Growing up healthy, wealthy , and wise

Growing up healthy, wealthy, and wise

By Janet B. Hardy, MD, CM, and Therese L. Miller, DrPH

All of us want to see children become self-sufficient, self-respecting adults; the question is, what makes it happen? A landmark study has identified one of the variables—the age of a child's mother when she first gives birth. The data should give every pediatrician pause, and food for thought.

May your baby grow up to be healthy, wealthy, and wise" was a common birthday wish for babies born half a century ago. Most new mothers today would echo the sentiment. The wish often comes true, at least in some measure. But the likelihood of success is smaller for some children than others, particularly those born into poor, socially disadvantaged families, regardless of ethnic background, and, recent research indicates, those born to teenage mothers.

Should not pediatricians and others responsible for the health and development of children and adolescents have the same long-term wish—healthy, successful lives—for their patients? Do we consider the potential for health and self-sufficiency in adulthood of the child or teen we examine today? What can we do to promote a successful outcome 15 to 30 years in the future?

Few of us think in these terms, although pediatricians have long been strong proponents of the "whole child" approach to managing patients, which views health and development within the context of the family. One reason may be that little information has been available to guide us through the minefield of complex interactions between the biological and environmental factors that determine child and adolescent development. Until recently, developmental research has been fragmented along specific disciplinary lines among pediatricians and related medical specialists, sociologists, psychologists, educators, and economists.

The last half century has seen accelerating change in pediatric practice, change that sometimes seems schizophrenic. On the one hand, an increasingly biotechnological approach has evolved to further the understanding of pathophysiological processes and their diagnosis and treatment by subspecialists (with results that sometimes seem magical). On the other hand, an equally strong and healthy emphasis has developed on preventing a broad spectrum of problems ranging from infectious disease, perinatal problems, and neuropsychiatric and cognitive dysfunction to teenage parenthood and cigarette, drug, and alcohol abuse.

In both these important streams of pediatric practice a life-course development approach can provide the foundation on which to plan how to maximize the developmental potential of each child.

The life-course development model

The life-course development model provides a structural framework for considering factors that may affect the development of children from conception through adolescence and beyond. It is based on the theory that children enter the world at birth with a personal history that began at conception and a dual genetic and cultural heritage received from each parent. The genetic heritage is immutable, but environmental factors may modify its expression. A good example is the relationship between nutrition and growth in height: While height is genetically determined, the less adequate the nutritional intake, the shorter the stature will be. The cultural heritage may be changed if, for example, the child is not raised by the biological parents, who usually determine the characteristics of the cultural milieu in which the child is socialized.

During pregnancy, fetal health and development are influenced by genetic endowment, maternal health and pregnancy factors. In addition, environmental conditions such as toxic substances and family stress are mediated through their effect on the mother. During and after birth, environmental influences affect individual development directly.

Table 1 outlines the life-course model from conception through adolescence. The lefthand column lists major categories of biological and health influences along with the time periods within which they may exert their effects. The righthand column lists characteristics of the family and community environment that also affect development, changing with the age of the child. Some children, because of exposure to both biological and family and environmental risk factors, are at double jeopardy for failure.

The developmental end result, at any given point along the trajectory, reflects the individual child's positive or negative adaptation to complex interactions between his or her innate characteristics and the health and environmental influences to which the child has been exposed. If the adaptation is in a positive direction, the influencing factor is considered to be protective, that is, to facilitate normal development. If the adaptation is negative, the influencing factor is a risk for poor developmental outcome.

According to a 30-year longitudinal study by Werner and Smith of children born in 1957 on the Island of Kauai, where most children were socially disadvantaged, a balance between protective and risk factors was required to facilitate normal developmental progress to adulthood.¹ The authors concluded that, in general, family and environmental characteristics were stronger predictors of adult outcome than adverse perinatal events, and that a warm and affectionate relationship with a care-taking adult had a strong protective effect in an adverse environment. Indeed, a stable, warm, affectionate relationship that generates trust with parents and other caregivers who also serve as role models is essential for optimal development.

An abundance of information links antecedent characteristics and events in children's lives with later developmental adversity. The social science literature abounds in papers describing the adverse effects of poverty, social disadvantage, and family dissolution.^2­5 The pediatric literature also provides much information about antecedent biological risk factors and their adverse outcomes. Two striking examples are the potentially devastating fetal consequences of maternal infections such as rubella and human immunodeficiency virus and the well-recognized relationship between perinatal risk factors such as low birthweight and prematurity and neuropsychological problems such as cerebral palsy, mental retardation, and developmental delay (which may, in fact, result from antecedent risks that pass unrecognized).

Little of the interdisciplinary cross-fertilization needed to account for the "double jeopardy" of biological and environmental influences on life-course development has taken place until recently. At least three longitudinal studies extending from birth to adulthood are now available that meet this need: Werner and Smith's 1992 study,¹ The British Child Development Study (Ferri, 1993; Manlove, 1997)^6,7 of a large, representative sample of children born in 1958, and The Johns Hopkins University Pathways to Adulthood study.⁸ Data from the Pathways to Adulthood study illustrate the value of an intergenerational life course approach in providing insight into complex biosocial problems, specifically those resulting in and stemming from teenage parenthood.

The Pathways to Adulthood study

The Pathways to Adulthood Study has been described in detail elsewhere.^8,9 It had its genesis in the National Collaborative Perinatal Project (CPP) in which Johns Hopkins participated.^10­13 In the CPP, over 50,000 pregnant women in the first generation (G-1) were enrolled at their first prenatal visit between 1959 and 1965. Detailed observations, including collection of maternal sera and cord blood, were made throughout pregnancy.

Surviving children in the second generation (G-2) were followed with their mothers until the children were 7 or 8 years of age. Repeated observations were made of the children's health; physical, neurologic, cognitive, social, and behavioral development; and the family and environmental circumstances in which they lived.

In 1992 to 1993, when the G-2 children were 27 to 33 years of age, a random sample of those born at Johns Hopkins between 1960 and 1965 and followed to 8 years of age (n = 2,694) was selected for extensive interviewing to ascertain their adult outcome status and bridge the information gap for the period between 8 years and the time of the interview. Interviews were completed with 1,758 (65.3%) of the G-2 sample.

We use results from analyses that controlled for many background factors (race, gender, mother's education, marital status, parity, and poverty status) to illustrate how one factor (among others) present at birth—maternal age—has a lasting impact on adult self-sufficiency.

Mother's age and child's adult outcome

As shown in Table 2, a G-2 child's age when he or she first becomes a parent is a strong predictor of his or her own success as an adult. For example, only 23% of G-2 women and 14% of G-2 men in our study who became parents before 20 years of age graduated from high school; in contrast, 47% of women and 60% of men who postponed parenthood until at least 25 years of age graduated from high school. There is not anything particularly new about these results. Numerous studies have examined the long-term impact of teenage childbearing on the parent and child.¹⁴

Few have looked at the intergenerational effects of early parenthood, however. We first examined whether a G-1 mother's age at the birth of her first child has a long-term effect on her child's success as an adult, similar to the effect of the child's own age at parenthood. We found that a G-1 mother's age when she first gave birth was significantly associated with her G-2 children's self-sufficient function 30 years later, regardless of their birth order. Multiple logistic regression analysis indicated, for example, that daughters of the mothers who first gave birth at 25 years or older were 10 times more likely to graduate from high school, eight times more likely to be independent of public assistance, and twice as likely to have good mental health as daughters born to teenage mothers. Similar, though less robust, relationships were found between the mothers' age at first birth and their sons' adult outcomes.

Mother's age and family characteristics

While the mother's age at the birth of her first child strongly predicted adult outcomes for all her children, not just the first, the specific developmental mechanisms have not been identified. Our clinical experience suggests that the developmental characteristics of most inner- city teenage parents and the unstable circumstances in which they live are the antithesis of those required for good parenting. The combination of immaturity and lack of good role models, knowledge, and resources required for quality parenting fosters continuation of both teenage parenthood and the poverty cycle. Our research results confirm our clinical impressions.

Older G-1 mothers were 10 times more likely to have graduated from high school than teenage G-1 mothers. The older mothers also were more likely to have stable family relationships. They were four times more likely to be married than teenage G-1 mothers, and the child's father was more likely to be present in the household during childhood. They made fewer residential moves during their children's early years and adolescence than teenage G-1 mothers. Finally, older G-1 mothers were only 20% as likely to be receiving welfare as teenage G-1 mothers.

Mother's age and child characteristics

Maternal age at first giving birth also appears to affect a child's development throughout the life-course. We found, for example, that G-2 children born to the oldest mothers (25 years of age or older) were more than twice as likely to have a WISC IQ score of 90 or above at 7 years of age than children born to teenage mothers, and they were only 20% as likely to repeat a grade in school. In adolescence, significantly fewer children of older mothers smoked cigarettes, used marijuana and alcohol regularly, were arrested, dropped out of school, or reported that their friends were teenage parents. They were four times more likely to delay sexual activity to 16 years of age or older than children born to teenage mothers.

Intergenerational patterns of childbearing

We also examined whether G-2 children repeat their mothers' childbearing patterns. That is, do children of teenage mothers become teenage parents themselves, and do children of older mothers also postpone parenthood? We found significant intergenerational trends. While the majority of children born to teenage mothers did not become teenage parents, 38% of their daughters and 18% of their sons did. Among children born to women who had delayed their first birth to 25 years of age or older, the pattern was even stronger: 55% of daughters and 72% of sons also delayed parenthood to at least 26 years of age and few became teenage parents.

Thus, intergenerational data over a 27- to 33-year period show that patterns of age at first parenthood from generation to generation are a reality and that the mother's age at first birth is an independent determinant of the adult self-sufficiency of both her daughters and her sons, regardless of their birth order. Furthermore, these intergenerational patterns are in turn related to:

• the characteristics of the family environment in which the child grew up, with the family characteristics of older mothers being more favorable for the optimal development of children than those of teenage mothers.

• the developmental characteristics of the child, with children of older mothers showing on average more favorable developmental and behavioral characteristics during childhood and adolescence than children of teenage mothers.

An eye on the future

While we have summarized results from complex research looking at the long-term effects of maternal age, we do not intend this article to be specifically about maternal age or teenage childbearing. Rather, we hope to use maternal age to draw attention to the life-course development model. Pediatricians focus on child development but perhaps in too limited a manner. In addition to treating the child of today, they should have their eyes on the future, recognizing the long-term impact on adult outcome of the child's personal, family, and environmental characteristics as the child's developmental status changes over the life-course. Perhaps more than any other professionals, pediatricians are in the best position to intervene early in the life-course of most children to keep their development on a normal track.

What can pediatricians do? Those responsible for the health, education, and well-being of children have important roles to play in children's life chances. The direct route is through clinical care, both acute and preventive. Preventive care, in addition to immunization against infectious disease, includes health and parenting education and anticipatory guidance-providing knowledge pertaining to normal development, nutrition, and how to protect children from a range of hazards to their normal development.

With today's lack of good role models for appropriate parenting that encourages the development of parent-child attachment and trust, parenting must be taught. Our research suggests that pediatricians should emphasize a family- centered approach to their patients. Given the time constraints of office visits, this calls for careful planning. Useful tools include simple, age-appropriate printed handouts; parenting discussion groups provided by the practice (for which a modest fee may be charged) or referral to community resources for parent education; books; and Internet resources. Remember that material handed directly to the patient will command more attention that material left on a table for parents to pick up.

A special direct responsibility of pediatricians to adolescent patients and their parents is to make sure that preteens and teens have the information they need to protect themselves from the risks of premature sexual activity and parenthood, smoking, drinking, and antisocial behavior. Information provided by a trusted physician lends credence that is hard to beat.

We must not overlook the importance of our indirect role as advocates for children and their parents, making sure, through the political process, that all children have the opportunity to become self-sufficient adults.

REFERENCES

1. Werner EE, Smith RS: Overcoming the Odds: High Risk Children from Birth to Adulthood. Ithaca, NY, Cornell University Press, 1992

2. Elder GH: Children of the Great Depression. Chicago, The University of Chicago Press, 1977

3. Edelman MW: Families in Peril: An Agenda for Social Change. Cambridge, MA, Harvard University Press, 1987

4. Wilson WJ: The Truly Disadvantaged. Chicago, The University of Chicago Press, 1987

5. Cherlin AJ: Marriage, Divorce, Remarriage. Cambridge, MA, Harvard University Press, 1992

6. Ferri E (ed): Life at 33: The Fifth Follow-up of the National Child Development Study. London, England, National Children's Bureau, 1993

7. Manlove J: (1997). Early motherhood in an intergenerational perspective: The experiences of a British cohort. Journal of Marriage and the Family 1997;59:262

8. Hardy JB, Shapiro S, Mellits ED, et al: Self-sufficiency at ages 27 to 33 years: Factors present between birth and 18 years that predict educational attainment among children born to inner-city families. Pediatrics 1997;99:80

9. Hardy JB, Astone NM, Brooks-Gunn J, et al: Like mother, like child: Intergenerational patterns of age at first birth and associations with childhood and adolescent characteristics and adult outcomes in the second generation. Developmental Psychology 1998;34:1220

10. Niswander KR, Gordon M: The Women and their Pregnancies: The Collaborative Perinatal Study of the National Institute of Neurologic Diseases and Stroke. Philadelphia, WB Saunders and Company, 1972

11. Hardy JB, Drage JS, Jackson E: The First Year of Life. Baltimore, MD, The Johns Hopkins Press, 1979

12. Lassman FM, Fisch RO, Vetter KD, et al (eds): Early Correlates of Speech, Language, and Hearing. Little, MA, PSG Company, 1980

13. Broman SH, Nichols PL, Kennedy WA: Preschool IQ: Early Developmental Correlates. Hillsdale, NJ, Lawrence Erlbaum Associates, 1975

14. Hofferth SL, Hayes CD: Risking the Future, Vol 1: Adolescent Sexuality, Pregnancy, and Childbearing. Washington, DC, National Academy Press, 1987

DR. HARDY is Professor Emeritus of Pediatrics at The Johns Hopkins School of Medicine, Baltimore.

DR. MILLER is Research Associate, Department of Population and Family Health Sciences, School of Public Health, The Johns Hopkins University.

Janet Hardy,Therese Miller. Growing up healthy, wealthy , and wise.

Contemporary Pediatrics

2000;2:63.