Reproductive history, socioeconomic status, and self-reported health status of women aged 50 years or older

A study of the effect of number of children on depression among rural older women: empirical evidence from China

The association between early reproductive events and health status in later life has always been of interest across disciplines. The purpose of this study was to investigate whether there was an association between the number of children born in the early years of elderly women and their depression in later life based on a sample of older women aged 65 years and above with at least one child in rural China. Data from the Chinese Longitudinal Healthy Longevity Survey in 2018, this study used the ordinary least square method to conduct empirical research. This study has found a significant correlation between an increase in the number of children and depression in older rural women. When considering the sex of the child, the number of daughters had a greater and more significant impact on depression. Number of children may exacerbate depression of older women through declining self-rated health and reduced social activity, while increased inter-generational support alleviated depression. The association between number of children born and depression also existed in urban older women, though not significant. Therefore, it is suggested to accelerate the improvement of supporting policies related to childbirth, developing a healthy and scientific fertility culture, and improving rural maternal and child health services. Women should be assisted in balancing their roles in the family and in society, and in particular in sharing the burden of caring for children. Targeted efforts to increase old-age protection for older people.

Less Is (Often) More: Number of Children and Health Among Older Adults in 24 Countries

OBJECTIVES

Previous evidence about the impact of parenthood on health for older adults is mixed, perhaps due to variation in number of children and context. Higher numbers of children could lead to support or strain, depending on individual and country contexts. Yet, no studies currently exist that examine associations between the number of children and several health indicators among older adults across multiple global regions.

METHODS

We analyze cross-sectional data (1992-2017) of 166,739 adults aged 50+ across 24 countries from the Health and Retirement Study family of surveys to document associations between the number of children, treated as a categorical variable, and 5 health outcomes (self-rated health, activities of daily living limitations, instrumental activities of daily living limitations, chronic conditions, and depression). We perform multivariable analyses by estimating logistic regression models for each country and each outcome.

RESULTS

Multiple comparisons between categories of number of children revealed at least 1 significant difference in each country, and a majority of significant differences indicated those with more children had poorer health. The risk of poorer health for parents of multiple children was observed in 15 countries, but in some countries, fewer children predict poorer health. The greatest number of differences was identified for depression and chronic conditions, and very few for functional limitations.

DISCUSSION

We observe a greater probability that more children are associated with poorer health in later life, especially for chronic conditions and depression. However, a universal global or regional pattern could not be identified. These findings raise new questions about how country contexts shape fertility and health.

Are pregnancy and parity associated with telomere length? A systematic review

BACKGROUND

Women's reproduction requires increased energy demands, which consequently may lead to cellular damage and aging. Hence, Telomere Length (TL), a biomarker of biological aging and health status may possibly serve as a biomarker of reproductive effort. The aim of this systematic review is to evaluate telomere dynamics throughout pregnancy and the association between parity and TL.

METHODS

A systematic search was conducted across seven databases including CINAHL, Cochrane, PsycINFO, Proquest, PubMed; Scopus; and Web of Science, using keywords and MeSH descriptors of parity and TL. Predefined inclusion and exclusion criteria were used to screen abstracts and titles. After the removal of duplicates, 3431 articles were included in the primary screening, narrowed to 194 articles included in the full-text screening. Consensus was reached for the 14 studies that were included in the final review, and the Newcastle-Ottawa scale (NOS) was utilized to assess the quality of the selected studies. A mini meta-analysis utilized JASP 0.17.3 software and included 4 applicable studies, comprising a total of 2564 participants to quantitatively assess the estimated effect size of parity on TL.

RESULTS

Of the 11 studies reviewed on parity and TL, four demonstrated a negative correlation; one - a positive correlation and six -found no correlation. Studies demonstrating a negative correlation encompassed rigorous methodological practices possibly suggesting having more children is associated with enhanced telomere attrition. Of the four longitudinal studies assessing telomere dynamics throughout pregnancy, most found no change in TL from early pregnancy to postpartum suggesting pregnancy does not affect TL from early pregnancy to early postpartum. The meta-analysis revealed a negative, yet, non-significant effect, of the estimated effect size of parity on TL(ES = -0.009, p = 0.126, CI -0.021, 0.03).

CONCLUSIONS

Studies assessing pregnancy, parity and TL yielded mixed results, most likely due to the different research methods utilized in each study. Improvements in study design to better understand the short-term effects of pregnancy on TL and the effect of parity on TL over time, include precise definitions of parity, comparisons of different age groups, inclusion of reproductive lifespan and statistically adjusting for potential confounders in the parity and TL relationship.

Life-course fertility and multimorbidity among middle-aged and elderly women in China: Evidence from China health and retirement longitudinal study

Background

Multimorbidity has become an important public health problem in China, especially among middle-aged and elderly women. Few studies have been reported on the association between multimorbidity and female fertility, which is an important stage in the life course. This study aimed to explore the association between multimorbidity and fertility history among middle-aged and elderly women in China.

Methods

Data from 10,182 middle-aged and elderly female participants in the China Health and Retirement Longitudinal Study (CHARLS) in 2018 were used in this study. Multimorbidity was defined as the presence of at least two or more chronic conditions. Logistic regression analysis, negative binomial regression analysis, and restrictive cubic splines (RCSs) were used to analyze the relationship between female fertility history and multimorbidity or the number of chronic conditions. Multivariable linear regression was used to analyze the relationship between female fertility history and multimorbidity pattern factor scores.

Results

The results of this study showed that high parity and early childbearing were significantly associated with an increased risk of multimorbidity and an increased number of chronic conditions among middle-aged and elderly women in China. Late childbearing was significantly associated with reduced risk of multimorbidity and lessened diseases. Parity and age of first childbirth were significantly correlated with the odds of multimorbidity. The association between fertility history and multimorbidity was found to be influenced by age and urban-rural dual structure. Women with high parity tend to have higher factor scores of cardiac-metabolic, visceral-arthritic, and respiratory-psychiatric patterns. Women with early childbearing tended to have higher factor scores of the visceral-arthritic pattern and those with late childbearing tended to have lower factor scores of the cardiac-metabolic pattern.

Conclusion

Fertility history has a significant effect on multimorbidity in the middle and later lives of Chinese women. This study is of great importance for reducing the prevalence of multimorbidity among Chinese women through their life course and promoting health during their middle and later lives.

Association Between Sex-Specific Risk Factors and Risk of New-Onset Atrial Fibrillation Among Women

IMPORTANCE

Atrial fibrillation (AF) is the most common cardiac arrhythmia worldwide, with different epidemiological and pathophysiological processes for women vs men and a poorer prognosis for women. Further investigation of sex-specific risk factors associated with AF development in women is warranted.

OBJECTIVE

To investigate the linear and potential nonlinear associations between sex-specific risk factors and the risk of new-onset AF in women.

DESIGN, SETTING, AND PARTICIPANTS

This population-based cohort study obtained data from the 2006 to 2010 UK Biobank study, a cohort of more than 500 000 participants aged 40 to 69 years. Participants were women without AF and history of hysterectomy and/or bilateral oophorectomy at baseline. Median follow-up period for AF onset was 11.6 years, and follow-up ended on October 3, 2020.

EXPOSURES

Self-reported, sex-specific risk factors, including age at menarche, history of irregular menstrual cycle, menopause status, age at menopause, years after menopause, age at first live birth, years after last birth, history of spontaneous miscarriages, history of stillbirths, number of live births, and total reproductive years.

MAIN OUTCOMES AND MEASURES

The primary outcome was new-onset AF, which was defined by the use of International Statistical Classification of Diseases and Related Health Problems, Tenth Revision code I48.

RESULTS

A total of 235 191 women (mean [SD] age, 55.7 [8.1] years) were included in the present study. During follow-up, 4629 (2.0%) women experienced new-onset AF. In multivariable-adjusted models, history of irregular menstrual cycle was associated with higher AF risk (hazard ratio [HR], 1.34; 95% CI, 1.01-1.79). Both early menarche (age 7-11 years; HR, 1.10 [95% CI, 1.00-1.21]) and late menarche (age 13-18 years; HR, 1.08 [95% CI, 1.00-1.17]) were associated with AF incidence. Early menopause (age 35-44 years; HR, 1.24 [95% CI, 1.10-1.39]) and delayed menopause (age ≥60 years; HR, 1.34 [95% CI, 1.10-1.78]) were associated with higher risk of AF. Compared with women with 1 to 2 live births, those with 0 live births (HR, 1.13; 95% CI, 1.04-1.24) or 7 or more live births (HR, 1.67; 95% CI, 1.03-2.70) both had significantly higher AF risk.

CONCLUSIONS AND RELEVANCE

Results of this study suggest that irregular menstrual cycles, nulliparity, and multiparity were associated with higher risk of new-onset AF among women. The results highlight the importance of taking into account the reproductive history of women in devising screening strategies for AF prevention.

Motherhood Health Penalty: Impact of Fertility on Physical and Mental Health of Chinese Women of Childbearing Age

Background

The negative consequences of childbearing on mothers are called the motherhood penalty, and it manifests in the aspects of women's physical and mental health. In May 2021, China relaxed its birth policy that allowed a married couple to have three children. It gives women the opportunity to have more children, but also may increase more risks to mothers' physical and mental health.

Objectives

The objectives of this study were to clarify the relationships between the fertility and the physical/mental health of women of childbearing age and empirically confirm the existence of the motherhood health penalty in China.

Materials and Methods

Using a nationally representative dataset from the China Labor-force Dynamics Survey 2018, we examined the effects of fertility on the physical and mental health of Chinese women of childbearing age. Physical health was self-rated, and mental health was assessed according to the Center for Epidemiological Studies Depression scale. The instrumental variable approach and the models of inverse probability of treatment weighting of propensity scores and regression adjustment were employed to overcome the endogeneity between fertility and health of women.

Results

The empirical results showed that the total number of births had significant adverse impacts on the physical and mental health of women of childbearing age, which empirically demonstrated the existence of the motherhood health penalty in China. The results of heterogeneity analysis indicated that the physical and mental health of the rural women was more easily affected by childbearing compared with that of the urban samples. In a mechanism analysis, the pathways of income and the multiple roles played by mothers were found to mediate the impacts of the total number of births on the physical and mental health of women. The robustness checks showed that the results of this study were robust.

Conclusions

The findings of this study extend the motherhood penalty to the health domain, and they have important implications for improving healthcare policy for women of childbearing age in China and other countries and regions and promoting gender equality in the healthcare field.

Reproductive history and blood cell DNA methylation later in life: the Young Finns Study

Background

Women with a history of complications of pregnancy, including hypertensive disorders, gestational diabetes or an infant fetal growth restriction or preterm birth, are at higher risk for cardiovascular disease later in life. We aimed to examine differences in maternal DNA methylation following pregnancy complications.

Methods

Data on women participating in the Young Finns study (n = 836) were linked to the national birth registry. DNA methylation in whole blood was assessed using the Infinium Methylation EPIC BeadChip. Epigenome-wide analysis was conducted on differential CpG methylation at 850 K sites. Reproductive history was also modeled as a predictor of four epigenetic age indices.

Results

Fourteen significant differentially methylated sites were found associated with both history of pre-eclampsia and overall hypertensive disorders of pregnancy. No associations were found between reproductive history and any epigenetic age acceleration measure.

Conclusions

Differences in epigenetic methylation profiles could represent pre-existing risk factors, or changes that occurred as a result of experiencing these complications.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-021-01215-1.

Higher Parity Is Associated With Lower Mortality in a European Population of Women With High Fertility: Results From Ireland

Research has often found a U- or J-shaped association between parity and mortality. Many researchers have suggested repeated pregnancy, childbirth, and lactation taxes the body beyond a certain parity level. Available research has concentrated on populations with controlled fertility or historic populations. Ireland presents an opportunity to explore these associations in a modern sample with high fertility. We use data from the Irish Longitudinal Study on Ageing (TILDA) to test whether parity is associated with mortality in women aged 50 years or over (n = 4177). We use Cox proportional hazards models to model survival and adjust for demographics and early life circumstances. We test whether a number of health characteristics mediate these effects. Models were also stratified by birth cohort to test possible cohort effects. Higher parity was associated with lower risk of mortality, even after adjustment for early life and socioeconomic circumstances. This effect was not mediated by current health characteristics. The effects were largely driven by those born between 1931 and 1950. Increasing parity is associated with decreasing mortality risk in this sample. The effects of parity could not be explained through any of the observed health characteristics. These findings are in contrast to much of the literature on this question in similar populations. Lack of fertility control in Ireland may have "selected" healthier women into high parity. Social explanations for these associations should be further explored.

Faster life history strategy manifests itself by lower age at menarche, higher sexual desire, and earlier reproduction in people with worse health

Factors which indicate lower life expectancy also induce switching to a faster life strategy, that is, a higher investment in current reproduction at the expense of future reproduction and body maintenance. We tested a hypothesis according to which impairment of individual health serves as a signal for switching to a faster life strategy using online-gathered data from 32,911 subjects. Worse health was associated with lower age at menarche and earlier initiation of sexual life in women and higher sexual desire and earlier reproduction in both sexes. Individuals with worse health also exhibited lower sexual activity, lower number of sexual partners, and lower total number of children. These results suggest that impaired health shifts individuals towards a faster life strategy but also has a negative (physiological) effect on behaviours related to sexual life. Signs of a faster life strategy were also found in Rh-negative men in good health, indicating that even just genetic predisposition to worse health could serve as a signal for switching to a faster life strategy. We suggest that improved public health in developed countries and the resulting shift to a slower life strategy could be the ultimate cause of the phenomenon of demographic transition.

Effects of Fertility Behaviors on Depression Among the Elderly: Empirical Evidence From China

Background: Increased population aging is associated with increased incidence of depression among the elderly. Existing studies have shown that ill-advised fertility behaviors during their youth also affect the health of the elderly. However, insufficient attention has been paid to depression among elderly in China. This paper focuses on how fertility behaviors affect senile depression among parents by examining the heterogeneity of such effects and tests the applicability of existing theoretical findings in a Chinese sample.

Methods: The effects of fertility behaviors on depression among the elderly were investigated using the China Health and Retirement Longitudinal Study (CHARLS), a nationally representative dataset. The effects of early-age fertility behaviors on the degree of depression among the elderly were investigated using ordinary least squares and ordered probit models that adjusted for demographic and socioeconomic factors.

Results: (1) The age of first childbirth, childbearing period, and number of births were significantly and positively correlated with the degree of depression among the elderly (particularly rural persons aged 50–70 and older womens). (2) Elderly persons with sons had no better mental health status than those without sons, thus indicating the inapplicability of the traditional concept of “more sons are equal to more happiness” to the actual mental health situation of the elderly in China today.

Conclusion: Overall, multiple, late, and boy-oriented childbearing and overly long childbearing periods had negative effects on mental health among Chinese elderly persons. This study tested the applicability of existing theoretical inferences and empirical conclusions in China, thereby further expanding the current literature regarding the effects of fertility behaviors on depression among the elderly.

Environmental adversity is associated with lower investment in collective actions

Environmental adversity is associated with a wide range of biological outcomes and behaviors that seem to fulfill a need to favor immediate over long-term benefits. Adversity is also associated with decreased investment in cooperation, which is defined as a long-term strategy. Beyond establishing the correlation between adversity and cooperation, the channel through which this relationship arises remains unclear. We propose that this relationship is mediated by a present bias at the psychological level, which is embodied in the reproduction-maintenance trade-off at the biological level. We report two pre-registered studies applying structural equation models to test this relationship on large-scale datasets (the European Values Study and the World Values Survey). The present study replicates existing research linking adverse environments (both in childhood and in adulthood) with decreased investment in adult cooperation and finds that this association is indeed mediated by variations in individuals’ reproduction-maintenance trade-off.

Frailty: A cost incurred by reproduction?

Evolutionary theories of senescence, such as the ‘disposable soma’ theory, propose that natural selection trades late survival for early fecundity. ‘Frailty’, a multidimensional measure of health status, may help to better define the long-term consequences of reproduction. We examined the relationship between parity and later life frailty (as measured by the Frailty Index) in a sample of 3,534 adults aged 65 years and older who participated in the English Longitudinal Study of Ageing. We found that the most parous adults were the most frail and that the parity-frailty relationship was similar for both sexes. Whilst this study provided some evidence for a ‘parity-frailty trade-off’, there was little support for our hypothesis that the physiological costs of childbearing influence later life frailty. Rather, behavioural and social factors associated with rearing many children may have contributed to the development of frailty in both sexes.

Influence of Offspring on Self-Rated Health among Older Adults: Evidence from the Korean Longitudinal Study of Aging (2006-2012)

BACKGROUND

We investigated whether offspring protect or jeopardize in parents.

METHODS

We used data from the Korean Longitudinal Study of Aging and performed a longitudinal analysis of 10,236 individuals at baseline (2006) to estimate the association between offspring-related factors and self-rated health among individuals ≥45 years of age.

RESULTS

The estimate for self-rated health was 0.612 times lower (95% confidence interval [CI], 0.503-0.746; P<0.0001) for those with zero offspring. The estimate for self-rated health was 0.736 (95% CI, 0.635-0.853; P<0.0001) for those with five offspring or more. The estimate for self-rated health was 0.707 (95% CI, 0.528-0.947; P=0.020) for males with zero offspring. The estimate for self-rated health was 0.563 (95% CI, 0.422-0.751; P<0.001) for females with no offspring and for females with five or more offspring. The estimate for self-rated health was 0.686 times lower (95% CI, 0.573-0.822; P<0.0001) for those with five or more offspring compared to females with two offspring.

CONCLUSION

Those with more offspring (≥5) and those with no offspring tended to have an increased probability of low self-rated health. Overall, our results suggest that offspring have a significant positive effect on self-rated health, which was evident graphically as an inverted U-shape.

Reproductive history and physical functioning in midlife: The Bogalusa Heart Study

OBJECTIVE

To examine the relationship between reproductive history, pregnancy complications, and later physical function.

STUDY DESIGN

The Bogalusa Heart Study is a long-running study of cardiovascular health in a semirural community. 761 women were interviewed about their pregnancy history and complications, and underwent tests of physical function. Logistic models for dichotomous outcomes and linear models for continuous outcomes were used, adjusted for covariates.

MAIN OUTCOME MEASURES

Overall scores on the Short Physical Performance Battery (SPPB), which combines scores for balance, gait speed, and chair stands. Additional tests were a 6-min walk, knee extension strength, grip strength, and a pegboard challenge.

RESULTS

Nulliparity was associated with lower scores on the walking and balance portions of the SPPB, less distance covered in the 6-min walk, less knee and grip strength, and higher pegboard time, especially among pre-menopausal women. A history of gestational diabetes was associated with more problems on the walk portion of the SPPB (aOR 2.44, 1.06-5.65), higher chair stand time, and lower knee strength. Young age at first birth (<16 or 18 years) was associated with a shorter chair stand time and a better pegboard score.

CONCLUSIONS

Nulliparity was associated with worse physical functioning, while high parity and early pregnancy were not, suggesting that fertility is associated with better health later in life. Pregnancy complications were associated with worse physical functioning, even after controlling for body mass index. Future studies should attempt to establish the pathways by which reproductive health relates to overall physical functioning.

Reproductive Investment and Health Costs in Roma Women

In this paper, we examine whether variation in reproductive investment affects the health of Roma women using a dataset collected through original anthropological fieldwork among Roma women in Serbia. Data were collected in 2014–2016 in several Roma semi-urban settlements in central Serbia. The sample consisted of 468 Roma women, averaging 44 years of age. We collected demographic data (age, school levels, socioeconomic status), risk behaviors (smoking and alcohol consumption), marital status, and reproductive history variables (the timing of reproduction, the intensity of reproduction, reproductive effort and investment after birth), in addition to self-reported health, height, and weight. Data analyses showed that somatic, short-term costs of reproduction were revealed in this population, while evolutionary, long-term costs were unobservable—contrariwise, Roma women in poor health contributed more to the gene pool of the next generation than their healthy counterparts. Our findings appear to be consistent with simple trade-off models that suggest inverse relationships between reproductive effort and health. Thus, personal sacrifice—poor health as an outcome—seems crucial for greater reproductive success.

Human reproduction and health: an evolutionary perspective

According to life history theory, increased investment in reproductive function (physiology and behaviour) at different times throughout the life course affects the risk of many diseases and, ultimately, longevity. Although genetic factors contribute to interindividual and interpopulation variation in reproductive traits, the dominant source of variability is phenotypic plasticity during development and adult life. Reproductive traits in both sexes evolved sensitivity to ecological conditions, as reflected in contemporary associations of hormone concentrations with geographical setting, nutritional status, and physical activity level. Lifetime exposure to increased concentrations of sex hormones is associated with the risk of some cancers, hence decreasing fertility patterns contribute to secular increases in their incidence. Conversely, increased investment in reproductive function might compromise somatic investment in health, such that faster sexual maturation and higher parity increases risk of diabetes and cardiovascular disease. An evolutionary perspective on reproductive biology could improve the efficacy of public health efforts to reduce the risk of hormone-sensitive cancers and other non-communicable diseases.

Age Trajectories of Physical Health Among Older Adults of Mexican Descent: Implications of Immigrant Status, Age at Immigration, and Gender

OBJECTIVE

This study examines consequences of immigrant status, age at immigration, and gender on age trajectories of activities of daily living (ADL) limitations and chronic conditions among older adults of Mexican descent.

METHOD

This research draws on 7 waves of the Hispanic Established Populations for the Epidemiologic Study of the Elderly and employs growth curve models.

RESULTS

All men had similar age trajectories of ADL limitations, regardless of immigrant status and age at immigration. All women experienced steeper increases in ADL limitations, although U.S.-born women and those who immigrated by age 19 had lower initial levels. Men who immigrated between ages 20 and 49 had steeper increases in chronic conditions, despite lower initial levels. U.S.-born women and those women who immigrated by age 50 had more chronic conditions at age 65.

DISCUSSION

This study highlights the multidimensional nature of physical health by demonstrating that immigrant status-gender disparities can vary by the health outcome examined.

Functional limitation trajectories and their determinants among women in the Philippines

BACKGROUND

Limited evidence exists regarding how functional limitation patterns of women in developing countries unfold through midlife and into old age, a critical period during which the tendency to develop severe problems is fomented.

OBJECTIVE

Functional limitation prevalence and patterns through midlife into early old age, and their determinants, are examined among women in the Philippines.

METHODS

Data from the Cebu Longitudinal Health and Nutrition Study are monitored from 1994 to 2015. Patterns are categorized using group-based trajectory modeling. Predictors of group membership are modeled.

RESULTS

About half responding to all survey waves report functional limitation at least once over the study period. Movements in and out of functional limitation states are common. Between age 30 and 70, trajectories are categorized into four groups: 1) robust, 2) late onset, 3) early onset, and 4) recovery. Being married, living in a nuclear household, higher successful birth ratio, and higher education associate with favorable trajectories. More births, higher age at first birth, wealth, and urbanicity associate with less favorable trajectories.

CONCLUSION

Many possible routes into and out of functional limitation exist. The manifold patterns can be grouped into common trajectories. A number of earlier life characteristics associate with these trajectories.

CONTRIBUTION

This is the first analysis to ascertain common functional limitation trajectories and earlier life predictors among women as they age in a high fertility developing country setting. Recognizing these is an important step toward understanding global health given aging of the population and the likelihood of functional problems developing in women as they move into old age.

Family size and old-age wellbeing: effects of the fertility transition in Mexico

The present study aims to determine how family size affects psycho-social, economic and health wellbeing in old age differently across two cohorts with declining fertility. The data are from the 2012 Mexican Health and Ageing Study (MHAS) including respondents aged 50+ (N = 13,102). Poisson (standard and zero-inflated) and logistic regressions are used to model determinants of wellbeing in old age: psycho-social (depressive symptoms), economic (consumer durables and insurance) and health (chronic conditions). In the younger cohort, having fewer children is associated with fewer depressive symptoms and chronic conditions, and better economic well-being. For the older cohort, having fewer children is associated with lower economic wellbeing and higher odds of being uninsured. Lower fertility benefited the younger cohort (born after 1937), whereas the older cohort (born in 1937 or earlier) benefited from lower fertility only in chronic conditions. Further research is needed to continue exploring the old-age effects of the fertility transition.

Female fertility history and mid-late-life health: Findings from China

China's middle-aged and older women suffer from poorer health than men. Using national baseline data from the China Health and Retirement Longitudinal Study (CHARLS), a survey conducted from 2011 to 2012, this article applies logistic models to investigate the association between female fertility history (parity, early childbearing, late childbearing) and middle-aged and late-life health. We find that parity is related to the mid-late-life health of women. Women with four children or more are more likely to suffer from activities of daily living (ADL) impairment and poorer self-rated health than those with one to three children. Early childbearing is associated with ADL impairment; however, the correlation is mediated by socioeconomic status. Early childbearing is related to self-rated health in later life by an indirect-only mediation effect via educational attainment and personal income.

Childbearing History and Self-Reported Well-Being in Later Life

The authors examined how numbers of live births and pregnancy losses affected the self-rated health and depressive symptoms of women aged 50 years and older, contrasting African Americans and Whites. The authors used data from Atherosclerosis Risk in Communities, a large, prospective study with substantial minority representation. They tested hypotheses that childbearing-history variables would influence self-rated well-being among older women and that perceived social support would mediate the associations. The authors also tested whether these associations would be stronger among older African American versus White women. The results suggest that the impact of child-bearing history is greater among older African American than White women. Pregnancy loss worsened depressive symptoms and self-rated health among African American women; the effect was reduced by social-support variables. High parity was associated with worse self-rated health among African American women, mediated by social support. Having no live births was not associated with diminished well-being among older women of any race.

The impact of education and health heterogeneity on Generational Support Ratios: a cross-national comparison between Mexico and Korea

Policy makers are concerned about the socio-economic consequences of population ageing. Policies often rely on estimations of support ratios based solely on the population age structure. We estimate Generational Support Ratios (GSRs) considering health heterogeneity of the population age 60+ and education heterogeneity of their offspring. We explore the effect of a public policy that changes the education of a targeted sub-group of women when they are young on their health once they become older, taking into account changes in demographic processes (i.e.marriage, fertility, offspring's education). We used the model presented by Kyeet al.for the Korean context and examine the Mexican context. Our paper has three objectives. First, by applying this framework to the Mexican context we aim to find that improvements in women's education may mitigate the negative consequences of population ageing directly and indirectly through subsequent demographic behaviours that altogether affect GSRs. Second, by making a cross-national comparison between Korea and Mexico, we aim to quantify how policies of educational expansion have different impacts in contexts in which the population age 60+ have universal access to health care compared to contexts in which access to health care is selective. Third, by comparing cross-nationally we aim to show how differences in family processes across countries alter the pathways through which improvements in education affect GSRs.

Do fertility control policies affect health in old age? Evidence from China's one-child experiment

How do fertility control policies contribute to the welfare of women, and their husbands, particularly as they get older? We consider whether the reduction in fertility resulting from population control policies has had any effect on the health of elderly parents in China. In particular, we examine the influence of this fertility decline, experienced due to China's one-child policy, on several measures of the health of parents in middle and old age. Overall, our results suggest that having fewer children has a positive effect on self-reported parental health but generally no effect on other measures of health. The results also suggest that upstream financial transfers have a positive effect on several measures of parental health.

Early life effects across the life course: the impact of individually defined exogenous measures of disease exposure on mortality by sex in 19th- and 20th-century Southern Sweden

Using micro-level longitudinal data from Southern Sweden for 1813 to 1968, this work evaluates the effect of exposure to disease in early life on mortality over the entire life course and separately by sex. The local rates of post-early neonatal mortality are considered indicators of early life disease exposure, and these rates are calculated specifically for each person based on birth date. The loss in median remaining life among exposed individuals who survived to age 1 is 1.1 years for females and 2.1 years for males. Exposed individuals show a cross-over from lower to higher relative mortality as they age. This change occurs in adulthood for males and in old age for females. During adulthood, exposed males present higher rates of death than exposed females. These results are new to the literature and shed light on the importance of adopting a full life course approach and capturing sex differences when evaluating the long-term impacts of early life exposures.

Pregnancy as a risk factor for ambulatory limitation in later life

OBJECTIVES

We investigated the relationship between the number of times a woman has been pregnant and walking difficulty in later life.

METHODS

With data from the Hispanic Established Populations for Epidemiologic Studies of the Elderly, a representative population-based cohort of Mexican Americans aged 65 years and older residing in 5 Southwestern states, we measured walking difficulty using 2 items from the performance-oriented mobility assessments: the timed walk and seated chair rise.

RESULTS

We observed significantly higher rates of ambulatory limitation among women with 6 or more pregnancies than among women with 4 or fewer pregnancies: 44.9% and 27.0%, respectively, were unable to perform or performed poorly in the seated chair rise and timed walk. Ordinal logistic regression models show that gravidity predicts level of performance in both mobility tasks and that higher gravidity is associated with worse performance, even after adjustment for both age and chronic disease.

CONCLUSIONS

Gravidity is a risk factor for ambulatory limitation in old age. A life course approach to reproduction in public health research and practice is warranted.

Fertility history and quality of life in older women and men

In this paper we examine associations between the fertility histories of older British women and men and their quality of life using data on a sample of 6,374 men and women born between 1923 and 1949 drawn from the British Household Panel Survey (BHPS). Quality of life in 2001 was measured using scores from the four subscales of the CASP-19 questionnaire: control, autonomy, pleasure and self-realisation. Fertility histories were derived using information on the births of children collected in all waves of the BHPS. The aspects of fertility history investigated were number of children born and parents' ages at birth of first and last child. Age, education, marital status, tenure status, smoking, co-residence with one or more children, perceived social support and health limitations were included as covariates. The results suggested that early entry to parenthood and to some extent high parity were related to poorer quality of life. These associations were mostly mediated by socio-economic, social support and health factors. Compared to women with two children, nulliparous women expressed a higher level of autonomy, and both nulliparous women and those with four or more children a higher level of self-realisation. Low parity was related to a lower level of pleasure, especially among men, but this relationship appeared weaker and among women was not significant when background factors were controlled.

Marital history, health and mortality among older men and women in England and Wales

BACKGROUND

Health benefits of marriage have long been recognised and extensively studied but previous research has yielded inconsistent results for older people, particularly older women. At older ages accumulated benefits or disadvantages of past marital experience, as well as current marital status, may be relevant, but fewer studies have considered effects of marital history. Possible effects of parity, and the extent to which these may contribute to marital status differentials in health, have also been rarely considered.

METHODS

We use data from the Office for National Statistics Longitudinal Study, a large record linkage study of 1% of the population of England & Wales, to analyse associations between marital history 1971-1991 and subsequent self-reported limiting long-term illness and mortality in a cohort of some 75,000 men and women aged 60-79 in 1991. We investigate whether prior marital status and time in current marital status influenced risks of mortality or long term illness using Poisson regression to analyse mortality differentials 1991-2001 and logistic regression to analyse differences in proportions reporting limiting long-term illness in 1991 and 2001. Co-variates included indicators of socio-economic status at two or three points of the adult life course and, for women, number of children borne (parity).

RESULTS

Relative to men in long-term first marriages, never-married men, widowers with varying durations of widowerhood, men divorced for between 10 and twenty years, and men in long-term remarriages had raised mortality 1991-2001. Men in long-term remarriages and those divorced or widowed since 1971 had higher odds of long-term illness in 1991; in 2001 the long-term remarried were the only group with significantly raised odds of long-term illness. Among women, the long-term remarried also had higher odds of reporting long-term illness in 1991 and in 2001 and those remarried and previously divorced had raised odds of long-term illness and raised mortality 1991-2001; this latter effect was not significant in models including parity. All widows had raised mortality 1991-2001 but associations between widowhood of varying durations and long-term illness in 1991 or 2001 were not significant once socio-economic status was controlled. Some groups of divorced women had higher mortality risks 1991-2001 and raised odds of long-term illness in 1991. Results for never-married women showed a divergence between associations with mortality and with long-term illness. In models controlling for socio-economic status, mortality risk was raised but the association with 1991 long-term illness was not significant and in 2001 never-married women had lower odds of reporting long-term illness than women in long-term first marriages. Formally taking account of selective survival in the 20 years prior to entry to the study population had minor effects on results.

CONCLUSIONS

Results were consistent with previous studies in showing that the relationship between marital experience and later life health and mortality is considerably modified by socio-economic factors, and additionally showed that taking women's parity into account further moderated associations. Considering marital history rather than simply current marital status provided some insights into differentials between, for example, remarried people according to prior marital status and time remarried, but these groups were relatively small and there were some disadvantages of the approach in terms of loss of statistical power. Consideration of past histories is likely to be more important for later born cohorts whose partnership experiences have been less stable and more heterogeneous.

Reproductive history, socioeconomic status and disability in the women aged 65 years or older in Turkey

Pregnancy and childbirth are an important physiological and emotional phenomenon in their lives for most women and studies have shown that this process may have a significant impact on their health at later ages. The objective of the study is to examine the relationship between functional disabilities in women over the age of 65 and their reproductive history and socioeconomic status. This is a cross-sectional study. The study group consisted of 543 women aged 65 or over. A general questionnaire and the Brief Disability Questionnaire (BDQ) were used to collect data with face-to-face interview in home visits. Of the women 79.2% have disability. First childbirth was experienced at the average age of 19.6+/-3.3 and the average age at which the women experienced their last delivery was 32.5+/-6.3. Parity was 4.1+/-1.7. Advanced age, being widowed and illiterate, less income, being outside of the middle class and having more than four children are important determinants for later life disability. The study highlights the importance of focusing not just on the short-term effects of childbearing and socioeconomic factors, but also of taking into account the possibility of long-term effects on disability in older women.

The Long-Term Consequences of Childbearing: Physical and Psychological Well-Being of Mothers in Later Life

Growing evidence points to relationships between patterns of childbearing and health outcomes for mothers; yet a need remains to clarify these relationships over the long-term and to understand the underlying mechanisms. Using data from the National Longitudinal Survey of Mature Women (N=1,608), I find that the long-term consequences of childbearing vary by health outcome. Early childbearing is associated with higher risk of ADL limitations at ages 65-83, though effects appear stronger among white than black mothers until SES is controlled. Early childbearing is also associated with greater levels of depressive symptomatology, though this association is mediated by SES and health. Late childbearing is associated with more depressive symptoms net of early life and current SES, child proximity and support, and physical health. Finally, I find no significant effects of high parity. These findings emphasize the need to better understand the mechanisms linking childbearing histories to later physical and psychological well-being.

Early motherhood and mental health in midlife: a study of British and American cohorts

OBJECTIVES

Examine the relationship between early age at first birth and mental health among women in their fifties.

METHODS

Analysis of data on women from a British 1946 birth cohort study and the U.S. Health and Retirement Study birth cohort of 1931-1941.

RESULTS

In both samples a first birth before 21 years, compared to a later first birth, is associated with poorer mental health. The association between early first birth and poorer mental health persists in the British study even after controlling for early socioeconomic status, midlife socioeconomic status and midlife health. In the U.S. sample, the association becomes non-significant after controlling for educational attainment.

CONCLUSIONS

Early age at first birth is associated with poorer mental health among women in their fifties in both studies, though the pattern of associations differs.

Early childbearing, marital status, and women's health and mortality after age 50

This article examines the relationship between a woman's childbearing history and her later health and mortality, with primary focus on whether the association between them is due to early and later socioeconomic status. Data are drawn from the Health and Retirement Study birth cohort of 1931-1941. Results indicate that, conditional on reaching midlife and controlling for early and later socioeconomic status, a first birth before age 20 is associated with a higher hazard of dying. In addition, having an early birth is associated with a higher prevalence of reported heart disease, lung disease, and cancer in 1994. Being unmarried at the time of the first birth is associated with earlier mortality, but this association disappears when midlife socioeconomic status is controlled. The number of children ever born does not significantly affect mortality but is associated with prevalence of diabetes.

Inequalities in health: a comparative study between ethnic Norwegians and Pakistanis in Oslo, Norway

BACKGROUND

The objective of the study was to observe the inequality in health from the perspective of socio-economic factors in relation to ethnic Pakistanis and ethnic Norwegians in Oslo, Norway.

METHOD

Data was collected by using an open and structured questionnaire, as a part of the Oslo Health Study 2000-2001. Accordingly 13581 ethnic Norwegians (45% of the eligible) participated as against 339 ethnic Pakistanis (38% of the eligible).

RESULTS

The ethnic Pakistanis reported a higher prevalence of poor self-rated health 54.7% as opposed to 22.1% (p < 0.001) in ethnic Norwegians, 14% vs. 2.6% (p < 0.001) in diabetes, and 22.0% vs. 9.9% (p < 0.001) in psychological distress. The socio-economic conditions were inversely related to self-rated health, diabetes and distress for the ethnic Norwegians. However, this was surprisingly not the case for the ethnic Pakistanis. Odd ratios did not interfere with the occurrence of diabetes, even after adjusting all the markers of socio-economic status in the multivariate model, while self-reported health and distress showed moderate reduction in the risk estimation.

CONCLUSION

There is a large diversity of self-rated health, prevalence of diabetes and distress among the ethnic Pakistanis and Norwegians. Socio-economic status may partly explain the observed inequalities in health. Uncontrolled variables like genetics, lifestyle factors and psychosocial factors related to migration such as social support, community participation, discrimination, and integration may have contributed to the observed phenomenon. This may underline the importance of a multidisciplinary approach in future studies.

Fertility history and health in later life: a record linkage study in England and Wales

Women born at different periods within the 20th century in England and Wales have followed varying fertility pathways with large changes in, for example, proportions having no children or only one child. Among the consequences of these changes may be effects on women's health later in life. Links between fertility histories and later health and mortality have been investigated in several studies, but in many of these socio-economic characteristics have not been allowed for, even though there are socio-economic differences in both fertility and mortality patterns and results are conflicting. Here we analyse associations between the fertility histories of women born 1911-1940 in England and Wales and their mortality and health status after age 50. We used data from the Office for National Statistics Longitudinal Study; a record linkage study of approximately 1% of the population initially based on those enumerated in the 1971 Census of England and Wales. We used survival analysis to investigate the effects of parity, short birth intervals, and timing of fertility on mortality from age 50 to the end of 2000, controlling for a range of relevant socio-demographic characteristics. For survivors to 1991, we additionally used logistic regression to model probability of having a limiting long-term illness in 1991. We found that nulliparous women and women with five or more children had significantly higher mortality than other women, and that in the oldest groups women with just one child also had raised mortality. Women who had been teenage mothers had higher mortality and higher odds of poor health than other parous women. Mothers with short birth intervals, including mothers of twins, also had elevated risks in some cohorts. Late childbearing (after age 39) was associated with lower mortality. Personal demographic history is an important factor to consider in analyses of health and mortality variations in later life. More research is needed to further elucidate causal pathways.

Long-term effects of childbearing on mortality: evidence from pre-industrial Sweden

This paper presents an analysis of the impact of childbearing history on later-life mortality for ever-married men and women using historical micro-level data of high quality for southern Sweden. The analysis uses a Cox proportional hazards model, estimating the effects on old-age mortality of number of births and timing of first and last births. By studying the effects of previous childbearing on mortality by sex and social status, we also gain important insights into the mechanisms relating childbearing to mortality in old age. The results show that number of children ever born had a statistically significant negative impact on longevity after age 50 for females but not for males. Analysis by social group shows that only landless women experienced higher mortality from having more children, which seems to indicate that the main explanations are to be found in social or economic conditions specific to females, rather than in the strictly biological or physiological effects of childbearing.

Ethnicity, acculturation, and self reported health. A population based study among immigrants from Poland, Turkey, and Iran in Sweden

STUDY OBJECTIVE

To analyse the association between ethnicity and poor self reported health and explore the importance of any mediators such as acculturation and discrimination.

DESIGN

A simple random sample of immigrants from Poland (n = 840), Turkey (n = 840), and Iran (n = 480) and of Swedish born persons (n = 2250) was used in a cross sectional study in 1996. The risk of poor self reported health was estimated by applying logistic models and stepwise inclusion of the explanatory variables. The response rate was about 68% for the immigrants and 80% for the Swedes. Explanatory variables were: age, ethnicity, educational status, marital status, poor economic resources, knowledge of Swedish, and discrimination.

MAIN RESULTS

Among men from Iran and Turkey there was a threefold increased risk of poor self reported health than Swedes (reference) while the risk was five times higher for women. When socioeconomic status was included in the logistic model the risk decreased slightly. In an explanatory model, Iranian and Turkish women and men had a higher risk of poor health than Polish women and men (reference). The high risks of Turkish born men and women and Iranian born men for poor self reported health decreased to non-significance after the inclusion of SES and low knowledge of Swedish. The high risks of Iranian born women for poor self reported health decreased to non-significance after the inclusion of low SES, low knowledge of Swedish, and discrimination.

CONCLUSIONS

The strong association between ethnicity and poor self reported health seems to be mediated by socioeconomic status, poor acculturation, and discrimination.

Social capital, the miniaturisation of community and self-reported global and psychological health

Social capital is often operationalised as social participation in the activities of the formal and informal networks of civil society and/or as generalised trust. Social participation and trust are two aspects of social capital that mutually affect each other, according to the literature. In recent years there has been an increased attention to the fact that generalised trust decreases for every new birth cohort that reaches adulthood in the USA, while social participation may take new forms such as ideologically much narrower single-issue movements that do not enhance trust. The phenomenon has been called "the miniaturisation of community". The effects of similar patterns in Sweden on self-reported health and self-reported psychological health are analysed. The odds ratios of bad self-reported global health are highest in the low-social capital category (low-social participation/low trust), but the miniaturisation of community and low-social participation/high-trust categories also have significantly higher odds ratios than the high-social capital category (high-social participation/high trust). The odds ratios of bad self-reported psychological health are significantly higher in both the low-social capital category and the miniaturisation of community category compared to the high-social capital category, while the low-social participation/high-trust category does not differ from the high-social capital reference group.

Premature death among teenage mothers

OBJECTIVE

Some data suggest an association between teenage childbearing and premature death. Whether this possible increase in risk is associated with social circumstances before or after childbirth is not known. We studied premature death in relation to age at first birth, social background and social situation after first birth.

DESIGN

Population-based cohort study.

SETTING

Women born in Sweden registered in the 1985 Swedish Population Census.

POPULATION

Swedish women born 1950-1964 who had their first infant before the age of 30 years (N= 460,434).

METHODS

Information on the women's social background and social situation after first birth was obtained from Population Censuses. The women were followed up with regard to cause of death from December 1, 1990 to December 31, 1995. Mortality rate ratios and 95% confidence intervals (CI) were calculated.

MAIN OUTCOME MEASURES

Mortality rates by cause of death.

RESULTS

Independent of socio-economic background, teenage mothers faced an increased risk of premature death later in life compared with older mothers (rate ratio 1.6, 95% CI 1.4-1.9). The increased risk was most evident for deaths from cervical cancer, lung cancer, ischaemic heart disease, suicide, inflicted violence and alcohol-related diseases. Some, but not all, of these increases in risk were associated with the poorer social position of teenagers mothers.

CONCLUSIONS

Teenage mothers, independent of socio-economic background, face an increased risk of premature death. Strategies to reduce teenage childbearing are likely to contribute to improved maternal and infant health.

Individual self-reported health, social participation and neighbourhood: a multilevel analysis in Malmö, Sweden

BACKGROUND

The influence of neighbourhood and individual factors on self-reported health was investigated.

METHODS

The public health survey in Malmö 1994 is a cross-sectional study. A total of 3,602 individuals aged 20-80 living in 75 neighbourhoods answered a postal questionnaire. The participation rate was 71%. A multilevel logistic regression model, with individuals at the first level and neighbourhoods at the second, was performed. We analysed the effect (intra-area correlation, cross-level modification and odds ratios) of neighbourhood on self-reported health after adjustment for individual factors.

RESULTS

The neighbourhoods accounted for 2.8% of the crude total variance in self-reported health status. This effect was significantly reduced when individual factors such as country of origin, education and social participation were included in the model. In fact, no significant variance in self-reported health remained after the introduction of the individual factors in the model.

CONCLUSIONS

In Malmö, the neighbourhood variance in self-reported health is mainly affected by individual factors, especially country of origin, socioeconomic status measured as level of education and individual social participation.

An exploration of health concerns & health-promotion behaviors in pregnant women over age 35

PURPOSE

To explore the specific health concerns and health-promotion behaviors of childbearing women 35 years of age or older.

STUDY DESIGN AND METHODS

Semistructured interviews with women ( = 50) ages > or =35 in their third trimester of pregnancy. Interviews lasted approximately 1 hour, were conducted by two nursing faculty, and were scheduled to accommodate participant needs. Process recording was used to document participant responses. Verbatim statements were recorded, and subjects were redirected to clarify responses when necessary. Content analysis and coding were completed by an independent researcher, based upon techniques derived from Miles and Huberman (1994). Data reduction was accomplished by the identification of categories of responses that described the participants' meaning.

RESULTS

Study participants reported concerns reflecting both fetal well-being and maternal health-related issues. The majority of childbearing women (86%) reported engaging in multiple health-promotion behaviors focusing on daily nutritional intake, lifestyle activities, and rest patterns. Participants reported conscientious decisions to eliminate substances recognized as harmful, and to alter exercise, employment, or daily responsibilities to accommodate physical changes during pregnancy. Participants were "proactive healthcare seekers," accessing information from a variety of sources and seeking services to meet their individualized needs.

CLINICAL IMPLICATIONS

The multitude and frequency of health-promotion behaviors adopted by those > or =35 years of age during pregnancy is indicative of this group's ability to independently initiate change, and exceeds the percentages previously reported. The nurse can be influential in supporting lifestyle modifications adopted during the childbearing period as permanent health-promotion behaviors.

The Innsbruck Women's Health Study 1999: health status and behaviour

OBJECTIVES

The aim of this study is to report descriptive results of a recent survey on women's health and to analyse associations between perceived health status and health behaviour.

METHODS

A cross-sectional survey on 609 women aged 20 to 95 years was performed in Innsbruck (Austria) in 1999.

RESULTS

Self-reported poor health status was 6% in the 20-39 age group, 10% in the 40-59 age group and 20% in the 60 and older age group. Age and physical activity were significant predictors for health status. Women who performed physical activities on a regular basis had a more than 70% reduced risk of poor health status. Concerning the prevalence of self-reported morbidity, urogenital disorders (35%), allergies (32%), and headache (42%) were most frequent in younger women whereas skeletal disorders such as rheumatic diseases (41%), osteoporosis (39%), and invertebral disc damage (39%) in older women. Important health behaviour-related problems to be found were 40% smoking among women under 40, and 42% overweight or obesity among women over 60. Stress affected 37% of women under 60 years of age.

CONCLUSIONS

Physical activity, smoking, overweight and stress revealed to be key-indicators for improving women's health.

Ethnic differences in self reported health in Malmö in southern Sweden

STUDY OBJECTIVE

The aim of this study was to investigate ethnic differences in self reported health in the city of Malmö, Sweden, and whether these differences could be explained by psychosocial and economic conditions.

DESIGN/SETTING/PARTICIPANTS

The public health survey in Malmö 1994 was a cross sectional study. A total of 5600 people aged 20-80 years completed a postal questionnaire. The participation rate was 71%. The population was categorised according to country of origin: born in Sweden, other Western countries, Yugoslavia, Poland, Arabic speaking countries and all other countries. The multivariate analysis was performed using a logistic regression model in order to investigate the importance of possible confounders on the differences by country of origin in self reported health. Finally, variables measuring psychosocial and economic conditions were introduced into the model.

MAIN RESULTS

The odds ratios of having poor self reported health were significantly higher among men born in other Western countries, Yugoslavia, Arabic speaking countries and in the category all other countries, as well as among women born in Yugoslavia, Poland and all other countries, compared with men and women born in Sweden. The multivariate analysis including age and education did not change these results. A huge reduction of the odds ratios was observed for men and women born in Yugoslavia, Arabic speaking countries and all other countries, and for women born in Poland after the introduction of the social network, social support and economic factors into the multivariate model.

CONCLUSIONS

There were significant ethnic group differences in self reported health. These differences were greatly reduced by psychosocial and economic factors, which suggest that these factors may be important determinants of self rated health in certain minority groups.

Adult life experiences and health in early old age in Great Britain

In Britain and other developed countries older people comprise a large majority of all those reporting long term illness or disability. However, most studies of socio-demographic variations in health have focussed on those in younger age groups. Moreover approaches to the study of health variations are often fragmented. In this study we have adopted a life course approach to analyse differentials in health in early old age. The data comes from the Retirement and Retirement Plans Survey and follow-up, a two-wave study of persons aged 55-69 in 1988/9. As well as information on current circumstances, the data set includes occupational, marital, and fertility history information. At baseline a nationally representative sample of the population of Great Britain were interviewed at home by trained interviewers (n = 3543). The sample was followed up and in 1994, 2247 survivors were re-interviewed, a response rate of 70% (of survivors). The data were weighted to adjust for non-response bias. Two outcome measures were used: self rated health and presence or absence of disability assessed from a scale derived from detailed questions on thirteen domains of disability. The severity score used was that developed for the 1985/6 ONS Surveys of Disability. The findings indicate that health and disability status at baseline and at follow up were associated with socioeconomic and geographic variables, such as proportion of adult life spent unemployed and residence outside the Southeast of England; demographic factors, such as early age at marriage and high parity; and experience of adverse events, such as the death of a child and being dismissed from work. The results show that socio-economic, demographic, and geographical and life events' factors are all associated with health status in early old age and that integrated, rather than bifurcated, approaches to the study of health differentials are needed.