Genetic regulation of growth from birth to 18 years of age: The Swedish young male twins study

Growth is a complex process, and only little is known on the genetic regulation of it. We analyzed the effect of genetic and environmental factors on growth in a longitudinal Swedish cohort of 231 monozygotic and 144 dizygotic twin pairs born 1973–1979 with length or height measured annually from birth to age 18. The data were analyzed by two different multivariate variance component models for twin data using the Mx statistical package. At birth and 1 year of age, a substantial part of the variation in length was because of common environment (50 and 57%, respectively) and the effect of genetic factors was minor. After 2 years of age, 91–97% of the variation of height could be explained by genetic differences whereas the rest was because of environmental variation not shared by twins. The genetic correlation between heights at ages 2 and 18 was 0.73 (95% confidence intervals 0.68–0.77) showing that 53% of the genes affecting height at these ages are the same or closely linked; with increasing age the correlation with genetic effects at age 18 become subsequently stronger. Especially in mid‐childhood, growth was largely regulated by the same genetic factors. During puberty new genetic factors started to affect height, but also genetic variation affecting height at previous ages remained. These results suggest that genetic regulation of growth is rather uniform, which is encouraging for further efforts to identify genes affecting growth. Am. J. Hum. Biol., 2008. © 2008 Wiley‐Liss, Inc.     

Genetic and environmental factors affecting self-esteem from age 14 to 17: a longitudinal study of Finnish twins

BACKGROUND: We analysed genetic and environmental influences on self-esteem and its stability in adolescence. METHOD: Finnish twins born in 1983-1987 were assessed by questionnaire at ages 14 (n = 4132 twin individuals) and 17 years (n = 3841 twin individuals). Self-esteem was measured using the Rosenberg global self-esteem scale and analyzed using quantitative genetic methods for twin data in the Mx statistical package. RESULTS: The heritability of self-esteem was 0.62 [95% confidence interval (CI) 0.56-0.68] in 14-year-old boys and 0.40 (95% CI 0.26-0.54) in 14-year-old girls, while the corresponding estimates at age 17 were 0.48 (95% CI 0.39-0.56) and 0.29 (95% CI 0.11-0.45). Rosenberg self-esteem scores at ages 14 and 17 were modestly correlated (r = 0.44 in boys, r = 0.46 in girls). In boys, the correlation was mainly (82%) due to genetic factors, with residual co-variation due to unique environment. In girls, genetic (31%) and common environmental (61%) factors largely explained the correlation. CONCLUSIONS: In adolescence, self-esteem seems to be differently regulated in boys versus girls. A key challenge for future research is to identify environmental influences contributing to self-esteem during adolescence and determine how these factors interact with genetic influences.     

Attachment and development: a prospective, longitudinal study from birth to adulthood

There is much to digest in a 30 year longitudinal study of the developing person (Sroufe, Egeland, Carlson, & Collins, 2005a). The following paper summarizes some key points regarding the place of infant attachment in the developmental course. It is argued that understanding the role of attachment entails grasping the organizational nature of the attachment construct and embracing a non-linear transactional model. Using such concepts, attachment history was shown in the Minnesota study to be clearly related to the growth of self-reliance, the capacity for emotional regulation, and the emergence and course of social competence, among other things. Moreover, specific patterns of attachment had implications for both normal development and pathology. Even more important than such linkages, however, study of the place of early attachment in later adaptation reveals much about developmental processes underlying both continuity and change. Findings are over-viewed concerning the complex links between attachment and ultimate outcomes and the preservation of early patterns even during times of change. In all, these findings have implications both for future research and for clinical application.     

Determinants of growth in body length from birth to 6 years of age: A longitudinal study of Lublin children

The effect of determinants of growth in body length from birth to 6 years of age were studied in a longitudinal sample of 59 male and 70 female infants from Lublin, Poland. Structural equation modeling (SEM) was used to study the effects of gender of the child, occupation of the parents, the educational level of the parents, per capita income, the stature of the parents, and the weight of the mother on body length at birth and at 1, 2, 3, and 6 years of age. Significant sex differences in length were observed at birth and during the first 2 years of postnatal life, but not in the period between 3 and 6 years of age. Socioeconomic status (SES), expressed as a latent variable in the SEM, was not related to body length at birth but was significantly related to body length during infancy and, to a lesser extent, to body length during childhood. Paternal stature was not related to body length at birth and during infancy, but was significantly related to body length from 3 years onwards. Maternal stature was significantly related to body length at birth and at 1 year of age, but not thereafter, while maternal weight was significantly related to body length at birth only. © 1996 Wiley-Liss, Inc.     

Influenza virus infections from 0 to 2 years of age: A birth cohort study

Background/purposeInfluenza vaccine has been recommended in Finland since 2007 for all children of 6–35 months of age and in 2009 for those ≥6 months against pandemic influenza. We investigated the incidence of influenza and vaccine effectiveness in a birth cohort of children in 2008–2011.MethodsWe followed 923 children from birth to 2 years of age for respiratory tract infections. A nasal swab sample for PCR for influenza A and B viruses was taken at the onset of acute respiratory infections. Samples were collected either at the study clinic or at home by parents. Vaccination data was retrieved from the health registries.ResultsVaccination coverage of children aged 6–23 months was 22–47% against seasonal influenza and 80% against the A(H1N1)pdm09 virus in the pandemic season 2009–2010. During 3 influenza seasons, 1607 nasal swab samples were collected. Influenza was confirmed in 56 (6.1%) of 923 children (16 A(H1N1), 14 A(H3N2), and 26 B viruses). The incidence of influenza was 5.1% in 2008–2009, 2.7% in 2009–2010, and 5.0% in 2010–2011. Effectiveness of the adjuvanted vaccine against the pandemic influenza A(H1N1)pdm09 was 97% (95% confidence interval, 76–100%). Three children with influenza were hospitalized.ConclusionThe yearly incidence of seasonal influenza was 5% in this cohort of very young children with variable influenza vaccine coverage. Adjuvanted vaccine against the pandemic influenza was highly effective. Both seasonal and pandemic influenza cases were mostly non-severe.     

Lifestyle counseling during pregnancy and offspring weight development until four years of age: follow-up study of a controlled trial

Background

Fetal conditions are known to be partly responsible for the child??s risk for obesity. Our pilot study aimed to determine the effect of gestational lifestyle counseling on the offspring weight gain until 4?years of age and to estimate power for future studies.

Design and methods

First-time pregnant mothers participated in a controlled trial conducted in maternity health clinics during 2004 ?C 2006. The intervention included individual counseling on physical activity and diet, and an option to attend supervised group exercise sessions. The participant mothers (N?=?109) received a follow-up questionnaire concerning 13 repeated growth measurements of their offspring. Response rate to the follow-up questionnaire was 66.1% (N?=?72/109).

Results

The increase of BMI z-score between 24?C48?months was not significantly slower among the intervention group offspring (95% CI ?0.025 to 0.009, p?=?0.34) compared to control group. Z-scores for weight-for-length/height did not differ between groups when the period 0?C48?months was analyzed (95% CI ?0.010 to 0.014, p?=?0.75).

Conclusions

In this pilot study gestational lifestyle counseling did not significantly slow the weight gain of the offspring. Gestational intervention studies with at least 300 mothers per group are needed to confirm the possible effect on offspring??s risk for obesity.

Trial registration

Current Controlled Trials ISRCTN21512277.     

Outcome from a prospective, longitudinal study of prenatal cocaine use: preschool development at 3 years of age

OBJECTIVE: To determine the effects of prenatal cocaine exposure on child development. METHODS: This prospective, longitudinal study recruited 154 pregnant cocaine users who were matched on race, parity, socioeconomic status, and perinatal risk to 154 noncocaine users. Drug use status was determined by maternal history and urine screening. At 3 years of age, the child subjects were assessed by an evaluator blinded to maternal drug use history. During a home visit at age 3, caregiver, family, and home assessments were administered. RESULTS: Structural equation modeling showed a direct effect of the amount of prenatal cocaine exposure on the adjusted birth head circumference which in turn directly affected preschool development. CONCLUSIONS: We could not demonstrate a direct effect of prenatal cocaine exposure on preschool development, a result that is consistent with that of earlier work and now extending findings to age 3. However, cocaine continued to exert an indirect effect on development through its direct effect on the head circumference at birth.     

The comparative growth of Efe pygmies and African farmers from birth to age 5 years

Recent studies of African pygmies have concluded that the pattern of pygmy growth is similar to that of other Africans up to the time of puberty and that the short stature of adult pygmies is due primarily, if not solely, to the absence of accelerated adolescent growth. These conclusions are thought to be consistent with biochemical studies showing pygmies to have low levels of insulin-like growth factor 1 (IGF-1). All previous pygmy-growth studies have been of subjects of estimated, not known age. This paper reports the results of a mixed longitudinal growth study of Efe pygmy children of known age from birth to age 5 years. The mean adult stature of Efe pygmies is the shortest of any human population known, including other pygmy populations of central Africa. At birth, Efe were significantly smaller than neighbouring Lese Sudanic-speaking farmers and other rural Africans. During the first 5 years of life, Efe not only remained shorter than Lese controls at all ages, but the difference in stature between them increased. Unlike the Lese, Efe children showed a trend of increasingly negative z scores compared with the American reference population, from -2.71 (SD = 0.93) at 6 months to -4.16 (SD = 0.46) at age 5 years. These results indicate that suppression of pygmy growth does not occur solely at puberty, but from birth onward. Furthermore, they suggest that conclusions concerning the lack of an adolescent pygmy growth spurt have been premature and must await studies of older pygmy sub-adults of known age.     

The association of unplanned pregnancy with perinatal depression: a longitudinal cohort study

Archives of Women's Mental Health - Perinatal depression is common, affecting approximately 7–13% of women. Studies have shown an association between unplanned pregnancy and perinatal...     

Immune response to Campylobacter jejuni and Campylobacter coli in a cohort of children from birth to 2 years of age.

A cohort of 111 children from Bangui, Central African Republic, was surveyed for enteric Campylobacter infections from birth to the age of 2 years; stools were examined biweekly in these children until 6 months of age and at least four times per year thereafter until 2 years of age and after each diarrheal episode. Blood samples were obtained at birth and at 3, 6, 9, 12, 18, and 24 months of age. Antibodies against glycine-extracted membrane antigens, purified flagella, and cholera toxin (CT) were assayed by an enzyme-linked immunosorbent assay. The results showed that titers of antibody against the three tested antigens increased in children between 6 and 12 months of age and that nearly all children were immunized by the age of 2 years. A significant fall in anti-flagellum (P less than 0.001) and anti-glycine extract antibodies (P less than 0.001) occurred between birth and age 3 months, and children who had Campylobacter infections during the first 6 months of life had significantly (P less than 0.02) less anti-flagellum antibodies at birth than did those who did not have Campylobacter infections during that time. Three-month-interval stratification showed that CT antibody titers at birth were significantly lower in children who developed Campylobacter infection than in controls (P = 0.05). Comparison of the immune response to a single Campylobacter episode showed that 46.6% of children with asymptomatic carriage did not respond to CT while only 5% of children with diarrhea-producing infection did not respond to CT (P less than 0.01), compared with 30% (P = 0.065) and 56% (P less than 0.01), respectively, of the age-matched controls. Antibodies to flagella seem to protect against enteric colonization by Campylobacter jejuni and Campylobacter coli.     

Prolonged exclusive breastfeeding is associated with increased atopic dermatitis: a prospective follow-up study of unselected healthy newborns from birth to age 20 years

BACKGROUND: Exclusive breastfeeding for the first 6 months is recommended by the World Health Organization and considered allergy preventive. However, it is not known whether prolonging exclusive breastfeeding for over 6 months provides further benefit in allergy prevention. OBJECTIVE: The aim of this prospective 20-year follow-up study was to find out whether the allergy protective effect can be enhanced by prolonging strictly exclusive breastfeeding for > or =9 months of age. A total of 200 unselected healthy newborns were enrolled in the study. Their mothers were encouraged to maintain exclusive breastfeeding for as long as possible. The number of infants on strictly exclusive breastfeeding was 167 at 2, 116 at 6, 36 at 9 and 7 at 12 months of age. Of the 200 infants, 42% had a family history of allergy. The children were re-assessed at ages 5 (n=163), 11 (n=150) and 20 years (n=164) with clinical examination, skin prick testing, and parental and personal structured interviews. RESULTS: Exclusive breastfeeding prolonged for > or =9 months was associated with atopic dermatitis (P=0.002) and symptoms of food hypersensitivity (P=0.02) at age 5 years, and with symptoms of food hypersensitivity at age 11 years (P=0.01), in children with a family history of allergy. CONCLUSION: Prolonging strictly exclusive breastfeeding for > or =9 months was not helpful in atopy prevention, instead, it was associated with increased atopic dermatitis and food hypersensitivity symptoms in childhood.     

Sensitization to inhalant allergens between 4 and 8 years of age is a dynamic process: results from the BAMSE birth cohort

Background There is limited knowledge of the development of IgE-antibody levels over time in childhood, with respect to persistency and co-sensitization to specific inhalant allergens.
Methods Data from 2033 children participating in the BAMSE birth cohort was used. Background factors and clinical parameters were obtained and IgE antibody (ab) levels to eight common airborne allergens were measured (0.35 kU_A/L) when the children were 4 and 8 years of age.
Results Between 4 and 8 years the proportion of children sensitized to any of the inhalant allergens tested increased from 15% to 25%. At 4 years IgE-ab to birch and cat dominated, whereas at the age of 8, there was a considerable increase in the proportion of sensitization to timothy and dog. Except for mites and moulds, IgE-ab levels to all aeroallergens increased significantly between 4 and 8 years among those already sensitized at 4. Transient sensitization to inhalant allergen was uncommon. Furthermore, sensitization to birch pollen at 4 years increased the risk for becoming sensitized to timothy, cat and dog later in life. Such an association was not observed among those sensitized primarily to animal dander.
Conclusions There is a prominent process of sensitization at pre-school age to inhalant allergens, and in Northern Europe sensitization to birch pollen early in life seems to be important for this process. Such a process has a probable impact on the development of allergic disease in the growing child.     

Genetic and environmental influences on growth from late childhood to adulthood: a longitudinal study of two Finnish twin cohorts

Objectives: Human growth is a complex process that remains insufficiently understood. We aimed to analyze genetic and environmental influences on growth from late childhood to early adulthood. Methods: Two cohorts of monozygotic and dizygotic (same sex and opposite sex) Finnish twin pairs were studied longitudinally using self‐reported height at 11–12, 14, and 17 years and adult age (FinnTwin12) and at 16, 17, and 18years and adult age (FinnTwin16). Univariate and multivariate variance component models for twin data were used. Results: From childhood to adulthood, genetic differences explained 72–81% of the variation of height in boys and 65–86% in girls. Environmental factors common to co‐twins explained 5–23% of the variation of height, with the residual variation explained by environmental factors unique to each twin individual. Common environmental factors affecting height were highly correlated between the analyzed ages (0.72–0.99 and 0.91–1.00 for boys and girls, respectively). Genetic (0.58–0.99 and 0.70–0.99, respectively) and unique environmental factors (0.32–0.78 and 0.54–0.82, respectively) affecting height at different ages were more weakly, but still substantially, correlated. Conclusions: The genetic contribution to height is strong during adolescence. The high genetic correlations detected across the ages encourage further efforts to identify genes affecting growth. Common and unique environmental factors affecting height during adolescence are also important, and further studies are necessary to identify their nature and test whether they interact with genetic factors. Am. J. Hum. Biol., 2011. © 2011Wiley‐Liss, Inc.     

Early childhood factors associated with the development of post-traumatic stress disorder: results from a longitudinal birth cohort

BACKGROUND: Childhood factors have been associated with increased risk of developing post-traumatic stress disorder (PTSD). Previous studies assessed only a limited number of childhood factors retrospectively. We examined the association between childhood neurodevelopmental, temperamental, behavioral and family environmental characteristics assessed before age 11 years and the development of PTSD up to age 32 years in a birth cohort. METHOD: Members of a 1972-73 New Zealand birth cohort (n=1037) who were assessed at ages 26 and 32 years for PTSD as defined by DSM-IV. RESULTS: We identified two sets of childhood risk factors. The first set of risk factors was associated both with increased risk of trauma exposure and with PTSD assessed at age 26. These included childhood externalizing characteristics and family environmental stressors, specifically maternal distress and loss of a parent. The second set of risk factors affected risk for PTSD only and included low IQ and chronic environmental adversity. The effect of cumulative childhood factors on risk of PTSD at age 26 was substantial; over 58% of cohort members in the highest risk quartile for three developmental factors had PTSD as compared to only 25% of those not at high risk on any factors. Low IQ at age 5, antisocial behavior, and poverty before age 11 continued to predict PTSD related to traumatic events that occurred between the ages of 26 and 32. CONCLUSIONS: Developmental capacities and conditions of early childhood may increase both risk of trauma exposure and the risk that individuals will respond adversely to traumatic exposures. Rather than being solely a response to trauma, PTSD may have developmental origins.