Objectives: This study investigates direct and indirect influences of childhood social, behavioral, and health exposures on later-life osteoarthritis and rheumatoid arthritis development. Methods: Drawing from cumulative inequality theory and six waves of the Health and Retirement Study (2004–2014), we estimate structural equation modeling-based discrete-time survival analysis of the association between six childhood exposure domains and both osteoarthritis and rheumatoid arthritis incidence for men (n = 2720) and women (n = 2974). Using the delta method to test for mediation, we examine indirect effects via selected health-related risks and resources. Results: Risky adolescent behavior is associated with rheumatoid arthritis incidence for women (h.O.R. = 1.883, 95% C.I. [1.016, 3.490]), whereas several types of childhood exposures are associated with later-life osteoarthritis development for both men and women. Experiencing two or more childhood socioeconomic disadvantages is indirectly associated with osteoarthritis (men: coef. = 0.024, 95% C.I. [0.003, 0.045]; women: coef. = 0.111, 95% C.I. [0.071, 0.150]) and rheumatoid arthritis (men: coef. = 0.037, 95% C.I. [0.000, 0.074]; women: coef. = 0.097, 95% C.I. [0.035, 0.159]) development through adult body mass index. Discussion: Findings highlight the importance of childhood contexts in understanding the development of later-life osteoarthritis and rheumatoid arthritis.
Over the past few decades, arthritis prevalence has grown to include nearly half of adults aged 65 and over (Barbour et al., 2017). Arthritis presents tremendous personal, social, and economic costs that are projected to worsen in our aging society (Hootman et al., 2016). As a common co-morbid condition, arthritis creates barriers to physical activity and raises the risk of disability and complications associated with heart disease and diabetes (Centers for Disease Control and Prevention [CDC], 2009; Peek & Coward, 2000). In terms of economic burden, it was estimated in 2013 that the combined earnings losses and medical expenses due to arthritis was $303.5 billion—about 1% of the US gross domestic product (Murphy et al., 2017).
Arthritis is characterized by painful inflammation in joints. There are different forms of the disease with the most prevalent types being osteoarthritis, which is a multifactorial degenerative disease that often occurs later in life (Glyn-Jones et al., 2015), and rheumatoid arthritis, which is a systemic, autoimmune disease that can occur at any age though it commonly develops in later life (Alpízar-Rodríguez & Finckh, 2017). Although specific causes are not well understood, risk factors common to both osteoarthritis and rheumatoid arthritis such as obesity and genetics have been identified along with greater prevalence among women (Alpízar-Rodríguez & Finckh, 2017; Glyn-Jones et al., 2015). Despite similarities between osteoarthritis and rheumatoid arthritis, their development and progression are substantially different. Risk factors specific to osteoarthritis include joint injury and trauma (Glyn-Jones et al., 2015), and those specific to rheumatoid arthritis include infection, smoking, and some nutritional factors such as high sodium intake and occupational exposure to chemicals (Alpízar-Rodríguez & Finckh, 2017).
Theoretical advancements, empirical evidence, and the widespread push towards prevention and early detection have built a convincing case for considering early-life exposures as antecedents of disease development. Indeed, evidence suggests that early-life events and experiences such as abuse and parental addictions are associated with adult arthritis (Fuller-Thomson et al., 2009; Spitzer et al., 2013). However, the current literature is limited in several ways as pointed out by a recent scoping review; studies often fail to distinguish between different types of arthritis and do not examine social pathways by which early-life exposures may be related to adult arthritis development (Schwetlik et al., 2021).
Given differences in the etiology and pathogenesis by arthritis type, it is possible that some types of childhood events and experiences (e.g., abuse and socioeconomic disadvantage) are associated with adult risk factors specific to osteoarthritis and/or rheumatoid arthritis, highlighting unique social pathways in the development of these diseases. Moreover, studies that do not examine arthritis types according to pathophysiology could give rise to misleading conclusions and misinformed interventions. To address these limitations, this study uses a nationally representative sample of adults over the age of 50 to investigate the direct and indirect associations between several types of childhood exposure domains (i.e., socioeconomic disadvantage, risky parental behavior, infectious disease, chronic diseases, impairments, and risky adolescent behavior) and the incidence of osteoarthritis and rheumatoid arthritis among men and women in later life. In addition, we examine potential social/behavioral and health pathways that have been linked to childhood exposures and represent risk factors for osteoarthritis and/or rheumatoid arthritis (e.g., body mass index (BMI) and smoking).
This study was published in Research on Aging.