Reliability of data from next-of-kin: results from a case-control study of occupational and lifestyle risk factors for cancer

Dose-response-relationship between occupational exposure to diesel engine emissions and lung cancer risk: A systematic review and meta-analysis

BACKGROUND

In 2012, the International Agency for Research on Cancer (IARC) concluded that diesel engine emissions (DEE) emissions cause cancer in humans. However, there is still controversy surrounding this conclusion, due to several studies since the IARC decision citing a lack of evidence of a dose-response relationship.

OBJECTIVES

Through a systematic review, we aimed to evaluate all evidence on the association between occupational DEE and lung cancer to investigate whether there is an increased risk of lung cancer for workers exposed to DEE and if so, to describe the dose-response relationship.

METHODS

We registered the review protocol with PROSPERO and searched for observational studies in relevant literature databases. Two independent reviewers screened the studies' titles/abstracts and full texts, and extracted and assessed their quality. Studies with no direct DEE measurement but with information on length of exposure for high-risk occupations were assigned exposure values based on the DEE Job-Exposure-Matrix (DEE-JEM). After assessing quality and informativeness, we selected appropriate studies for the dose-response meta-analysis.

RESULTS

Sixty-five reports (from thirty-seven studies) were included in the review; one had a low risk of bias (RoB) (RR per 10 μg/m3-years: 1.014 [95%CI 1.007-1.021]). There was an increased, statistically significant risk of lung cancer with increasing DEE exposure for all studies (RR per 10 μg/m3-years = 1.013 [95%CI 1.004-1.021]) as well as for studies with a low RoB in the exposure category (RR per 10 μg/m3-years = 1.008 [95% CI1.001-1.015]). We obtained a doubling dose of 555 μg/m3-years for all studies and 880 μg/m3-years for studies with high quality in the exposure assessment.

DISCUSSION

We found a linear positive dose-response relationship for studies with high quality in the exposure domain, even though all studies had an overall high risk of bias. Current threshold levels for DEE exposure at the workplace should be reconsidered.

Accuracy of Smoking Status Reporting: Proxy Information in a Rapidly Fatal Cancer Setting

Objective

To assess whether patients and relatives can serve as reliable proxy reporters of other family members’ cigarette-smoking history.

Patients and Methods

Two samples (325 patients, 707 relatives) were identified from the Mayo Clinic Biospecimen Resource for Pancreas Research, enrolled from November, 6, 2000, to March 15, 2018. Smoking-history data, including categorical (ever/never) and quantitative (packs per day and years smoked) smoking measures, were obtained from self-completed questionnaires by patients and relatives. Relative reports were compared with patient reports on self; patient reports were compared with relative reports on self.

Results

Overall, spouses and first-degree relatives (FDRs) were accurate (94.5%) when reporting patient ever smoking; spouse reports were 98.6% sensitive and 97.7% accurate. Accuracy of patient reports was 97.8% for spouse smoking and 85.5% for FDR smoking; accuracy varied by relationship of FDR. When not concordant, patients generally over-reported daily packs smoked by relatives and under-reported years smoked. Within a 25% agreement range, spouse reports about patients’ daily packs smoked was 46.7%, and years smoked was 69.6%, whereas FDRs were 50% and 64.6%, respectively. When not concordant, relatives generally over-reported daily packs smoked by patients, but no consistent pattern was observed of over- or under-reporting years smoked by patients.

Conclusions

Patients and relatives can be reliable proxies for smoking history (ever/never) in their family members, especially spouses. An accurate reporting of smoking status will help physicians to better gauge performance status and family smoking exposures to inform disease management.

Tobacco smoking and alcohol consumption as risk factors for thymoma - A European case-control study

PURPOSE

Hardly anything is known about the aetiology of thymoma. This paper presents data regarding tobacco smoking and alcohol consumption in relation to thymoma from the first case-control study performed on this rare tumour.

METHODS

A European multi-centre case-control study including incident cases aged 35-69 years with thymoma between 1995 and 1997, was conducted in seven countries. A set of controls, used in seven parallel case-control studies by the same research group was used, including population-based controls from five countries and hospital controls with colon cancer from two countries. Altogether 103 cases, accepted by a reference pathologist, 712 colon cancer controls, and 2071 population controls were interviewed.

RESULTS

Tobacco smoking was moderately related with thymoma (OR 1.4, 95% CI 0.9-2.2), and a tendency to dose-response was shown (p = 0.04), with an increased risk for heavy smokers defined as ≥41 pack-years (OR 2.1, 95% CI 1.1-3.9). A high consumption of spirits defined as ≥25 g of alcohol per day was associated with an increased risk of thymoma (OR 2.4, 95% CI 1.1-5.4), whereas no association was found with beer or wine.

CONCLUSIONS

Tobacco smoking and a high intake of spirits were indicated as risk factors for thymoma.

Occupational exposure to chlorinated and petroleum solvents and mycosis fungoides

OBJECTIVE

To evaluate the potential association between occupational exposure to chlorinated and petroleum solvents and mycosis fungoides (MF).

METHODS

A questionnaire on lifetime job history was administered to 100 patients diagnosed with MF and 2846 controls. Odds ratios (ORs) were calculated as the measure of the association between exposure to each specific solvent and MF.

RESULTS

In the total sample and in men, cases and controls did not differ in relation to exposure to any of the solvents studied. In women, an association with MF was seen for the highest level of estimated exposure to perchloroethylene (OR = 11.38; 95% confidence interval: 1.04 to 124.85) and for exposure less than the median to kerosene/fuel/gasoil (OR = 8.53; 95% confidence interval: 1.11 to 65.62).

CONCLUSIONS

These results do not provide conclusive evidence that exposure to solvents may increase risk of MF because they were not found in men.

Validation of smoking history in cancer patients

OBJECTIVE

The aim of the study was to investigate the agreement between patient records and the information reported from relatives, and how the relationship and time since patient's death affected the response rate and the quality of the data.

METHODS

A questionnaire regarding smoking history was sent to next-of-kin of 270 deceased women diagnosed with breast cancer during 1958-2000 in the Stockholm County. Agreement between the reports of next-of-kin and patient records was calculated using a kappa statistics, along with its 95% confidence interval.

RESULTS

When information about overall smoking history from patient records and next-of-kin was compared, the kappa value was 0.83 (95% confidence interval (CI): 0.73-0.92). Using two smoking categories (<or=15 cigarettes,>15 cigarettes), for quantitative smoking history the kappa value was 0.46. No evidence of a trend toward under-/over-reporting among next-of-kin was found. The overall smoking agreement between medical record and next-of-kin was similar for the two median recall periods (<or=10 years and >10 years), with kappa value 0.80 and 0.83, respectively.

CONCLUSION

Next-of-kin can provide reliable information with almost perfect agreement with patient records on lifetime smoking status, and should be considered in studies where information on smoking history is missing.

Self-maintenance Habits and Preferences in Elderly (SHAPE): reliability of reports of self-care preferences in older persons

BACKGROUND AND AIMS

Self-care preferences can be used in designing programs of care. Yet little has been documented concerning the self-care habits and preferences of older adults.

METHODS

This study assessed the reliability of reports of self-care preferences and their importance among older adults using the Self-maintenance Habits and Preferences in Elderly (SHAPE) instrument. Twenty community-dwelling seniors completed the SHAPE questionnaire twice within a one- to two-week interval. Percent agreement, both exact and close/partial, was computed to assess the reliability of preference content, and intra-class correlations (ICCs) were used for preference importance. Test and subject factors affecting reliability were also investigated.

RESULTS

Exact agreement rate for item content was 73%, and that for close/partial agreement was 93%. Mean ICC for item importance was 0.72. Reliability was greater for dichotomous items than for either ordinal or categorical questions. Reliability of item content varied with number of response options and importance reliability varied with age and IADL status.

CONCLUSIONS

Information from SHAPE about self-care preferences can be used to plan services for seniors and to individualize care for older persons, especially those transitioning to new living environments or those receiving home care.

European multi-centre case-control study on risk factors for rare cancers of unknown aetiology

To search for occupational risk factors, we conducted a case-control study in nine European countries of cancers of the small intestine, male gall bladder, thymus, bone, male breast, melanoma of the eye, and mycosis fungoides. Recruitment was population based in Denmark, Latvia, France, Germany, Italy, and Sweden, from hospital areas in Spain and Portugal, and from one United Kingdom (UK) hospital. We recruited 1457 cases (84% interviewed). Numbers identified corresponded to those in the EUROCIM database for Denmark, but were below those observed for France, Italy and Sweden in the database. We recruited 3374 population (61% interviewed) and 1284 colon cancer controls (86% interviewed). It was possible to undertake this complicated study across Europe, but we encountered three main problems. It was difficult to ensure complete case ascertainment, for population controls, we found a clear divide in the response rate from 75% in the South to only 55% in the North, and a somewhat selective recruitment was noted for the colon cancer controls. The study showed there is a clear dose-response relationship between alcohol intake and the risk of male breast cancer, and an excess risk of mycosis fungoides among glass formers, pottery and ceramic workers. Further data are expected.

Colon cancer controls versus population controls in case-control studies of occupational risk factors

Background

Since updated population registers do not exist in many countries it is often difficult to sample valid population controls from the study base to a case-control study. Use of patient controls is an alternative option if the exposure experience under study for these patients are interchangeable with the experience for population controls. Patient controls may even be preferable from population controls under certain conditions. In this study we examine if colon cancer patients can serve as surrogates for proper population controls in case-control studies of occupational risk factors.

Methods

The study was conducted from 1995 to 1997. Incident colon cancer controls (N = 428) aged 35–69 years with a histological verified diagnosis and population controls (N = 583) were selected. Altogether 254 (59%) of the colon cancer controls and 320 (55%) of the population controls were interviewed about occupational, medical and life style conditions.

Results

No statistical significant difference for educational level, medical history or smoking status was seen between the two control groups. There was evidence of a higher alcohol intake, less frequent work as a farmer and less exposure to pesticides among colon cancer controls.

Conclusions

Use of colon cancer controls may provide valid exposure estimates in studies of many occupational risk factors for cancer, but not for studies on exposure related to farming.