Vitamin B6 is associated with depressive symptomatology in Massachusetts elders.

OBJECTIVE: We examined the cross-sectional relationship between dietary vitamin B6 and plasma pyridoxyl-5'-phosphate concentrations (PLP) with depressive symptomatology among a representative sample of 618 elderly Caribbean Hispanics, and a neighborhood based comparison group of 251 non-Hispanic white (NHW) older adults in Massachusetts. METHODS: Depressive symptomatology was assessed with the Center for Epidemiologic Studies Depression Scale (CES-D). 41% of Hispanics and 22.6% of NHWs had CES-D scores greater than 16, indicating depressive caseness. Dietary intake was calculated from a semi-quantitative food frequency questionnaire (FFQ) designed for this population. RESULTS: PLP was significantly associated with CES-D score and depressive caseness in the total sample and in non-supplement users. Deficient levels of plasma PLP (plasma PLP < 20 nmol/L) approximately doubled the likelihood of depressive caseness. Total intake (diet + supplement) of vitamin B(6) was not associated with these outcomes. However, dietary vitamin B(6) was significantly associated with CES-D score and depressive caseness. CONCLUSION: Longitudinal studies are needed to clarify the direction of causality between vitamin B6 and depressive symptoms.

Recruitment of minority and underserved populations in the United States: the Centers for Population Health and Health Disparities experience.

OBJECTIVE: The recruitment of minority and underserved individuals to research studies is often problematic. The purpose of this study was to describe the recruitment experiences of projects that actively recruited minority and underserved populations as part of The Centers for Population Health and Health Disparities (CPHHD) initiative. METHODS: Principal investigators and research staff from 17 research projects at eight institutions across the United States were surveyed about their recruitment experiences. Investigators reported the study purpose and design, recruitment methods employed, recruitment progress, problems or challenges to recruitment, strategies used to address these problems, and difficulties resulting from Institutional Review Board (IRB) or Health Insurance Portability and Accountability Act of 1996 (HIPAA) requirements. Additionally, information was collected about participant burden and compensation. Burden was classified on a three-level scale. Recruitment results were reported as of March 31, 2007. RESULTS: Recruitment attainment ranged from 52% to 184% of the participant recruitment goals. Commonly reported recruitment problems included administrative issues, and difficulties with establishing community partnerships and contacting potential participants. Long study questionnaires, extended follow-up, and narrow eligibility criteria were also problematic. The majority of projects reported difficulties with IRB approvals, though few reported issues related to HIPAA requirements. Attempted solutions to recruitment problems varied across Centers and included using multiple recruitment sites and sources and culturally appropriate invitations to participate. Participant burden and compensation varied widely across the projects, however, accrual appeared to be inversely associated with the amount of participant burden for each project. CONCLUSION: Recruitment of minority and underserved populations to clinical trials is necessary to increase study generalizbility and reduce health disparities. Our results demonstrate the importance of flexible study designs which allow adaptation to recruitment challenges. These experiences also highlight the importance of involving community members and reducing participant burden to achieve success in recruiting individuals from minority and underserved populations.