defects. Of these, notably elevated SMRs were found only for diseases of the respiratory system, particularly in Maori women (SMR = 1.61, 95 per cent confidence interval 1.19 to 2.12). A major concern was the possibility of confounding by ethnicity. This is because ethnicity in census data is based on self-identification, whereas ethnicity on death certificates is often based on funeral directors' impressions. This leads to serious underreporting of Maori mortality statistics. For the purposes of this study, this situation was further complicated by indications that ethnicity recording for Maori may be more accurate in the Rotorua area than in the rest of New Zealand. Our analysis suggested that, in general, SMRs based on ethnicity are likely to be spuriously high. Although this study found no clear indications of excess mortality in the Rotorua area likely to have been associated with geothermal emissions, there were limitations in the data that could have prevented the recognition of causal associations.

Testicular cancer in fire fighters: a cluster investigation.

AIM: To investigate an apparent cluster of four testicular cancer cases in Wellington fire fighters with a view to determining whether there was a common causal factor, and whether the cluster was indicative of an occupational risk for fire fighters generally. METHOD: Subjects were interviewed about possible risk factors and occupational histories using a structured questionnaire; medical records were reviewed, and diagnoses were verified from the original histological slides. Data on testicular cancer in fire fighters were obtained from the New Zealand cancer registry. Standardised incidence ratios were calculated to assess the likelihood that the cluster had arisen by chance. RESULTS: All four cancers were verified as germ cell testicular cancers. No common risk factors were apparent from the review of the medical records or from the questionnaire interviews. The only testicular cancers known to have occurred in Wellington fire fighters in the 1980s were the four investigated in this study. Only two of the four cases investigated were registered with the New Zealand cancer registry. The relative risk estimate for Wellington fire fighters for the period 1980-91 was 8.2, with an approximate 95% confidence interval of 2.2-21 (p = 0.002). CONCLUSION: There was an unusually high risk of testicular cancer in Wellington fire fighters in the 1980s, with no obvious explanations, although chance could not be excluded. Whether this high risk continues in the 1990s would require a separate investigation. At present the weight of evidence does not indicate that fire fighters in other areas of New Zealand also experienced an elevated testicular cancer incidence rate.

Case-control study of bladder cancer and arsenic in drinking water.

Mortality from several cancers, including bladder cancer, is elevated in a Taiwanese population exposed to high levels of arsenic in drinking water. Data from the Utah respondents to the National Bladder Cancer Study conducted in 1978 were used to evaluate these associations in a US population exposed to measurable, but much lower, levels of drinking water arsenic. Two indices of cumulative arsenic exposure were used, one representing total cumulative exposure (index 1) and the other, intake concentration (index 2). Overall, there was no association of bladder cancer with either measure; however, among smokers, but not among nonsmokers, positive trends in risk were found for exposures estimated for decade-long time periods, especially in the 30- to 39-year period prior to diagnosis. Exposures were in the range 0.5-160 micrograms/liter (mean, 5.0 micrograms/liter). The data raise the possibility that smoking potentiates the effect of arsenic on risk of bladder cancer. However, the risk estimates obtained are much higher than predicted on the basis of the results of the Taiwanese studies, raising concerns about bias or the role of chance. Confirmatory studies are needed.

Chlorinated organic contaminants in breast milk of New Zealand women.

Breast milk samples from 38 women in New Zealand were analyzed for organochlorine pesticides, polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) as part of a World Health Organization collaborative study of breast-milk contaminants. The women were recruited from two urban areas (Auckland and Christchurch) and two rural areas (Northland and North Canterbury) in the North and South Islands of New Zealand. The best predictor of contaminant concentrations in breast milk was found to be the age of the mother. Regional differences were found for hexachlorobenzene, dieldrin, and pp-DDE, reflecting historical use patterns. Urban-rural differences were found for several PCBs, PCDDs, and PCDFs when contaminant concentrations were calculated on a whole-milk basis. However, these differences could be attributed to variation in breast-milk fat concentrations between urban and rural mothers. Urban mothers had about 50% more breast-milk fat than rural mothers. Evidence suggests that breast-milk consumption by babies is regulated by caloric intake. Almost all of the caloric content of milk is in the fat fraction. This suggests that breast-milk contaminant levels calculated on a whole-milk basis do not necessarily reflect the relative levels of exposure of infants to these contaminants. However, the factors that influence breast-milk fat concentration deserve further study.

Confidence limit analyses should replace power calculations in the interpretation of epidemiologic studies.

Frequently, after an epidemiologic study is completed, statistical power to detect a relative risk of interest is recalculated using data obtained during the course of the study. A negative study may then be dismissed on the grounds that its power was too low. However, post hoc power calculations ignore the actual relative estimate and its variance, which are by then known. We present evidence that post-study power calculations have little value and should be replaced by a more informative method using the upper (1 - alpha)% confidence limit of the point estimate that touches the value of the relative risk of interest.

Cancer risks from arsenic in drinking water.

Ingestion of arsenic, both from water supplies and medicinal preparations, is known to cause skin cancer. The evidence assessed here indicates that arsenic can also cause liver, lung, kidney, and bladder cancer and that the population cancer risks due to arsenic in U.S. water supplies may be comparable to those from environmental tobacco smoke and radon in homes. Large population studies in an area of Taiwan with high arsenic levels in well water (170-800 micrograms/L) were used to establish dose-response relationships between cancer risks and the concentration of inorganic arsenic naturally present in water supplies. It was estimated that at the current EPA standard of 50 micrograms/L, the lifetime risk of dying from cancer of the liver, lung, kidney, or bladder from drinking 1 L/day of water could be as high as 13 per 1000 persons. It has been estimated that more than 350,000 people in the United States may be supplied with water containing more than 50 micrograms/L arsenic, and more than 2.5 million people may be supplied with water with levels above 25 micrograms/L. For average arsenic levels and water consumption patterns in the United States, the risk estimate was around 1/1000. Although further research is needed to validate these findings, measures to reduce arsenic levels in water supplies should be considered.