Evan Dryson

Case-control study of high risk occupations for bladder cancer in New Zealand

We conducted a nationwide case‐control study of bladder cancer in adult New Zealanders to identify occupations that may contribute to the risk of bladder cancer in the New Zealand population. A total of 213 incident cases of bladder cancer (age 25–70 years) notified to the New Zealand Cancer Registry during 2003 and 2004, and 471 population controls, were interviewed face‐to‐face. The questionnaire collected demographic information and a full occupational history. The relative risks for bladder cancer associated with ever being employed in particular occupations and industries were calculated by unconditional logistic regression adjusting for age, sex, smoking and socio‐economic status. Estimates were subsequently semi‐Bayes adjusted to account for the large number of occupations and industries being considered. An elevated bladder cancer risk was observed for hairdressers (odds ratio (OR) 9.15 95% Confidence Interval (95%CI) 1.60–62.22), and sewing machinists (OR 3.07 95%CI 1.35–6.96). Significantly increased risks were not observed for several other occupations that have been reported in previous studies, including sales assistants (OR 1.03 95%CI 0.64–1.67), painters and paperhangers (OR 1.42 95%CI 0.56–3.60), sheet metal workers (OR 0.39, 95%CI 0.15–1.00), printing trades workers (OR 1.11 95%CI 0.41–3.05) and truck drivers (OR 1.36 95%CI 0.60–3.09), although the elevated odds ratios for painters, printers and truck drivers are consistent with excesses observed in other studies. Nonsignificantly increased risks were observed for tailors and dressmakers (OR 2.84 95%CI 0.62–13.05), rubber and plastics products machine operators (OR 2.82 95%CI 0.75–10.67), building workers (OR 2.15, 95%CI 0.68–6.73), and female market farmers and crop growers (OR 2.05 95%CI 0.72–5.83). In conclusion, this study has confirmed that hairdressers and sewing machinists are high risk occupations for bladder cancer in New Zealand, and has identified several other occupations and industries of high bladder cancer risk that merit further study.

High risk occupations for non-Hodgkin’s lymphoma in New Zealand: case–control study

Objectives: Previous studies into occupational risk factors for non-Hodgkin’s lymphoma (NHL) in New Zealand have indicated that farmers and meat workers are at increased risk for these neoplasms. A new nationwide case–control study was conducted to assess whether previously observed associations persist and to identify other occupations that may contribute to the risk of NHL in the New Zealand population. Methods: A total of 291 incident cases of NHL (age 25–70 years) notified to the New Zealand Cancer Registry during 2003 and 2004, and 471 population controls, were interviewed face-to-face. The questionnaire collected demographic information and a full occupational history. The relative risk for NHL associated with ever being employed in particular occupations and industries was calculated by unconditional logistic regression adjusting for age, sex, smoking, ethnicity and socioeconomic status. Estimates were subsequently semi-Bayes adjusted to account for the large number of occupations and industries being considered. Results: An elevated NHL risk was observed for field crop and vegetable growers (OR 2.74, 95% CI 1.04 to 7.25) and horticulture and fruit growing (OR 2.28, 95% CI 1.37 to 3.79), particularly for women (OR 3.44, 95% CI 0.62 to 18.9; OR 3.15, 95% CI 1.50 to 6.61). Sheep and dairy farming was not associated with an increased risk of NHL. Meat processors had an elevated risk (OR 1.97, 95% CI 0.97 to 3.97), as did heavy truck drivers (OR 1.98, 95% CI 0.92 to 4.24), workers employed in metal product manufacturing (OR 1.92, 95% CI 1.12 to 3.28) and cleaners (OR 2.11, 95% CI 1.21 to 3.65). After semi-Bayes adjustment the elevated risks for horticulture and fruit growing, metal product manufacturing and cleaners remained statistically significant, representing the most robust findings of this study. Conclusions: This study has confirmed that crop farmers and meat workers remain high risk occupations for NHL in New Zealand, and has identified several other occupations and industries of high NHL risk that merit further study.

Lung cancer and occupation: A new zealand cancer registry‐based case–control study

BACKGROUND There are many proven and suspected occupational causes of lung cancer, which will become relatively more important over time, as smoking prevalence decreases. METHODS We interviewed 457 cases aged 20-75 years notified to the New Zealand Cancer Registry during 2007-2008, and 792 population controls. We collected information on demographic details, potential confounders, and employment history. Associations were estimated using logistic regression adjusted for gender, age, ethnicity, smoking, and socio-economic status. RESULTS Among occupations of a priori interest, elevated odds ratios (ORs) were observed for sawmill, wood panel and related wood-processing plant operators (OR 4.63; 95% CI 1.05-20.29), butchers (OR 8.77, 95% CI 1.06-72.55), rubber and plastics products machine operators (4.27; 1.16-15.66), heavy truck drivers (2.24; 1.19-4.21) and workers in petroleum, coal, chemical and associated product manufacturing (1.80; 1.11-2.90); non-significantly elevated risks were also observed for loggers (4.67; 0.81-27.03), welders and flame-cutters (2.50; 0.86-7.25), pressers (5.74; 0.96-34.42), and electric and electronic equipment assemblers (3.61; 0.96-13.57). Several occupations and industries not of a priori interest also showed increased risks, including nursing associate professionals (5.45; 2.29-12.99), enrolled nurses (7.95; 3.10-20.42), care givers (3.47; 1.40-8.59), plant and machine operators and assemblers (1.61; 1.20-2.16), stationary machine operators and assemblers (1.67; 1.22-2.28), food and related products processing machine operators (1.98; 1.23-3.19), laborers and related elementary service workers (1.45; 1.05-2.00), manufacturing (1.34; 1.02-1.77), car retailing (3.08; 1.36-6.94), and road freight transport (3.02; 1.45-6.27). CONCLUSIONS Certain occupations and industries have increased lung cancer risks in New Zealand, including wood workers, metal workers, meat workers, textile workers and drivers. Am. J. Ind. Med. 54:89-101, 2011.

Leukaemia and occupation: a New Zealand Cancer Registry-based case–control Study

BACKGROUND To examine the association between occupation and leukaemia. METHODS We interviewed 225 cases (aged 20-75 years) notified to the New Zealand Cancer Registry during 2003-04, and 471 controls randomly selected from the Electoral Roll collecting demographic details, information on potential confounders and a comprehensive employment history. Associations between occupation and leukaemia were analysed using logistic regression adjusted for gender, age, ethnicity and smoking. RESULTS Elevated odds ratios (ORs) were observed in agricultural sectors including horticulture/fruit growing (OR: 2.62, 95% confidence interval (CI): 1.51, 4.55), plant nurseries (OR: 7.51, 95% CI: 1.85, 30.38) and vegetable growing (OR: 3.14, 95% CI: 1.18, 8.40); and appeared greater in women (ORs: 4.71, 7.75 and 7.98, respectively). Elevated ORs were also observed in market farmers/crop growers (OR: 1.84, 95% CI: 1.12, 3.02), field crop/vegetable growers (OR: 3.98, 95% CI: 1.46, 10.85), market gardeners (OR: 5.50, 95% CI: 1.59, 19.02), and nursery growers/workers (OR: 4.23, 95% CI: 1.34, 13.35); also greater in women (ORs: 3.48, 7.62, 15.74 and 11.70, respectively). These elevated ORs were predominantly for chronic lymphocytic leukaemia (CLL). Several associations persisted after semi-Bayes adjustment. Elevated ORs were observed in rubber/plastics products machine operators (OR: 3.76, 95% CI: 1.08, 13.08), predominantly in plastic product manufacturing. CLL was also elevated in tailors and dressmakers (OR: 7.01, 95% CI: 1.78, 27.68), cleaners (OR: 2.04, 95% CI: 1.00, 4.14) and builders labourers (OR: 4.03, 95% CI: 1.30, 12.53). CONCLUSIONS These findings suggest increased leukaemia risks associated with certain agricultural, manufacturing, construction and service occupations in New Zealand.

Morbidity in former sawmill workers exposed to pentachlorophenol (PCP): a cross-sectional study in New Zealand.

BACKGROUND From 1950 to 1990 pentachlorophenol (PCP) was used widely in the New Zealand sawmill industry, and persistent claims of long-term health effects have been made. METHODS We surveyed surviving members of a cohort enumerated to study mortality in sawmill workers employed from 1970 to 1990. Estimates of historical exposure were based on job titles held, using the results of a PCP biomonitoring survey conducted in the 1980s. The survey involved interviews and clinical examinations, with interviewers and examiners blinded to exposure status. RESULTS Of the 293 participants 177 had not been exposed, and of the 116 exposed all but 10% had low or short-term PCP exposure. Nevertheless, a number of significant associations between PCP exposure and the prevalence of various symptoms were observed including associations between: (i) exposure levels and self-reported tuberculosis, pleurisy or pneumonia (P < 0.01) and a deficit in cranial nerve function (P = 0.04); (ii) duration of employment and thyroid disorders (P = 0.04), and neuropsychological symptoms including often going back to check things (P = 0.04), low libido (P = 0.02) and heart palpitations (P = 0.02), and a strong dose-response trend for frequent mood changes without cause (P < 0.01); and (iii) cumulative exposure and frequent mood changes without cause (P = 0.02), low libido (P = 0.04), and in the overall number of neuropsychological symptoms reported (P = 0.03). CONCLUSIONS PCP exposure was associated with a number of physical and neuropsychological health effects that persisted long after exposure had ceased.

Serum dioxin levels in former New Zealand sawmill workers twenty years after exposure to pentachlorophenol (PCP) ceased

From the 1950s to the late 1980s pentachlorophenol (PCP) based anti-sapstain fungicides were widely used in the New Zealand timber industry. Workers involved in treatment, or those handling freshly treated timber, experienced significant PCP exposure. Commercial grade PCP contained contaminants including 2,3,7,8-substituted polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) congeners. To determine whether PCP exposure had resulted in elevated serum dioxin levels twenty years after its use had ceased we tested 94 former sawmill workers randomly selected from surviving members of a cohort enumerated for a mortality and cancer incidence study. After interviewing these individuals to collect demographic data and a comprehensive work history, they were divided into 71 PCP-exposed and 23 non-exposed individuals on the basis of job title and work tasks performed. We compared age-adjusted dioxin levels in the exposed and non-exposed groups, examined the effect of PCP exposure duration and intensity, and compared congener profiles with those found in the commercial grade PCP used at the time. Mean levels in exposed workers were elevated when compared with the non-exposed, with levels of 1,2,3,6,7,8-HxCDD, 1,2,3,4,6,7,8-HpCDD and OCDD being two to three times higher. The congener profiles in serum were consistent with those in PCP solutions, and dioxin levels increased with both employment duration and estimated exposure intensity. Serum dioxin levels in former New Zealand sawmill workers remain elevated twenty years after exposure to PCP ceased, and reflect the pattern of past PCP exposure.

The distribution of occupations in two populations with upper limb pain.

Abstract Occupations of two geographically distinct populations of patients with upper limb pain were examined. Relative risks for being in an occupation were calculated for subjects with epicondylitis, carpal tunnel syndrome, and pain syndromes in one population and nonspecific occupational overuse syndrome (OOS) in the other. Population A subjects (806 female, 154 male Auckland clinic referrals) with epicondylitis and carpal tunnel syndrome had higher rates of manual occupations compared with the Auckland employed population, consistent with previous research. Both Population A and Population B subjects (1,188 female, 499 male national notifications to the Department of Labour) with pain syndrome or nonspecific OOS had increased rates of clerical occupations. Relative risks ranged from 2.24 (95% CI 1.69,2.97) to 3.92 (3.50 ,4.40). Word processor operators, data-entry operators, and mail sorters were overrepresented in both populations. An unexplained association between nonspecific upper arm pain and being in some clerical occupations requires further research.

Occupational bladder cancer in New Zealand: a 1-year review of cases notified to the New Zealand Cancer Registry.

Abstract

Sex ratio of the offspring of New Zealand phenoxy herbicide producers exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin

Objectives Exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) has inconsistently been associated with a decreased sex ratio of the offspring (number of male births divided by total births). We conducted a study among men and women who were employed in a New Zealand phenoxy herbicide production plant between 1969 and 1984, to study their offspring sex ratio in relation to their back-calculated TCDD serum concentrations determined in 2007/2008. Methods A total of 127 men and 21 women reported that 355 children were conceived after starting employment at the plant. The association between their lipid-standardised TCDD serum concentrations back-calculated to the time of their offsprings birth and the probability of a male birth was estimated through logistic regression, adjusting for the age of the exposed parent at birth, current body mass index and smoking. Results The overall sex ratio was 0.55 (197 boys, 158 girls). For fathers with serum TCDD concentrations ≥20 pg/g lipid at time of birth, the sex ratio was 0.47 (OR 0.49; 95% CI 0.30 to 0.79). The probability of a male birth decreased with higher paternal serum TCDD at time of birth (<4; 4–20; 20–100; ≥100 pg/g lipid), with ORs of 1.00 (reference); 1.00 (95% CI 0.50 to 2.02); 0.52 (95% CI 0.29 to 0.92); 0.45 (95% CI 0.23 to 0.89), p trend 0.007. For exposed mothers, the sex ratio was not reduced. Conclusions This study indicates that paternal serum TCDD concentrations in excess of an estimated 20 pg/g lipid at time of conception are associated with a reduced sex ratio.

Morbidity in New Zealand pesticide producers exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD).

OBJECTIVES To conduct a cross-sectional morbidity survey among 245 former employees of a pesticide production plant exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in New Zealand. METHODS Demographic factors and health information were collected in face-to-face interviews. TCDD, lipids, thyroid hormones, glucose and immunoglobulin G (IgG) were determined in non-fasting blood. For 111 participants, a neurological examination was conducted. Associations between health outcomes and working in a TCDD exposed job (prevalence 49%) and serum TCDD concentration≥10pg/g lipid (18%) were assessed using logistic regression whilst controlling for age, gender, smoking, body mass index and ethnicity. RESULTS Diabetes was more common in those who had worked in TCDD exposed jobs (OR 4.0, 95%CI 1.0-15.4) and in those with serum TCDD ≥10pg/g (OR 3.1, 95%CI 0.9-10.7). Non-fasting glucose levels >6.6mmol/l were more common in those with TCDD exposed jobs (OR 3.6, 95%CI 1.0-12.9), as were serum free thyroxine 4<12.8pmol/l (OR 4.5, 95%CI 1.4-14.4), triglycerides >1.7mmol/l (OR 2.5, 95%CI 1.1-5.7) and high density lipoprotein cholesterol (HDL) <1mmol/l (OR 4.0, 95%CI 1.2-13.2). IgG was negatively associated with TCDD (linear regression p=0.05). The neurological examination revealed a higher frequency of abnormal reflexes in those with serum TCDD ≥10pg/g (OR 4.8, 95%CI 1.1-21.0). CONCLUSIONS In this occupationally exposed population, TCDD was associated with an increased risk of diabetes and a range of subclinical responses in multiple systems (peripheral nervous system, immune system, thyroid hormones and lipid metabolism), several decades after last exposure. These results need to be interpreted with caution due to the small study size and the cross-sectional nature of the study.