Midlife in the United States (MIDUS 2): Biomarker Project, 2004-2009

The Biomarker study is Project 4 of the MIDUS longitudinal study, a national survey of more than 7,000 Americans (aged 25 to 74) begun in 1994. The purpose of the larger study was to investigate the role of behavioral, psychological, and social factors in understanding age-related differences in physical and mental health. With support from the National Institute on Aging, a longitudinal follow-up of the original MIDUS samples [core sample (N = 3,487), metropolitan over-samples (N = 757), twins (N = 957 pairs), and siblings (N = 950)] was conducted in 2004-2006. Guiding hypotheses, at the most general level, were that behavioral and psychosocial factors are consequential for health (physical and mental). A description of the study and findings from it are available on the MIDUS Web site. The Biomarker Project (Project 4) of MIDUS II contains data from 1,255 respondents. These respondents include two distinct subsamples, all of whom completed the Project 1 Survey: (1) longitudinal survey sample (n = 1,054) and (2) Milwaukee sample (n = 201). The Milwaukee group contained individuals who participated in the baseline MIDUS Milwaukee study, initiated in 2005. The purpose of the Biomarker Project (Project 4) was to add comprehensive biological assessments on a subsample of MIDUS respondents, thus facilitating analyses that integrate behavioral and psychosocial factors with biology. The broad aim is to identify biopsychosocial pathways that contribute to diverse health outcomes. A further theme is to investigate protective roles that behavioral and psychosocial factors have in delaying morbidity and mortality, or in fostering resilience and recovery from health challenges once they occur. The research was not disease-specific, given that psychosocial factors have relevance across multiple health endpoints. Biomarker data collection was carried out at three General Clinical Research Centers (at UCLA, University of Wisconsin, and Georgetown University). The biomarkers reflect functioning of the hypothalamic-pituitary-adrenal axis, the autonomic nervous system, the immune system, cardiovascular system, musculoskeletal system, antioxidants, and metabolic processes. Our specimens (fasting blood draw, 12-hour urine, saliva) allow for assessment of multiple indicators within these major systems. The protocol also included assessments by clinicians or trained staff, including vital signs, morphology, functional capacities, bone densitometry, medication usage, and a physical exam. Project staff obtained indicators of heart-rate variability, beat to beat blood pressure, respiration, and salivary cortisol assessments during an experimental protocol that included both a cognitive and orthostatic challenge. Finally, to augment the self-reported data collected in Project 1, participants completed a medical history, self-administered questionnaire, and self-reported sleep assessments. For respondents at one site (UW-Madison), objective sleep assessments were also obtained with an Actiwatch(R) activity monitor.

生物标志物研究是MIDUS纵向研究的第4个项目，该研究始于1994年，是一项针对超过7,000名美国成年人（年龄在25至74岁之间）的国家调查。更大规模研究的目的是探究行为、心理和社会因素在理解与年龄相关的身心健康差异中的作用。在国家老龄化研究所的支持下，对原始MIDUS样本（核心样本[N=3,487]、都市过度样本[N=757]、双胞胎[N=957对]和兄弟姐妹[N=950]）进行了1994-2006年的纵向追踪研究。在最一般层面上，指导性假设是行为和心理社会因素对健康（包括生理和心理健康）具有重大影响。关于该研究及其发现，可在MIDUS网站上查阅。MIDUS II的生物标志物项目（项目4）包含1,255名受访者的数据。这些受访者包括两个不同的子样本，他们均完成了项目1调查：（1）纵向调查样本（n=1,054）和（2）密尔沃基样本（n=201）。密尔沃基小组包括那些自2005年起参与MIDUS密尔沃基基准研究的个体。生物标志物项目（项目4）的目的是在MIDUS受访者中增加全面的生物评估，从而促进将行为和心理社会因素与生物学因素整合的分析。其宏观目标是识别有助于多种健康结果的生物心理社会途径。另一个主题是研究行为和心理社会因素在延缓疾病和死亡发生、或是在健康挑战发生后促进恢复和适应所起的保护作用。鉴于心理社会因素在多个健康终点上的相关性，该研究并未针对特定疾病。生物标志物数据收集在三个通用临床研究中心（加州大学洛杉矶分校、威斯康星大学和乔治城大学）进行。生物标志物反映了下丘脑-垂体-肾上腺轴、自主神经系统、免疫系统、心血管系统、骨骼肌肉系统、抗氧化剂和代谢过程的功能。我们的样本（空腹血液采集、12小时尿液、唾液）允许对主要系统中的多个指标进行评估。研究方案还包括临床医生或受过培训的员工进行的评估，包括生命体征、形态学、功能能力、骨密度测量、药物使用和体格检查。项目工作人员在包括认知和直立挑战的实验方案中获得了心率变异性、血压波动、呼吸和唾液皮质醇评估的指标。最后，为了补充项目1中收集的自我报告数据，参与者完成了病历、自我管理问卷和自我报告的睡眠评估。对于位于一个地点（威斯康星大学麦迪逊分校）的受访者，还使用了Actiwatch(R)活动监测器进行了客观睡眠评估。