Table 2.

Measurement of Healthspan-Related Characteristics and Mortality, Health and Retirement Study, 1992–2018

Outcome Measure	No. of Participants		Description
	VBS   Sample	VBS DNAm   Sample
Functional impairment	3,621	1,596	Functional impairments were measured from tests of lung function (peak expiratory flow), grip strength, gait speed, and balance. The tests are described in detail in Web Table 1. We classified test scores at the 30th percentile of the HRS distribution or lower as indicating functional impairment. Percentiles for grip strength were calculated separately for men and women. We calculated numbers of functional impairments for participants providing data on at least 3 of the 4 tests. Counts were winsorized at a value of 3 (HRS VBS sample: mean = 1.13 (SD, 1.08); VBS DNAm sample: mean = 1.17 (SD, 1.09)).
No. of ADL limitations	8,198	3,598	Participants were asked whether they had difficulty performing 6 ADLs: dressing, eating (such as cutting up one’s food), bathing and showering, getting into and out of bed, using the toilet, and walking across a room. We summed the number of activities for which participants reported having difficulty and coded the resulting ADL score as 0, 1, 2, or ≥3 ADL limitations (VBS sample: mean = 0.30 (SD, 0.75); VBS DNAm sample: mean = 0.31 (SD, 0.78)). For longitudinal analysis, we counted any new ADL difficulties reported at the HRS 2018 assessment (VBS sample: mean = 0.19 (SD, 0.65); VBS DNAm sample: mean = 0.20 (SD, 0.67)).
Chronic conditions	8,196	3,597	Chronic disease diagnoses were ascertained from participants’ reports about whether a physician had ever diagnosed them with hypertension, type 2 diabetes, cancer (excluding minor skin cancer), chronic lung disease, heart problems (heart attack, coronary heart disease, angina, congestive heart failure), and/or stroke. Counts of chronic disease diagnoses were winsorized at a value of 3 (VBS sample: mean = 1.45 (SD, 1.04); VBS DNAm sample: mean = 1.48 (SD, 1.04)). For longitudinal analysis, we counted any new diagnoses reported at the 2018 HRS assessment (VBS sample: mean = 0.14 (SD, 0.39); VBS DNAm sample: mean = 0.15 (SD, 0.39)).
Self-rated health	8,191	3,595	Participants were asked to rate their own health on a scale of 1 to 5 (1 = excellent, 5 = poor; VBS sample: mean = 2.88 (SD, 1.03); DNAm sample: mean = 2.89 (SD, 1.03)). For longitudinal analysis, we calculated the difference in self-rated health between waves by subtracting the HRS 2016-wave rating from the 2018-wave rating (possible range, −4 to 4; VBS sample: mean = 0.04 (SD, 0.82); VBS DNAm sample: mean = 0.04 (SD, 0.81)).
Mortality	8,198	3,598	Mortality follow-up was conducted through 2019. During follow-up, 237 deaths were recorded in the full VBS sample, of which 123 were recorded for participants in the VBS DNAm sample.

Abbreviations: ADLs, activities of daily living; DNAm, DNA methylation; HRS, Health and Retirement Study; SD, standard deviation; VBS, Venous Blood Study.