Smoking, nutrition, parity and oral contraceptive use have been reported as major environmental risk factors for cervical cancer. After the discovery of the very strong link between human papillomavirus (HPV) infection and cervical cancer, it is unclear whether the association of these environmental factors with cervical cancer reflect secondary associations attributable to confounding by HPV, if they are independent risk factors or whether they may act as cofactors to HPV infection in cervical carcinogenesis. To investigate this issue, we performed a population-based case–control study in the Västerbotten county of Northern Sweden of 137 women with high-grade cervical intra-epithelial neoplasia (CIN 2–3) and 253 healthy age-matched women. The women answered a 94-item questionnaire on diet, smoking, oral contraceptive use and sexual history and donated specimens for diagnosis of present HPV infection (nested polymerase chain reaction on cervical brush samples) and for past or present HPV infections (HPV seropositivity). The previously described protective effects of dietary micronutrients were not detected. Pregnancy appeared to be a risk factor in the multivariate analysis ( P < 0.0001). Prolonged oral contraceptive use and sexual history were associated with CIN 2–3 in univariate analysis, but these associations lost significance after taking HPV into account. Smoking was associated with CIN 2–3 (odds ratio (OR) 2.6, 95% confidence interval (CI) 1.7–4.0), the effect was dose-dependent ( P = 0.002) and the smoking-associated risk was not affected by adjusting for HPV, neither when adjusting for HPV DNA (OR 2.5, CI 1.3–4.9) nor when adjusting for HPV seropositivity (OR 3.0, CI 1.9–4.7). In conclusion, after taking HPV into account, smoking appeared to be the most significant environmental risk factor for cervical neoplasia. © 2000 Cancer Research Campaign

Background: Chronic infections and associated inflammatory markers are suggested risk factors for cardiovascular diseases (CVD) and stroke. The proinflammatory cytokine interleukin (IL)-1β is suggested to play a role in the regulation of local inflammatory responses in both CVD and periodontitis. The leukotoxin from the periodontal pathogen Actinobacillus actinomycetemcomitans has recently been shown to cause abundant secretion of IL-1β from macrophages. The aim of the present study was to compare the prevalence of systemic antibodies to A. actinomycetemcomitans leukotoxin in stroke cases (n = 273) and matched controls (n = 546) in an incident case-control study nested within the Northern Sweden MONICA and Västerbotten Intervention cohorts. Methods: Antibodies to A. actinomycetemcomitans leukotoxin were analyzed in a bioassay with HL-60 cells (leukocytes), purified A. actinomycetemcomitans leukotoxin, and plasma. Plasma samples which inhibited lactate dehydrogenase release from leukotoxin-lysed cells by ≧50% were classified as antibody positive. Results: Antibodies to A. actinomycetemcomitans leukotoxin were detected in 18.8% of the women and 15.2% of the men. Women with those antibodies had a significantly decreased risk for stroke (OR = 0.28, 95% CI: 0.13–0.59), but not men (OR = 0.88, 95% CI: 0.52–1.51). Conclusion: The immunoreactivity to A. actinomycetemcomitans leukotoxin correlates negatively with a future stroke in woman, but not in men. Further studies are needed to explain the underlying mechanisms, as well as the biological relevance of this finding.

BackgroundChronic infections and associated inflammatory markers are suggested risk factors for cardiovascular disease (CVD). The proinflammatory cytokine, interleukin (IL)-1β, is suggested to play a role in the regulation of local inflammatory responses in both CVD and periodontitis. The leukotoxin from the periodontal pathogen Aggregatibacter actinomycetemcomitans has recently been shown to cause abundant secretion of IL-1β from macrophages. The aim of the present study was to compare the prevalence of systemic immunoreactivity to A. actinomycetemcomitans leukotoxin in myocardial infarction (MI) cases (n = 532) and matched controls (n = 1,000) in a population-based case and referents study in northern Sweden.MethodsCapacity to neutralize A. actinomycetemcomitans leukotoxin was analyzed in a bioassay with leukocytes, purified leukotoxin, and plasma. Plasma samples that inhibited lactate-dehydrogenase release from leukotoxin-lysed cells by ≥50% were classified as positive.ResultsNeutralizing capacity against A. actinomycetemcomitans leukotoxin was detected in 53.3% of the plasma samples. The ability to neutralize leukotoxin was correlated to increasing age in men (n = 1,082) but not in women (n = 450). There was no correlation between presence of systemic leukotoxin-neutralization capacity and the incidence of MI, except for women (n = 146). Women with a low neutralizing capacity had a significantly higher incidence of MI than those who had a high neutralizing capacity.ConclusionSystemic immunoreactivity against A. actinomycetemcomitans leukotoxin was found at a high prevalence in the analyzed population of adults from northern Sweden. The results from the present study do not support the hypothesis that systemic leukotoxin-neutralizing capacity can decrease the risk for MI.