Association of genetic variations in DTNBP1 with cognitive function in schizophrenia patients and healthy subjects.

The dystrobrevin-binding protein 1 gene (DTNBP1) has been regarded as a susceptibility gene for schizophrenia. Recent studies have investigated its role on cognitive function that is frequently impaired in schizophrenia patients, and generated inconsistent results. The present study was performed to elucidate effects of genetic variations in DTNBP1 on various cognitive domains in both schizophrenia patients and healthy subjects. Comprehensive neuropsychological tests were administered to 122 clinically stable schizophrenia patients and 119 healthy subjects. Based on positive findings reported in previous association studies, six SNPs were selected and genotyped. Compared to healthy subjects, schizophrenia patients showed expected lower performance for all of the cognitive domains. After adjusting for age, gender, and educational level, four SNPs showed a nominally significant association with cognitive domains. The association of rs760761 and rs1018381 with the attention and vigilance domain remained significant after applying the correction for multiple testing (P < 0.001). Similar association patterns were observed both, in patients and healthy subjects. The observed results suggest the involvement of DTNBP1 not only in the development of attention deficit of schizophrenia, but also in the inter-individual variability of this cognitive domain within the normal functional range.

Factor structure of the neurocognitive tests: an application of the confirmative factor analysis in stabilized schizophrenia patients.

The purpose of the present study was to identify the factor structure of neurocognitive tests used on schizophrenia patients by using the confirmative factor analysis, and to assess the factor score differences of schizophrenia patients and healthy controls. Comprehensive neurocognitive tests were administered to stabilized schizophrenia patients (N=114) and healthy controls (N=120). In the results of factor analyses on patients, the multifactorial-6-factor model, which included the speed of processing, working memory, verbal learning and memory, visual learning and memory, attention/vigilance, and reasoning/problem solving as suggested by the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS), showed the better goodness of fit than any of the other models tested. And assessing the group differences of factor scores, we found the patients performed worse than the controls in all factors, but the result showed meaningful variations of impairments across the cognitive factors. Our study identifies the six major domains with multifactorial structure of cognitive abilities in schizophrenia patients and confirms the distinctive impairment patterns of each cognitive domain. These results may have utility in better understanding the pathology of schizophrenia as well as in genetic studies.

Mammographic densities and circulating hormones: a cross-sectional study in premenopausal women.

Progestogens appear to influence breast density more than estrogens in postmenopausal women taking hormone replacement therapy (HRT), but little is known about the effect of circulating hormones on mammographic density among premenopausal women. This cross-sectional study explores the relationship of body weight and sex steroids with breast density. Luteal serum samples were analyzed for progesterone, estrone, estradiol, and sex hormone-binding globulin (SHBG). Mammograms were assessed for density using a computer-assisted method. We performed mediation tests using multiple linear regression models. Significant associations of SHBG and estradiol with percentage density disappeared after adjustment for body weight and other covariates, whereas the relationship between progesterone and breast density remained borderline significant. The mediation tests indicated that progesterone has a direct and an indirect effect on mammographic density. Our finding that progesterone shows a stronger association with percentage of mammographic density than estrogen agrees with clinical reports describing denser mammographic patterns among women taking HRT, although these women differ in menopausal status.

The effect of migration on cancer incidence among Japanese in Hawaii.

OBJECTIVES: This analysis compared cancer incidence trends among Japanese in Japan, and Japanese and Caucasians in Hawaii, between 1960 and 1997, and estimated the impact of migration on the incidence of different cancers. METHODS: Incidence information was obtained from 8 volumes of Cancer Incidence in Five Continents. The migration effect was estimated from the areas under the incidence curves as the ratio of the geographic and the ethnic difference in cumulative cancer incidence. RESULTS: Among the 5 more common cancers, the migrant effect was strongest for colon and stomach cancers, prostate and breast cancers were affected to a lesser degree, and lung cancer risk differed little between Japanese in Japan and Hawaii. Migration led to lower risk of stomach, esophageal, pancreatic, liver, and cervical cancers, but to higher rates for all other cancers. The large variation in time for migrants to adopt the host population's cancer risk suggests that risk factors have organ-specific effects, or operate at different times in life. Although the available incidence rates are limited by under-reporting and early detection efforts, mortality rates confirm the significant differences in cancer risk. CONCLUSIONS: The persistent difference in cancer incidence several generations after migration supports the idea that living in the host country is not, alone, sufficient to modify cancer risk for all cancer sites to the level of the host population. Although the migration effect can be partially explained by known etiologic factors, a large proportion of the changing risk remains unexplained.

Association of seasonality and premenstrual symptoms in bipolar I and bipolar II disorders.

BACKGROUND: Although seasonal affective disorder and premenstrual syndrome (PMS) are frequently observed in mood disorders, little is known as to whether lifetime traits of seasonality and premenstrual distress are related to bipolar disorder independent of mood episodes. This study aimed at investigating these two cyclic traits with respect to bipolar I and II disorders as well as evaluating the association between them. METHODS: Subjects included 61 female patients with bipolar I or II disorders and 122 healthy women. Seasonality and premenstrual symptoms were measured retrospectively on a lifetime basis using the Seasonal Pattern Assessment Questionnaire (SPAQ) and the Premenstrual Symptoms Screening Tool (PSST). RESULTS: Patients showed higher global seasonality scores on the SPAQ compared to the normal controls. Further, the patient-control difference was more prominent in cases of bipolar II disorder (p<0.0001) than in bipolar I disorder (p=0.001). The prevalence of moderate to severe PMS as indicated on the PSST was also significantly higher in bipolar II disorder patients (51.6%) as compared to controls (19.7%). A significant association between seasonality and PMS was observed in both patient and control groups. CONCLUSIONS: The results suggested that female patients with bipolar disorder experience seasonal and premenstrual changes in mood and behavior regardless of their mood episodes, and traits of seasonality and PMS are associated with each other. A common biological mechanism of these two cyclic conditions may be involved in the development of the cyclicity of bipolar disorder.