Background: Helicobacter pylori (H. pylori) infection has been reported to be associated with cardiovascular risk factors by inducing chronic low-grade inflammation and by influencing endocrine and metabolic systems, as well as the immunological response evoked by the host. This study investigated the association between H. pylori infection and high density lipoprotein cholesterol (HDL-C) in Japanese subjects.
Methods: The study subjects were 2,632 (1,061 men and 1,571 women) living in rural areas in Japan. We checked H. pylori serum immunoglobulin G (IgG), HDL-C and other cardiovascular risk factors in 1999.
Results: The overall prevalence of H. pylori seropositivity was 53.5% and increased with age. The prevalence was higher among men (58.3%) than women (50.3%). H. pylori seropositive women were more associated with decreased HDL-C than seronegative subjects (58.1±13.6 vs. 60.5±14.7, p<0.01). Multiple linear regression analysis with H. pylori seropositivity, age, body mass index (BMI), fibrinogen, blood glucose, and smoking and alcohol habits demonstrated that H. pylori seropositivity was a significant predictor of decreased HDL-C in women. In addition, there was a linear decrease in HDL-C with increments in the value of H. pylori antibody titer as a continuous variable in women. This association remained in H. pylori seropositive women aged ≥50 years. Moreover, H. pylori seropositive women with BMI <22 were associated with decreased HDL-C, whereas the association was not significant in women with BMI ≥22.
Conclusions: We show that H. pylori seropositivity is associated with decreased HDL-C, especially in women with a lower BMI in rural areas of Japan.

Background: Chronic infections, such as Helicobacter pylori (H. pylori) and Chlamydophila pneumoniae (C. pneumoniae), are known to contribute to atherosclerosis. However, the relationship of the infections to cerebral infarction is still controversial. Methods: The Jichi Medical School (JMS) Cohort Study, a prospective population-based study, investigated the risk factors of cardiovascular disease in Japanese community-dwelling populations. In 1999, we measured serum H. pylori IgG, C. pneumoniae IgG and IgA levels in 2,632 subjects. Logistic regressions were used to analyze associations between H. pylori and C. pneumoniae seropositivities and cerebral infarction. Results: A total of 2,243 subjects were followed up and, during 10.7-years, 64 developed cerebral infarctions, whose prevalence of H. pylori IgG, C. pneumoniae IgG and IgA seropositivities were 51.6%, 71.9%, and 67.2%, respectively. Among seropositive subjects, adjusted odds ratios (ORs) for cerebral infarctions were 1.04 (95% confi dence interval (CI), 0.58-1.87, P=0.89), 2.02 (1.03-3.95, P=0.04), and 1.35 (0.73-2.49, P=0.34) respectively, after adjusting for sex, age, body mass index, total cholesterol, high-density lipoprotein cholesterol, fasting blood sugar, smoking, alcohol, and fi brinogen. C. pneumoniae IgG seropositivities in subjects aged > 65 years were associated with cerebral infarctions, whereas those in subjects aged < 65 years, were not. Conclusions: C. pneumoniae IgG was associated with cerebral infarction, C. pneumoniae IgA and H. pylori IgG were not.