Cohort Trends in the Burden of Multiple Chronic Conditions Among Aging U.S. Adults

Abstract

Objectives: Multimorbidity, also referred to as multiple chronic conditions (MCCs), is the concurrent presence of 2 or more chronic health conditions. Increasing multimorbidity represents a substantial threat to the health of aging populations. Recent trends suggest greater risk of poor health and mortality among later-born cohorts, yet we are unaware of work examining cohort differences in multimorbidity among aging U.S. adults.

Methods: We examine intercohort variation in MCC burden in adults aged 51 years and older using 20 years (n = 33,598; 1998-2018) of repeated assessment drawn from the Health and Retirement Study. The index of MCCs included 9 chronic conditions (heart disease, hypertension, stroke, diabetes, arthritis, lung disease, cancer excluding skin cancer, high depressive symptoms, and cognitive impairment). We used linear mixed models with various approaches to estimate age/period/cohort effects to model intercohort patterns in MCC burden. We also explored variation in the specific conditions driving cohort differences in multimorbidity.

Results: More recent cohorts had greater MCC burden and developed multimorbidity at earlier ages than those born to prior generations. The burden of chronic conditions was patterned by life-course sociodemographic factors and childhood health for all cohorts. Among adults with multimorbidity, arthritis and hypertension were the most prevalent conditions for all cohorts, and there was evidence that high depressive symptoms and diabetes contributed to the observed cohort differences in multimorbidity risk.

Discussion: Our results suggest increasing multimorbidity burden among more recently born cohorts of aging U.S. adults and should inform policy to address diminishing health in aging populations.

Keywords: Baby Boom cohort; Health and Retirement Study; Life course; Multimorbidity; Population aging.

Figure 1.

Observed and estimated trajectories of multiple chronic conditions (MCCs) by age and cohort, HRS 1998–2018. Notes: GG = Greatest Generation (born 1903–1923); ECOD = Early Children of Depression (born 1924–1930); LCOD = Late Children of Depression (born 1931–1941); WB = War Babies (born 1942–1947); EBB = Early Baby Boomers (born 1948–1953); MBB = Mid Baby Boomers (born 1954–1959); LBB = Late Baby Boomers (born 1960–1965). Panel A: Weighted means of MCC burden by cohort and age group. Panel B: Estimates of MCC burden by cohort and age group from Model 1 (fixed effects: cohort, linear age, quadratic age, covariates; no period effect). Panel C: Estimates of MCC burden by cohort and age group from Model 2 (fixed effects: cohort, linear age, quadratic age, covariates; random period effect). Panel D: Estimates of MCC burden by cohort and age group from Model 3 (fixed effects: cohort, linear age, quadratic age, cohort × linear age interaction terms, covariates; random period effect). Survey weights from respondent’s first available interview were used to adjust observed and estimated trajectories. HRS = Health and Retirement Study.

Figure 2.

Estimated trajectory of multiple chronic conditions (MCCs) by interview wave, HRS 1998–2018. Notes: Statistical model used to generate estimates included fixed effects for wave, linear age, quadratic age, and covariates; no cohort effect estimated. Survey weights from respondent’s first available interview were used to adjust estimated trajectory. HRS = Health and Retirement Study.