Changing incidence of AIDS-related Kaposi sarcoma and non-Hodgkin lymphoma in Ontario, Canada.

OBJECTIVE: To examine the influence of the AIDS epidemic on the incidence of Kaposi sarcoma (KS) and non-Hodgkin lymphoma (NHL) in Ontario. METHODS: Age-standardized incidence rates for KS and NHL from 1981 to 2000 were calculated from the population-based Ontario Cancer Registry. AIDS cases were extracted from Ontario Ministry of Health and Long-Term Care reports. HIV death data were obtained from the Ontario Cancer Registry. RESULTS: KS was a rare cancer before the 1980s; however, incidence increased sharply between 1985 and 1995 by 13.8% per year. Thereafter, incidence rates fell close to those in the early 1980s. NHL incidence in males increased steadily during the 1980s at 3.2% per year and then slowed beyond 1990. In males aged 30-44, NHL incidence rose from 1981 to 1990 (8.8% per year) and then fell (-2.5%) thereafter. NHL and KS cases represented one-third of HIV deaths. CONCLUSIONS: The AIDS epidemic, the introduction of antiretroviral therapies, and the decrease in HIV infection rates explain the rise and decline of KS incidence in Ontario. NHL incidence trends are more complex, although the AIDS epidemic explains the trends observed in younger men (in whom AIDS is more common), and for the AIDS-related subtypes.

Nonsteroidal antiinflammatory drug use and breast cancer risk: subgroup findings.

Nonsteroidal antiinflammatory drugs (NSAIDs) may play a role in breast cancer prevention; however, breast cancer subtypes and lifestyle/host factors may influence their impact. During 1996-1998 in Canada, the authors examined the association between regular NSAID use (defined as daily use for at least 2 months) and breast cancer risk by estrogen receptor (ER) and progesterone receptor (PR) status, cigarette smoking exposure, and history of arthritis. Breast cancer cases (n = 3,125, including 1,600 ER+PR+ and 591 ER-PR-) and an age-matched, random sample of controls (n = 3,062) completed a general risk factor questionnaire, including detailed questions on prescription and nonprescription NSAID use. NSAID use was associated with reduced risk of breast cancer (odds ratio = 0.76, 95% confidence interval: 0.66, 0.88). The association was not significantly different for ER+PR+ (odds ratio = 0.71, 95% confidence interval: 0.60, 0.84) and ER-PR- cancers (odds ratio = 0.80, 95% confidence interval: 0.62, 1.03) (p(heterogeneity) = 0.66). The magnitude of the NSAID inverse association was similar for women with and without arthritis and across smoking strata (risk estimates ranged from 0.74 to 0.84). Breast cancer risk tended to decrease with increasing duration of NSAID use and was generally lowest for >or=7 years of use, and both acetylsalicylic acid and non-acetylsalicylic acid use were associated with reduced risks.

Ambient UV, personal sun exposure and risk of multiple primary melanomas.

OBJECTIVE: Sun exposure is the main cause of melanoma in populations of European origin. No previous study has examined the effect of sun exposure on risk of multiple primary melanomas compared with people who have one melanoma. METHODS: We identified and enrolled 2,023 people with a first primary melanoma (controls) and 1,125 with multiple primary melanomas (cases) in seven centers in four countries, recorded their residential history to assign ambient UV and interviewed them about their sun exposure. RESULTS: Risk of multiple primary melanomas increased significantly (P<0.05) to OR=2.10 for the highest exposure quarter of ambient UV irradiance at birth and 10 years of age, to OR=1.38 for lifetime recreational sun exposure, to OR=1.85 for beach and waterside activities, to OR=1.57 for vacations in a sunnier climate, to OR=1.50 for sunburns. Occupational sun exposure did not increase risk (OR=1.03 for highest exposure). Recreational exposure at any age increased risk and appeared to add to risk from ambient UV in early life. CONCLUSIONS: People who have had a melanoma can expect to reduce their risk of a further melanoma by reducing recreational sun exposure whatever their age. The same is probably true for a person who has never had a melanoma.

Predictors of self-reported confidence ratings for adult recall of early life sun exposure.

Use of self-reported confidence ratings may be an efficient method for assessing recall bias. In this exploratory application of the method, the authors examined the relation between case-control status and self-reported confidence ratings. In 2002 and 2003, melanoma cases (n = 141) and controls (n = 143) aged 20-44 years residing in Ontario, Canada, estimated the amounts of time they had spent outdoors in summer activities when they were 6-18 years of age and indicated their confidence in the accuracy of each estimate. The generalized estimating equations extension of logistic regression was used to examine dichotomized confidence ratings (more confident vs. less confident) for activities reported for ages 6-11 years and 12-18 years. Types of activity were associated with more confident reporting for both age strata; as the number of stable outdoor activity periods (total number of similar outdoor periods within each activity) reported by respondents increased, confidence decreased. Cumulative time spent outdoors was also associated with more confidence but reached statistical significance only for the age stratum 12-18 years. There was no statistically significant association between case-control status and self-reported confidence for either age stratum (6-11 years: odds ratio = 0.91; 12-18 years: odds ratio = 1.32), which suggests an absence of recall bias for reported time spent outdoors.

Hormonal factors and the risk of breast cancer according to estrogen- and progesterone-receptor subgroup.

Evidence suggests hormonal factors may be more strongly associated with estrogen receptor+progesterone receptor+ (ER+PR+) than ER-PR- breast cancer risk. This study evaluated risk factors according to ERPR tumor status among pre- and postmenopausal women participating in two recent population-based case-control studies. Breast cancer cases, ages 25-74 years, and diagnosed 1995-1998 were sampled from the Ontario Cancer Registry. Controls were a random sample of women identified using the Ontario Ministry of Finance rolls and were frequency-matched to cases within 5-year age groups. Epidemiological data were collected from breast cancer cases and controls using two self-administered questionnaires. ERPR data were obtained for 87% of the breast cancer cases (3,276 of 3,748). Multivariate polytomous logistic regression was used to obtain odds ratios estimates and 95% confidence intervals. The following significant differences were observed in the risk factor profiles for ER+PR+ and ER-PR- breast cancer: among premenopausal women, late age at menarche was only associated with a reduction in ER+PR+ breast cancer risk; obesity was associated with an increased ER-PR- and decreased ER+PR+ cancer risk; and the association between alcohol intake and breast cancer risk was heterogeneous across ERPR subgroups, although the direction varied across the levels of alcohol intake. Among postmenopausal women, there were no statistically significant differences observed in the risk factor profiles for ER+PR+ and ER-PR- breast cancer. Some heterogeneity exists in the risk factor profiles of ER+PR+ and ER-PR- premenopausal breast cancer; however, risk factor profiles did not differ markedly for postmenopausal breast cancer.

Evaluation of a risk factor survey with three assessment methods.

This paper describes the evaluation of questions on a cancer risk factor survey using three different methods: dataset response patterns, qualitative feedback, and questionnaire appraisal. These methods addressed the survey data, procedures and questions. The three methods identified similar issues but also made unique contributions. Dataset response patterns showed missing and out-of-range data, an order effect, and mixed coding. Qualitative feedback revealed lack of clarity, sensitive topics, technical or undefined terms, failure to hear all response options, overlapping response options (as perceived by respondents), coding problems and recall difficulties. Questionnaire appraisal showed technical or undefined terms, complex syntax, hidden definitions, and ambiguous wording. The survey assessment methods described here can improve data quality, especially when limited time and resources preclude in-depth questionnaire development.