Questionnaires case-control studies

An inverse correlation between thyroid cancer risk and phytoestrogens was recently proposed as a result of a multi-ethnic population-based case control study conducted in the San Francisco Bay Area (Hom-Ross et al., 2002). In this study, dietary habits and phytoestrogen consumption were assessed by a food-frequency questionnaire and by a nutrient database. The outcome of the study was that soy-based foods and alfalfa sprouts were associated with a reduction of thyroid cancer risk, whereas a Western diet did not influence cancer risk. No difference was observed between American and Asian women or between pre- and postmenopausal women. Furthermore, among the few compounds examined, the isoflavones genistein and daidzein and the lignan secoisolariciresinol were the phytoestrogens most frequently associated with risk reduction (Horn-Ross et al., 2002). 

In Greece, a case-control study was conducted to investigate the incidence of liver cancer by estimating the consumption of six types of flavonoids with a semiquantitative questionnaire on the frequency of foods. The intake of flavones was inversely associated with hepatocellular carcinoma, irrespective of its etiology (viral or nonviral). With respect to cholangiocarcinoma, an inverse association with the consumption of flavan-3-ols, anthocyanidins, and total flavonoids studied was found. However, this last result should be viewed with caution because of the small sample size, due to the fact that this is a rare type of cancer (Lagiou and others 2008). 

In a case-control study in the north of Sweden, Hallquist et al. (1993) compared 188 men and women aged 20-70 years who had thyroid cancer with age- and sex-matched controls (two per case) selected from a register of the local population. The cases were identified retrospectively from a cancer registry and excluded a proportion of patients (19%) who had died by the time of the study. Exposure to potential risk factors, including chlorophenols, was ascertained by postal questionnaire with a supplementary telephone interview if answers were incomplete. The response rates for the cases and controls were 95% and 90%, respectively. Of the 171 cases analysed, 107 had papillary tumours. Four cases and three controls reported exposure to chlorophenols (odds ratio, 2.8 95% CI, 0.5-18). [The Working Group noted that the method of statistical analysis was not the most appropriate for individually matched data, but this is unlikely to have produced serious bias.]... 

A case control study by Salib and Hillier (1996) examined the possible relationship between the risk of Alzheimer s disease and occupational exposure to airborne aluminum. The occupation histories of patients with a clinical diagnosis of Alzheimer s disease (198 cases) were compared with two control groups patients with dementia other than Alzheimer s disease (164 cases) and patients with diagnoses other than dementia. Occupational histories were obtained from the patients via a questionnaire. No significant association between occupational exposure to aluminum dust or fumes and the risk of Alzheimer s disease were found (the odds ratio for the comparison with all controls was 0.98, 95% confidence interval of 0.53-1.75). 

Example 3. Butler et al. (2003) conducted a population-based case-control study that evaluated levels of HCAs, meat intake according to doneness and cooking method, and the risk of colon cancer. The study population consisted of participants selected from 33 counties in North Carolina who were part of the North Carolina Colon Cancer Study. Cases included 274 blacks and 346 whites, between the ages of 40 and 84 with invasive adenocarcinoma of the colon diagnosed from 1996 to 2000. Controls, 426 blacks and 611 whites, were randomly selected from the North Carolina Division of Motor Vehicles (under 65) and the Center for Medicare and Medicaid services (over 65). Exposure was assessed using a food-frequency questionnaire. Meat intake frequency data, cooking method, and level of doneness was used to estimate exposure values for three specific HCAs. (Results of this study are discussed in Section 26.2.2b.). Source Butler et al. (2003). 

The biomarker is validated in a cross-sectional population-based study to determine if there are correlations between self-reported HCA exposure (for example, food frequency questionnaire using photographs similar to the case-control study reported by Butler et al.) and HCA measurements. 

Other data sets, with a broader coverage of jobs throughout the population, are likely to be needed for estimation of pesticide exposures in case-control studies. For example, Stewart and co-workers (Stewart and Stewart, 1994 Stewart et al, 1998) have used detailed occupational questionnaires with job-specific modules, together with data from the US Occupational Safety and Health Administration (OSHA) Integrated Management Information System to aid in assigning study subjects exposures to multiple chemicals, including pesticides. 

Rocca, W.A., L. Fratiglioni, D.P. Bracco, C. Groppi and B.S. Schoenberg (1986). The use of surrogate respondents to obtain questionnaire data in case-control studies of neurologic diseases, J. Chronic Diseases, 39, 907-912. 

Stewart, P.A., W.F. Stewart, J. Siemiatycki, E.F. Heineman and D. Mustafa (1998). Questionnaires for collecting detailed occupational information for community-based case control studies. Am. Ind. Hyg. Assoc. J., 58, 39-44. 

A case-control study was designed to explore risk factors for colorectal adenomas. Adenomas are precursors to 80-90% of all colorectal cancers. The study used 236 cases (with adenomas or polyps) and 409 controls (no adenomas) (Tseng ef aF., 1996) (Tabic 11,2). All subjects were patients receiving colonoscopy exams. The subjects were not recruited from the general public, A month or so after the exam, the subjects were asked to fill out a food choice questionnaire. 

The second study was a Swedish nationwide, population-based, case-control study of early-stage chronic renal insufficiency in men whose serum creatinine concentration exceeded 3.4 mg/dl (300 pmol/l) or women whose serum creatinine exceeded 250 pmoPl (2.8 mg/dl) (32). In all, 918 patients with newly diagnosed renal insufficiency and 980 controls were interviewed and completed questionnaires about their lifetime consumption of... 

Studies regarding the developmental toxicity of airborne formaldehyde in humans are limited to a population-based case-control study of 244 mothers with low-birth weight newborns in Lithuania compared with 4,089 control mothers with normal weight newborns (Graz ulevi iene et al. 1998). Questionnaire information was collected from cases and controls for risk factors including place of residence. Based on air monitoring data, residential districts were grouped into low (mean concentration... 

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