Childhood socioeconomic status and adult femoral neck bone strength: findings from the Midlife in the United States Study

Childhood Family Environment and Osteoporosis in a Population-Based Cohort Study of Middle-to Older-Age Americans

Demographic and early-life socioeconomic and parental investment factors may influence later-life health and development of chronic and progressive diseases, including osteoporosis, a costly condition common among women. The "long arm of childhood" literature links negative early-life exposures to lower socioeconomic attainment and worse adult health. We build on a small literature linking childhood socioeconomic status (SES) and bone health, providing evidence of whether associations exist between lower childhood SES and maternal investment and higher risk of osteoporosis diagnosis. We further examine whether persons identifying with non-White racial/ethnic groups experience underdiagnosis. Data from the nationally representative, population-based cohort Health and Retirement Study (N = 5,490-11,819) were analyzed for participants ages 50-90 to assess these relationships. Using a machine learning algorithm, we estimated seven survey-weighted logit models. Greater maternal investment was linked to lower odds of osteoporosis diagnosis (odds ratio [OR] = 0.80, 95% confidence interval [CI] = 0.69, 0.92), but childhood SES was not (OR = 1.03, 95% CI = 0.94, 1.13). Identifying as Black/African American (OR = 0.56, 95% CI = 0.40, 0.80) was associated with lower odds, and identifying as female (OR = 7.22, 95% CI = 5.54, 9.40) produced higher odds of diagnosis. There were differences in diagnosis across intersectional racial/ethnic and sex identities, after accounting for having a bone density scan, and a model predicting bone density scan receipt demonstrated unequal screening across groups. Greater maternal investment was linked to lower odds of osteoporosis diagnosis, likely reflecting links to life-course accumulation of human capital and childhood nutrition. There is some evidence of underdiagnosis related to bone density scan access. Yet results demonstrated a limited role for the long arm of childhood in later-life osteoporosis diagnosis. Findings suggest that (1) clinicians should consider life-course context when assessing osteoporosis risk and (2) diversity, equity, and inclusivity training for clinicians could improve health equity. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Structural Inequity and Socioeconomic Status Link to Osteoporosis Diagnosis in a Population-Based Cohort of Middle-Older-Age Americans

Socioeconomic status (SES) is an important social determinant of health inequities that has been linked to chronic conditions, including osteoporosis, but research tends to focus on socioeconomic disadvantage rather than how socioeconomic advantage may facilitate these inequities. This study accounts for structural inequities and assesses the relationship between early-life and later-life SES, and risk of osteoporosis diagnosis. Data come from the nationally representative, population-based cohort Health and Retirement Study and include individuals ages 50 to 90. The outcome variable is osteoporosis diagnosis. Logistic regression models of the relationship between SES and osteoporosis diagnosis are estimated, accounting for demographic, health, and childhood variables. Higher levels of childhood and adult SES link to lower odds of osteoporosis diagnosis. Structural inequities in income and underdiagnosis of osteoporosis among persons identifying as Black/African American were detected. Accounting for bone density scan access, inequities in osteoporosis diagnosis appear to stem from barriers to accessing health care due to financial constraints. The important role of SES and evidence of structural inequities leading to underdiagnosis suggest the critical importance of clinicians receiving Diversity, Equity, and Inclusion training to reduce health inequities.

Retrospective reports of socioeconomic disadvantage in childhood and mortality risk: are associations consistent across measures and sex?

Although prior research has established associations between childhood socioeconomic disadvantage and all-cause mortality, there is still limited research investigating (1) the consistency between subjective and objective reports of childhood socioeconomic status, (2) sex differences in the associations between childhood socioeconomic disadvantage and all-cause mortality, and (3) potential mediators within these associations. Drawing on data from the Midlife in the United States (MIDUS) cohort (N = 7425), we examined the associations between three distinct indicators of childhood socioeconomic disadvantage and all-cause mortality risk, and whether these associations differ for males and females. Among males only, lower perceived relative childhood financial status, lower levels of parents' education, and receipt of welfare during childhood were associated with excess mortality risk, adjusted for age and minority status, with adjusted hazard ratios ranging from 1.24 (95% confidence interval (CI): 1.02, 1.51) for perceived childhood financial status to 1.28 (95% CI: 1.11, 1.47) for welfare in childhood. When additionally adjusted for education, substance use, depression, and underlying health conditions, only childhood welfare status maintained an association with mortality (AHR, 1.17; 95% CI, 1.02-1.35). Mediation analyses among males revealed that education, substance use, depression, and underlying health conditions accounted for substantial proportions of these associations, ranging from 31.03 to 57.63%, across indicators of childhood socioeconomic disadvantage. Future research is needed to clarify the developmental mechanisms that lead to sex differences and identify effective strategies to intervene on the relation between childhood socioeconomic position and excess mortality risk among males.

Factors influencing peak bone mass gain

Bone mass is a key determinant of osteoporosis and fragility fractures. Epidemiologic studies have shown that a 10% increase in peak bone mass (PBM) at the population level reduces the risk of fracture later in life by 50%. Low PBM is possibly due to the bone loss caused by various conditions or processes that occur during adolescence and young adulthood. Race, gender, and family history (genetics) are responsible for the majority of PBM, but other factors, such as physical activity, calcium and vitamin D intake, weight, smoking and alcohol consumption, socioeconomic status, age at menarche, and other secondary causes (diseases and medications), play important roles in PBM gain during childhood and adolescence. Hence, the optimization of lifestyle factors that affect PBM and bone strength is an important strategy to maximize PBM among adolescents and young people, and thus to reduce the low bone mass or osteoporosis risk in later life. This review aims to summarize the available evidence for the common but important factors that influence bone mass gain during growth and development and discuss the advances of developing high PBM.

Secular decline in limb bone strength among South African Africans during the 19th and 20th centuries

OBJECTIVES

South African Africans have been reported to have experienced negative or null secular trends in stature and other measures of skeletal structure across the 19th and 20th centuries, presumably due to poor living conditions during a time of intensifying racial discrimination. Here, we investigate whether any secular trend is apparent in limb bone strength during the same period.

MATERIALS AND METHODS

Cadaver-derived skeletons (n = 221) were analyzed from female and male South African Africans who were born between 1839 and 1970, lived in and around Johannesburg, and died between 1925 and 1991 when they were 17-90 years of age. For each skeleton, a humerus and femur were scanned using computed tomography, and mid-diaphyseal cross-sectional geometric properties were calculated and scaled according to body size.

RESULTS

In general linear mixed models accounting for sex, age at death, and skeletal element, year of birth was a significant (p < .05) negative predictor of size-standardized mid-diaphyseal cortical area (a proxy for resistance to axial loading) and polar moment of area (a proxy for resistance to bending and torsion), indicating a temporal trend toward diminishing limb bone strength. No significant interactions were detected between year of birth and age at death, suggesting that the decline in limb bone strength was mainly due to changes in skeletal maturation rather than severity of age-related bone loss.

DISCUSSION

Limb bone strength is thus potentially another feature of the skeletal biology of South African Africans that was compromised by poor living conditions during the 19th and 20th centuries.

Childhood Exposure to Passive Smoking and Bone Health in Adulthood: The Cardiovascular Risk in Young Finns Study

CONTEXT

Passive smoke exposure has been linked to the risk of osteoporosis in adults.

OBJECTIVE

We examined the independent effects of childhood passive smoke exposure on adult bone health.

DESIGN/SETTING

Longitudinal, the Cardiovascular Risk in Young Finns Study.

PARTICIPANTS

The study cohort included 1422 individuals followed for 28 years since baseline in 1980 (age 3 to 18 years). Exposure to passive smoking was determined in childhood. In adulthood, peripheral bone traits were assessed with peripheral quantitative CT (pQCT) at the tibia and radius, and calcaneal mineral density was estimated with quantitative ultrasound. Fracture data were gathered by questionnaires.

RESULTS

Parental smoking in childhood was associated with lower pQCT-derived bone sum index in adulthood (β± SE, -0.064 ± 0.023 per smoking parent; P = 0.004) in multivariate models adjusted for age, sex, active smoking, body mass index, serum 25-OH vitamin D concentration, physical activity, and parental socioeconomic position. Similarly, parental smoking was associated with lower heel ultrasound estimated bone mineral density in adulthood (β± SE, -0.097 ± 0.041 per smoking parent; P = 0.02). Parental smoking was also associated with the incidence of low-energy fractures (OR, 1.28; 95% CI, 1.01 to 1.62). Individuals with elevated cotinine levels (3 to 20 ng/mL) in childhood had lower bone sum index with pQCT (β± SE, -0.206 ± 0.057; P = 0.0003). Children whose parents smoked and had high cotinine levels (3 to 20 ng/mL) had significantly lower pQCT-derived bone sum index compared with those with smoking parents but had low cotinine levels (<3 ng/mL) (β± SE, -0.192 ± 0.072; P = 0.008).

CONCLUSIONS AND RELEVANCE

Children of parents who smoke have evidence of impaired bone health in adulthood.

Accelerated Aging: The Role of Socioeconomic, Social, Demographic, and Biological Factors on Bone Mineral Density

We investigate socioeconomic, social, demographic, and biological variables that are associated with chronic stress in the body to assess whether they have an effect on bone mineral density (BMD) as an indicator of accelerated aging. Multiple regression models were derived from data in the Midlife in the United States: A National Longitudinal Study of Health and Well-Being, Waves 1 (1995–1996) and 2 (2004–2006). Three BMD variables were used as outcomes: femoral, femoral neck, and spine T scores. The sample included 333 men and women aged 34–80. Poverty and C-reactive protein were related to BMD for spine T scores, partially consistent with hypotheses. But, marital status, perceived support of a partner, and education were not associated. Friend strain was discovered to have a relationship with BMD. More variables, and from a broader context, need to be examined together to understand what affects reduced BMD, given the high costs of accelerated aging.

Childhood Socioeconomic Disadvantage, Occupational, Leisure-Time, and Household Physical Activity, and Diabetes in Adulthood

BACKGROUND

Regular physical activity is a key way to prevent disease. However, we have a limited understanding of the socioeconomic precursors and glucoregulatory sequelae of engaging in physical activity in different domains.

METHODS

We examined the associations among life course socioeconomic disadvantage; meeting the physical activity guidelines with leisure-time physical activity, occupational physical activity, or household physical activity; and prediabetes and diabetes in the Midlife in the United States national study (N = 986).

RESULTS

Childhood disadvantage was associated with lower odds of meeting the guidelines with leisure-time physical activity (odds ratio = 0.75; 95% confidence interval, 0.65-0.86). Adulthood disadvantage was associated with higher odds of meeting the guidelines with occupational physical activity (odds ratio = 1.94; 95% confidence interval, 1.49-2.53). Importantly, while meeting the guidelines with leisure-time physical activity was associated with lower odds of prediabetes and diabetes, we found no evidence for associations among occupational physical activity, household physical activity, and glucoregulation.

CONCLUSION

Current US physical activity guidelines do not differentiate between physical activity for leisure or work, assuming that physical activity in any domain confers comparable health benefits. We documented important differences in the associations among lifetime socioeconomic disadvantage, physical activity domain, and diabetes, suggesting that physical activity domain potentially belongs in the guidelines, similar to other characteristics of activity (eg, type, intensity).

Emotional and instrumental support during childhood and biological dysregulation in midlife

OBJECTIVE

To determine whether greater emotional and instrumental support during childhood is associated with less dysregulation across multiple physiological systems in midlife.

METHODS

Data are from participants in the second wave of the Midlife in the United States study (2004-2005) who participated in a clinic-based assessment of health status. Emotional and instrumental support was measured using a seven-item scale (α=0.89) based on participant retrospective self-report. Biological dysregulation was assessed using an allostatic load (AL) score constructed from 24 measures across seven physiological systems (N=1236, aged 34-84 years).

RESULTS

Emotional and instrumental support in childhood was associated with lower AL in a monotonic fashion: compared to individuals in the lowest quartile of support, respondents in the second, third, and fourth quartiles had -0.08 (standard deviation (SD)=0.08), -0.13 (SD=0.08) and -0.21 (SD=0.08) units lower AL, adjusting for age, sex, and race. This pattern was maintained after adjustment for reporting bias, childhood socioeconomic disadvantage, past-year depression, and physician-diagnosed cardiovascular disease or diabetes (p≤0.01). The inflammation and metabolic-lipid subscales showed the strongest associations.

CONCLUSIONS

Greater emotional and instrumental support in childhood was associated with less biological dysregulation in midlife, even after accounting for socioeconomic disadvantage in childhood and other potential confounders.

Adult bone strength of children from single-parent families: the Midlife in the United States Study

Bone health may be negatively impacted by childhood socio-environmental circumstances. We examined the independent associations of single-parent childhood and parental death or divorce in childhood with adult bone strength indices. Longer exposure to a single-parent household in childhood was associated with lower bone strength in adulthood.

INTRODUCTION

Because peak bone mass is acquired during childhood, bone health may be negatively impacted by childhood socio-environmental disadvantage. The goal of this study was to determine whether being raised in a single-parent household is associated with lower bone strength in adulthood.

METHODS

Using dual-energy X-ray absorptiometry data from 708 participants (mean age 57 years) in the Midlife in the United States Biomarker Project, we examined the independent associations of composite indices of femoral neck bone strength relative to load (in three failure modes: compression, bending, and impact) in adulthood with the experience of single-parent childhood and parental death or divorce in childhood.

RESULTS

After adjustment for gender, race, menopause transition stage, age, and body mass index, each additional year of single-parent childhood was associated with 0.02 to 0.03 SD lower indices of adult femoral neck strength. In those with 9-16 years of single-parent childhood, the compression strength index was 0.41 SD lower, bending strength index was 0.31 SD lower, and impact strength index was 0.25 SD lower (all p values < 0.05). In contrast, parental death or divorce during childhood was not by itself independently associated with adult bone strength indices. The magnitudes of these associations were unaltered by additional adjustment for lifestyle factors and socioeconomic status in childhood and adulthood.

CONCLUSIONS

Independent of parental death or divorce, growing up in a single-parent household is associated with lower femoral neck bone strength in adulthood, and this association is not entirely explained by childhood or adult socioeconomic conditions or lifestyle choices.

Childhood socioeconomic disadvantage and prediabetes and diabetes in later life: a study of biopsychosocial pathways

OBJECTIVE

We examined the relationship between childhood socioeconomic status (SES) and glucoregulation in later life and used a life-course framework to examine critical periods and underlying pathways.

METHODS

Data came from the Midlife in the US (MIDUS) national study (n = 895). Childhood SES indicators retrospectively reported at MIDUS I were used to create a childhood SES disadvantage index. Adult SES disadvantage and potential pathways were measured at MIDUS I and included waist circumference, depressive symptoms, and physical activity. Glucose and hemoglobin A1c, measured approximately 9 to 10 years later at MIDUS II, were used to create the ordinal outcome measure (no diabetes/prediabetes/diabetes).

RESULTS

Childhood SES disadvantage predicted increased odds of prediabetes and diabetes net of age, sex, race, and smoking (odds ratio = 1.11, 95% confidence interval = 1.01-1.22). Childhood SES disadvantage predicted adult SES disadvantage (β = .26, p = .001) and the three key mediators: waist circumference (β = 0.10, p = .002), physical activity (β = -0.11, p = .001), and depressive symptoms (β = 0.07, p = .072). When childhood and adult SES disadvantage were in the same model, only adult SES predicted glucoregulation (odds ratio = 1.07, 95% confidence interval = 1.01-1.13). The SES disadvantage measures were no longer significantly associated with glucoregulation after including waist circumference, physical activity, and depressive symptoms, all of which were significant predictors of glucoregulation.

CONCLUSIONS

The consequences of childhood SES disadvantage are complex and include both critical period and pathway effects. The lack of a direct effect of childhood SES on glucoregulation does not negate the importance of early environment but suggests that early-life socioeconomic factors propel unequal life-course trajectories that ultimately influence health.

Multisystem dysregulation and bone strength: findings from the study of midlife in the United States

CONTEXT

Accumulated dysregulation across multiple physiological systems, or allostatic load (AL), has been proposed as the biological pathway from psychosocial adversity to poor health.

OBJECTIVE

The objective of the study was to examine whether AL, constructed using biomarkers and medication data from seven systems (sympathetic, parasympathetic, hypothalamic-pituitary-adrenal axis, cardiovascular regulation, inflammation, and lipid and glucose metabolism), is associated with lower bone strength in a national sample.

DESIGN

This was a cross-sectional study.

SETTING AND PARTICIPANTS

Seven hundred three community-dwelling men and women from the Study of Midlife in the United States participated in the study.

OUTCOME MEASURES

Bone mineral density (BMD) was measured in the femoral neck and lumbar spine. Femoral neck BMD was combined with bone size and body size to create composite indices of femoral neck strength relative to load in three failure modes: compression, bending, and impact.

RESULTS

In mixed-effects linear regression controlling for clustering within families and adjusted for age, gender, race/ethnicity, body mass index, menopausal transition stage, childhood socioeconomic status, adult finances, education level, and study center, each SD increment in AL score was associated with between 0.10 and 0.11 SD decrements in lumbar spine BMD and each of the three composite strength indices (all values of P < .05). Gender modified the association of AL only with femoral neck BMD; each SD increment in AL score was associated with 0.21 SD decrement in femoral neck BMD in men (P < .01) but not in women.

CONCLUSIONS

Accumulation of dysregulation across systems was modestly associated with lower bone strength. This study adds to the accumulating evidence that multisystem dysregulation, or AL, predicts a variety of adverse health outcomes.

Marital histories, marital support, and bone density: findings from the Midlife in the United States Study

We examined the association between marital life history and bone mineral density (BMD) in a national sample from the US. In men, being stably married was independently associated with better lumbar spine BMD, and in women, more spousal support was associated with better lumbar spine BMD.

INTRODUCTION

Adult bone mass may be influenced by stressors over the life course. We examined the association between marital life history and bone mineral density (BMD) net socioeconomic and behavioral factors known to influence bone mass. We sought evidence for a gender difference in the association between marital history and adult BMD.

METHODS

We used data from 632 adult participants in the Midlife in the United States Study to examine associations between marital history and BMD, stratified by gender, and adjusted for age, weight, menopausal stage, medication use, childhood socioeconomic advantage, adult financial status, education, physical activity, smoking, and alcohol consumption.

RESULTS

Compared to stably married men, men who were currently divorced, widowed, or separated, men who were currently married but previously divorced, widowed, or separated, and never married men had 0.33 (95% CI: 0.01, 0.65), 0.36 (95% CI: 0.10, 0.83), and 0.53 (95% CI: 0.23, 0.83) standard deviations lower lumbar spine BMD, respectively. Among men married at least once, every year decrement in age at first marriage (under age 25) was associated with 0.07 SD decrement in lumbar spine BMD (95% CI: 0.002, 0.13). In women, greater support from the spouse was associated with higher lumbar spine BMD.

CONCLUSIONS

Our findings suggest that marriage before age 25 and marital disruptions are deleterious to bone health in men, and that marital quality is associated with better bone health in women.