Gestational Age and Autism Spectrum Disorder: Trends in Risk Over Time.

Autism Spectrum Disorder (ASD) is a serious neurodevelopmental disorder. Several previous studies have identified preterm birth as a risk factor for ASD but none has studied whether the association between gestational age and ASD has changed over time. This is a Danish population-based follow-up study including live-born singletons born in Denmark between 1980 and 2009, identified in the Danish Medical Birth Registry, a study population of 1,775,397 children. We used a Cox regression model combined with spline to study the risk for ASD by gestational age across three decades of birth cohorts. We included 19,020 children diagnosed with ASD. Across all birth year cohorts, we found that the risk of being diagnosed with ASD increased with lower gestational age (P-value: <0.01). Across all gestational weeks, we found a statistically significant higher risk estimates in birth cohort 1980 to 1989, compared to birth cohorts 1990 to 1999 and 2000 to 2009, respectively. No statistically significant difference in risk estimates was observed between birth cohort 1990 to 1999 and 2000 to 2009. The observed time trend in risk of ASD after preterm birth may reflect: (1) a change in the risk profile of persons with ASD due to the broadening of ASD diagnostic criteria over time; or (2) improved neonatal care for low GA infants, which has reduced risk of adverse outcomes like ASD in preterm children.

A Descriptive Study on the Neonatal Morbidity Profile of Autism Spectrum Disorders, Including a Comparison with Other Neurodevelopmental Disorders.

The aim of this study was to describe the profile of specific neonatal morbidities in children later diagnosed with autism spectrum disorder (ASD), and to compare this profile with the profile of children with hyperkinetic disorder, cerebral palsy, epilepsy or intellectual disability. This is a Danish population based cohort study, including all children born in Denmark from 1994, through 2010, and surviving the first year of life. Children with ASD as a whole have significantly elevated rates of a range of neurologic, respiratory, inflammatory, and metabolic problems in the neonatal period compared to the general population, but there are few if any indicators of a distinctive neonatal morbidity profile in ASD compared to other neurodevelopmental outcomes.

Iron status at 12 months of age -- effects of body size, growth and diet in a population with high birth weight.

OBJECTIVE: To investigate effects of growth and food intake in infancy on iron status at the age of 12 months in a population with high birth weight and high frequency of breast-feeding. DESIGN: In a longitudinal observational study infants' consumption and growth were recorded. Weighed 2 day food records at the ages of 6, 9 and 12 months were used to analyse food and nutrient intake. SETTING: Healthy-born participants were recruited from four maternity wards. Blood samples and growth data were collected from healthcare centres and food consumption data at home. SUBJECTS: Newborn infants (n=180) were selected randomly according to the mother's domicile and 77% (n=138) participated, of them, 83% (n=114), or 63% of original sample, came in for blood sampling. RESULTS: Every fifth child was iron-deficient (serum ferritin <12 microg/l and mean corpuscular volume<74 fl) and 2.7% were also anaemic (Hb<105 g/l). Higher weight gain from 0 to 12 months was seen in infants who were iron-deficient at 12 months (6.7+/-0.9 kg) than in non-iron-deficient infants (6.2+/-0.9 kg) (P=0.050). Serum transferrin receptors at 12 months were positively associated with length gain from 0 to 12 months (adjusted r(2)=0.14; P=0.045) and mean corpuscular volume negatively to ponderal index at birth (adjusted r(2)=0.14; P=0.019) and 12 months (adjusted r(2)=0.17; P=0.006). Iron-deficient infants had shorter breast-feeding duration (5.3+/-2.2 months) than non-iron-deficient (7.9+/-3.2 months; P=0.001). Iron status indices were negatively associated with cow's milk consumption at 9-12 months, significant above 460 g/day, but were positively associated with iron-fortified breakfast cereals, fish and meat consumption. CONCLUSIONS: : In a population of high birth weight, iron deficiency at 12 months is associated with faster growth and shorter breast-feeding duration from 0 to 12 months of age. The results suggest that a diet of 9-12-month-olds should avoid cow's milk above 500 g/day and include fish, meat and iron-fortified breakfast cereals to improve iron status.

Energy intake and growth of infants in Iceland-a population with high frequency of breast-feeding and high birth weight.

OBJECTIVE: To investigate infants' energy intake and growth in a population with a high frequency of breast-feeding and high birth weight. DESIGN: The infants' consumption was recorded once a month from 1 to 12 months of age. At the ages of 2, 4, 6, 9 and 12 months all ingested food was weighed accurately to calculate nutrient intake. A control group participated at the age of 9 months. SETTING: Participants, who were born healthy, were recruited from four different maternity wards. Growth data were collected from healthcare centres and consumption data with parents' assistance from the infants' homes. SUBJECTS: Infants (n=250) were randomly selected and divided into a research group (n=180) and a control group (n=70). The research group participants numbered 138 (77%) and the control participants 57 (81%). RESULTS: Energy intake was lower than current recommendations but was similar to that found in recent studies. Growth, as a percentage of birth weight, correlated negatively with birth weight, with r=0.77 (P<0.001) for growth to 12 months. Infants breast-fed at 7 months of age gained less weight from 6 to 9 months, 1057+/-58 g, than those not breast-fed, 1498+/-130 g (P<0.001). Analysis of the control group's intake showed that participation in the study did not affect intake. CONCLUSION: The findings support the need for new recommendations on energy intake and new growth charts based on current knowledge about breast-fed infants. Birth weight is a determining factor of growth in infancy, and percentage weight gain during the first year of life increases as birth weight decreases. SPONSORSHIP: The Icelandic Research Council, The Research Fund of the University of Iceland, The Icelandic Nutrition Council, The Students' Innovation Fund, The Icelandic Dairy Marketing Board

[Persistent organochlorines in Icelandic breast milk.].

Persistent organochlorines are passed from a mother to her offspring and can affect his or her growth and development. The levels of persistent organochlorines in breast milk from 22 Icelandic women (18 primiparae and four bisparae) were investigated during the summer of 1993. The samples were collected at the Maternity Department of Landspitalinn, the University Hospital in Reykjavik. Dichloro-diphenyl-dichlorethene (DDE), hexachlorobenzene (HCB) and polychlorinated biphenyls (PCBs), were found in all samples but not hexachlorocyclohexane (HCH). No statistical difference was found between primi- and bisparae mothers. The levels found were similar to what has been reported for breast milk in neighbouring countries in recent years and lower than was found in France, Germany, Italy and among Inuits of arctic Canada but higher than was found in mothers from South-Canada and Great Britain. The levels, however, were well below estimated risk levels for infants.