10.2.5. Developmental factors and age

 

 

 

10.2.5.1. Introduction

Adult physical and mental health is linked to childhood developmental risk factors. There is evidence for links between nutritional and psychological factors during childhood and adult health. Identification of early developmental factors offers possibilities for health promotion activities already during foetal life and early infancy.

 

Environmental influence on health during foetal life and infancy is significant (Seckl, 2008). Early life environmental events have persisting effects on tissue structure and function, a phenomenon called developmental programming. Although many developmental factors influence health, the long-term effects of foetal nutrition and early psychological attachment are linked with the strongest evidence from longitudinal studies (Seckl, 2008).

 

10.2.5.2. Data sources

 

Data on developmental determinants of health are not readily available in Europe. The European Community Health Indicator (ECHI) long list includes the indicator “Pregnant women smoking”, but data collection has not been implemented. The ECHI long list does not include indicators on foetal nutrition or early attachment.

Neither the WHO Health for All database nor the Eurostat statistics provide any information on developmental determinants of health. The present section is built on scientific papers published in the open literature and quoted in the relevant section.

 

The European Early Promotion Project (EEPP) was a research project for developing and evaluating early mother and child interaction to promote child health and prevent psychosocial problems (Puura et al, 2002). The research was conducted in Finland, Great Britain, Greece, Cyprus and the former Federal Republic of Yugoslavia, and it provides the only comparative European data on early mother-child interaction.

 

10.2.5.3. Data description and analysis

 

The Barker theory links foetal malnutrition with risk for physical diseases later in life. Empirical longitudinal cohort studies in Europe have evidenced the association between low birth weight or height and adult risk for high blood pressure, type 2 diabetes, and cardio-vascular death (Barker et al, 2005, Eriksson et al, 2006). Longitudinal cohort studies from Finland, the Netherlands and UK have linked low birth weight to mental disorders like schizophrenia (Wahlbeck et al, 2001) and depression (Gale and Martyn, 2004). Therefore, it is likely that impaired neurodevelopment during foetal life, due to malnutrition, increases susceptibility to mental disorders. Foetal malnutrition can be due to maternal malnutrition (being rare these days), placental dysfunction, gestational diabetes or even maternal smoking. Longitudinal data from birth cohorts in Europe indicate that maternal smoking during pregnancy is also associated with psychological symptoms later in life (Bastra et al, 2003, Indredavik et al, 2007).

Human brain development is vulnerable. Environmental factors, in other words divergent stimulus and the infant's emotional experiences from a relationship with caregiver(s) are involved in formation of the mind. Some of this development is experience-expectant, in other words, certain stimulus is needed for normal development at a certain time. Some development on the other hand is experience-dependent, less dependant of the time and quality of the stimulus (Black 1998). Even though brain continues maturation till late adolescence, the most important developmental period occurs during foetal life and childhood. Infant's early relationship with the caregiver(s) (usually mother) i.e, attachment relation, is associated with the child's social functioning and adaptation in childhood and later in life. Caregiver's capability to respond to the infant's needs gives the child emotional experience, which affects the development of the infant's brain and even formation of permanent models of behaviour. A multitude of research has linked early attachment problems with psychological symptoms and disorders in childhood (Madigan et al, 2007) and adolescence (Allen et al, 2007) and health problems of childhood (Mäntymaa et al, 2003).

 

However, early psychological development is also linked to physical health. Early developmental experiences affect social processes, associated physiological stress responses, and ultimately, health across the lifespan. A recent study (Gallo and Matthews 2006) evidenced that adolescents with higher avoidant attachment showed augmented blood pressure in conjunction with interactions with friends. Early attachment problems.

 

A complicating factor when assessing impact of chemical, biological and physical stressors on human health is that human vulnerability differs over age. An increasing number of scientific studies indicate the role of exposure during early life stages for later development of disease in adult life (window of vulnerability).

 

For example exposure to chemicals during early fetal development can cause brain injury at doses much lower than those affecting adult brain function. Recognition of these risks has led to evidence-based programmes of prevention, such as elimination of lead additives in petrol. Although these prevention campaigns are highly successful, most were initiated only after substantial delays. About 200 chemicals are known to cause clinical neurotoxic effects in adults. Despite an absence of systematic testing, many additional chemicals have been shown to be neurotoxic in laboratory models. The toxic effects of such chemicals in the developing human brain are not known and they are not regulated to protect children. Main obstacles to prevention of neuro-developmental deficits of chemical origin are the great gaps in testing chemicals for developmental neuro-toxicity and the high level of proof required for regulation”. Several adult cancer forms can be traced back to environmental exposures early in life. Unfortunately human data is scarce and we have to rely on animal data. A meta-analysis of animal data identified more than 50 chemicals causing cancer in adult life after peri-natal exposure. It is concluded that exposure to chemicals with a mutagenic mode of action during early life increases the susceptibility for developing tumours in later life. Endocrine disrupters represent a case when mutagenesis is not involved. Early life exposure to substances with estrogenic and androgenic activity have been indicated in certain, hormone dependent, cancer forms such as breast cancer in women and testicular- and prostate cancer in men. Testicular cancer is increasing in the European population. The cancer appears in young men aged 20-40, but the cancer process probably already starts during the foetal period or the early years of life which is indicated in an epidemiological study based on men from Sweden and Finland hinting at that environmental exposures early in life, probably via the mother, are likely to be major determinants of this disease.

 

Moreover, it should also be mentioned that the human body and its physiology change remarkably over the years also as a consequence of a long series of small biological alterations induced, in spite of the considerable recovery ability of the organism, by exposure to toxic and carcinogenic chemicals, biological pathogens and other stressors together with a reduction of the immunological function and the increase of genetic instability. Typical body changes of the elderly include an increase of fat mass and a reduction of lean mass and total water content of the body; such changes lead to a reduction of body distribution volume of water-soluble substances and to an increase of distribution volume of fat-soluble substances. Moreover, characteristic of old age, are:

 

-         increased blood levels of free fractions of many substances that would have been otherwise combined with plasma albumin, due to a reduction of plasma levels of albumin;

-         reduced motility and gastro-intestinal blood flow as well as gastric secretion and of mucosal surface, which may affect nutrient absorption and bioavailability of many substances;

-         deceased kidney haematic flow (about 1% each year after 50 years of age) and glomerular filtration speed (about 1 ml/minute each year after 40 years of age) due to a reduced number of nefrons; and

-         progressively reduced hepatic metabolism of xenobiotics, due to a reduction of competent enzymes;

 

The progressive exhaustion of functional reserves of organs and apparatuses and the associated farmaco-kinetic and farmaco-dynamic modifications, which induce an increased susceptibility to xenobiotics, are gradual processes depending on individual characteristics. Such consideration explains why a classification of old people only based on age (i.e. young old between 65 and 75 years: old old between 76 and 85 years of age; and oldest old with more than 86 years) is inadequate to evaluate the individual health status,

 

For a detailed analysis of diseases prevalent in different age groups see Chapter 9.

 

10.2.5.4. Control tools and policies

 

The developmental determinants of health have been addressed in health policies in a few Member States. Increasing knowledge about developmental determinants of health supports the notion of early intervention to promote health, i.e. health promoting interventions during pregnancy and early childhood. Interventions include health promotion in maternity care to ensure adequate foetal nutrition and reduce smoking, and interventions to support an early and nurturing interaction between caregivers and toddler. In Finland, a nationwide training programme for staff in child health clinics has been implemented to support early interaction between mother and child. A controlled evaluation of the programme indicated that staff capacity improved and that family satisfaction was higher in the intervention group, but effects on child development were more ambiguous.

 

10.2.5.5. Future developments

 

Current health promotion activities tend to oversee the fundamental developmental determinants of health, and there is a need to re-evaluate health promotion policies in light of research findings in the rapidly-developing field of developmental health.

 

10.2.5.6. References

Allen JP, Porter M, McFarland C (2007): The relation of attachment security to adolescents‘ paternal and peer relationships, depression, and externalizing behavior. Child Dev 2007;78:1222-39.

 

Barker DJP, Osmond C, Forsén TJ, Kajantie E, Eriksson JG (2005): Trajectories of growth among children who have coronary events as adults. N Engl J Med 2005;353:1802-909.

 

Bastra L, Hadders-Algra M, Neeleman J (2003): Effect of antenatal exposure to maternal smoking on behaviournal problems and academic achievement in childhood: prospective evidence from a Dutch birth cohort. Early human development 2003;75:21-33.

Black J (1998): How a child builds its brain: Some lessons from animal studies of neural plasticity. Prev Med 1998;27:168-71.

 

Eriksson JG, Osmond C, Kajantie E, Forsén TJ, Barker DJP (2006): Patterns of growth among children who later develop type 2 diabetes or its risk factors. Diabetologia 2006;49:2853 - 8

 

Gale CR, Martyn CN (2004): birth weight and later risk of depression in a national birth cohort. Br J Psychiatry 2004;184:28-33.

 

Gallo LC, Matthews KA (2006): Adolescents' attachment orientation influences ambulatory blood pressure responses to everyday social interactions. Psychosom Med 2006;68:253-61.

 

Indredavik M, Brubakk AM, Romundstad P, Vik T (2007): Prenatal smoking exposure and psychiatric symptoms in adolescence. Acta Paediatr 2007;96(3):377-82

Madigan S, Moran G, Schuengel C (2007): Unresolved maternal attachment representations, disrupted maternal behavior and disorganized attachment in infancy: Links to toddler behavior problems. J Child Psychol Psychiatry 2007;48:1042-50.

 

Mäntymaa M, Puura K, Luoma I, Salmelin R, Davis H, Tsiantis J, Ispanovic-Radojkovic V, Paradisiotou A, Tamminen T (2003): Infant-mother interaction as a predictor of child's chronic health problems. Child Care Health Dev 2003;29(3):181-91.

 

Puura K, Davis H, Papadopoulou K, Tsiantis J, Ispanovic-Radojkovic V, Rudic N, Tamminen T, Turunen M-M, Dragonas T, Paradisiotou A, Vizakou S, Roberts R, Cox A, Day C (2002) The European Early Promotion Project: A new primary health care service to promote children's mental health. Infant Mental Health Journal 2002;23(6):606-24. Available at http://www3.interscience.wiley.com/cgi-bin/fulltext/99520435/PDFSTART

 

Wahlbeck K, Forsen T, Osmond C, Barker D, Eriksson J (2001): Association of schizophrenia with low maternal body mass index, small size at birth and thinness during childhood. Arch Gen Psychiatry 2001;58(1):48-52.