Pregnancy and risk of renal cell cancer: a population-based study in Sweden.

Epidemiological findings indicate that hormonal influences may play a role in the etiology of renal cell cancer (RCC). The possible effect of childbearing remains enigmatic; while some investigators have reported a positive association between number of births and renal cell cancer risk, others have not. A case-control study, nested within a nation-wide Fertility Register covering Swedish women born 1925 and later, was undertaken to explore possible associations between parity and age at first birth and the risk of renal cell cancer. Among these women a total of 1465 cases of RCC were identified in the Swedish Cancer Register between 1958 and 1992 and information on the number of live childbirths and age at each birth was obtained by linkage to the Fertility Database. For each case, five age-matched controls were randomly selected from the same register. Compared to nulliparous women, ever-parous women were at a 40% increased risk of RCC (Odds Ratio [OR]=1.42; 95% CI 1.19-1.69). The corresponding OR for women of high parity (five or more live births) was 1.91 (95% CI 1.40-2.62). After controlling for age at first birth among parous women, each additional birth was associated with a 15% increase in risk (OR=1.15; 95% CI 1.08-1.22). The observed positive association between parity and renal cell cancer risk is unlikely to be fully explained by uncontrolled confounding, but warrants further evaluation in large studies, with allowance for body mass index.

Risk factors for sudden infant death syndrome: changes associated with sleep position recommendations.

OBJECTIVE: To quantify the decreased incidence of sudden infant death syndrome (SIDS) and investigate risk profile changes associated with changes in infant sleep position. DESIGN: A population-based case-control study that used birth and death certificates from Washington State. Cases (n = 1515) were all singletons born in Washington between 1985 and 1995 (excluding 1991) who died of SIDS. Control cases (n = 6060) were randomly selected singletons born in the same period who did not die of SIDS. Multivariate logistic regression compared changes in the magnitude of associations between risk factors and SIDS before and after 1991. RESULTS: The incidence of SIDS in Washington declined from 2.6 (1985) to 1.0 (1998) per 1000 births. Over time, the risk of SIDS increased for low birth weight infants (odds ratio [OR] 2.1 rose to 3.6), and infants born to mothers who were smokers (OR 2.7 rose to 3.7), unmarried (OR 1.4 rose to 2.0), black (OR 1.4 rose to 2.5), or received limited prenatal care (OR 1.5 rose to 2.5). CONCLUSION: Five exposures were associated with increased risks of SIDS. These may not require a prone sleep position for their deleterious impact being associated with distinct causal pathways, or possibly indicating subpopulations yet to recognize the importance of the supine sleep position.

Recreational physical activity and risk of papillary thyroid cancer (United States).

OBJECTIVE: Exercise has been hypothesized to influence cancer risk through a variety of mechanisms including hormonal, metabolic and immunologic effects, yet its relation with the risk of thyroid cancer has not been examined. We conducted a population-based case-control study in women aged 18-64 in three counties of western Washington State to assess the relation of recreational physical activity with risk of papillary thyroid cancer. METHODS: Of 558 women with thyroid cancer of the follicular epithelium diagnosed during 1988-1994 who were identified as eligible, 468 (83.9%) were interviewed; this analysis was restricted to women with papillary histology (n = 410). Controls (n = 574) were identified by random digit dialing, with a response proportion of 73.6%. Logistic regression was used to calculate odds ratios (OR) and associated confidence intervals (CI) estimating the relative risk of papillary thyroid cancer associated with various aspects of recreational exercise. RESULTS: Risk of thyroid cancer was reduced among women who reported that they engaged in regular recreational exercise during the 2 years before diagnosis relative to women who did not report exercise during that time period (OR = 0.76, 95% CI 0.59-0.98). A similar risk reduction was noted among women who reported having exercised regularly between ages 12 and 21 (OR = 0.83, 95% CI 0.64-1.1). However, no clear associations with aspects of recreational activity, including average hours exercised per week or weekly energy expenditure, were observed. CONCLUSIONS: These results provide some initial support for the hypothesis that physical activity may reduce risk of thyroid cancer.

Hypercalcemia in carcinoma of the prostate: case report and review of the literature.

Hypercalcemia developed in a man with recurrent adenocarcinoma of the prostate. Serum calcium became normal soon after bilateral orchiectomy and the patient was free of disease 18 months later. The absence of radiographically detectable bone metastases in this patient suggested a humoral mechanism for the hypercalcemia. Orchiectomy may be an effective treatment for hypercalcemia complicating prostatic carcinoma.