Late effects of breast-feeding and early weaning: seven-year prospective study in children.

The effect of breast feeding on some clinical and thyroid function parameters was studied in a prospective longitudinal study from birth up to 7 years of age. At the ages 1-7 years, the obesity rates observed in children breast-fed for less than 3 months were substantially higher than in children who had been breast-fed over longer intervals. Mean age when obesity was reported was similar in all groups (4-5 years). The rates of respiratory tract diseases were found to be highest in children which had been breast-fed for less than 2 weeks. Breast-feeding for more than 6 months had a protective effect against diseases of the gastrointestinal tract. The longitudinal follow-up revealed biphasic changes of thyroid hormones and TSH in sera with a nadir at 2-3 years, followed by an increase at the end of preschool age. Duration of breast-feeding did not affect profoundly these parameters at the ages 1-7 years. Surprisingly, during late preschool age (5-6 years) total serum cholesterol increased with the age at weaning. The atherogenic index in 6-year-old children was most favourable in the group breast-fed over more than 1 but less than 3 months. This was due to the highest levels of HDL-cholesterol in this group. We conclude that the age at weaning may be important for the later development of children.

[Lipoprotein profiles in 6-year-old children breast fed for different periods of time]. / Lipoproteínový profil sestrocných detí s rôznou dojceneckou výzivou.

The authors submit results of investigations of the lipoprotein profile in six-year-old children fed a different diet during infancy. It is the continuation of previous results of a long-term longitudinal investigation of this group of healthy children which revealed a favourable effect of breastfeeding on the cholesterol distribution in lipoprotein fractions. Throughout the investigation the children were divided into four groups according to the breastfeeding period. At the age of six serum cholesterol was assessed and cholesterol in lipoprotein fractions, levels of apolipoproteins A1 and B and risk for the genesis and development of atherosclerosis were calculated. The most favourable lipoprotein profile was found in the group of children, breastfed for three months and with this corresponded also the lowest values of the risk indexes. The serum cholesterol concentration, levels of serum apolipoproteins A1 and B in different groups of children did not differ significantly.

[Pfeiffer's syndrome]. / Pfeifferov syndróm.

The authors examined a 2-month-old infant with clinical signs of Pfeiffer's syndrome (craniosynostosis, abnormalities of the extremities, normal psychomotor development). In the family other affected cases were revealed with a variable expressivity of the clinical signs. The authors draw attention to the importance of a detailed clinical, X-ray and anthropometric examination of different members of the family to detect carriership of the gene for ACS.

[The effect of different types of infant nutrition on indicators of lipid metabolism in 1-to-4-year-old children]. / Vplyv rôznej dojcenskej výzivy na niektoré ukazovatele tukového metabolizmu diet'at'a v období od 1. do 4. roka zivota.

The authors present the results obtained in investigations of the influence of different infant diets on some indicators of lipid metabolism in a group of healthy children followed up from birth and aged 1-4 years at the time of the investigation. The work is a continuation of previous investigations which provided evidence of the influence of breastfeeding on blood lipid levels and the cholesterol distribution in different lipoprotein fractions during the early postnatal period. The analysis of the plasma cholesterol and lipoprotein cholesterol in children breastfed for varying periods and children not breastfed bottlefed) at the age of 1, 1.5 and 2 years did not reveal substantial differences. The percentage ratio of cholesterol in different lipoprotein fractions in children aged 2 years and the risk indexes were, however, more favourable in children breastfed for the longest period. Similar results were recorded also in children aged 4 years. The apolipoprotein B plasma level which was assessed by immunoelectrophoresis was throughout the investigation higher in bottlefed children although the differences were not statistically significant.

Effect of breast-feeding on infant thyroid activity: 3 year follow up--longitudinal study.

The effect of breast-feeding on serum thyroid hormones and TSH was studied in a longitudinal study from birth up to 3 years. T4 was found to be significantly higher in breast-fed than in weaned infants at the age of 4 and 6 months and so was rT3 at the age 4 months. The body weight of breast-fed girls at the age 4 and 6 months was lower than that of formula-fed ones. Breast-feeding at the age 9 months resulted in a decreased serum TSH. Serum T3 of infants weaned before the end of the first week of life was higher than in other groups of infants at the age of 10 weeks. Serum T4 of children 1-2-year-old correlated positively with the age at weaning, provided that they had been breast-fed at least for 60 days. Serum rT3 of 2-year-old children also correlated with the age of weaning. Serum TSH at the age of 3 years was higher in children who had been weaned during first 60 days of life than in those weaned later. It is concluded that breast-feeding possess some immediate effects on thyroid function parameters. Some effects were still detected at the age of 1-3 years.

Thyroid hormones in milk: physiological approach--a review.

Reported values of the concentration of thyroid hormones in milk vary substantially. There are some doubts on the specificity of methods used for their estimation. We aimed, therefore, to study the effects of mother milk on thyroid function parameters in sucklings as well as at the effect of milk secretion on maternal thyroid. According to Fukuda et al. [1980] the lactation induces a hypothyroid state in the rat (high TSH, low thyroid hormones in maternal plasma). In our study the weaning of 18-day old rats resulted in gradual decrease of T4 in suckling plasma through 24 h followed with a transient thyroid activation. Thyroidectomy of lactating rats resulted in a transient decrease of T4 in sucklings. The difference in mother milk intake achieved by different litter size also affected the thyroid function of sucklings. The pups from small size litters (more milk consumption) had low thyroid secretion rate and low plasma TSH, while the level of T4 in plasma was high under a higher growth rate and accelerated overall maturation. All these results suggest an exogenous intake of thyroid hormones in suckling rat. We found that lactation in women resulted in lower T4 and higher TSH in plasma as compared to women who had interrupted their lactation. In the next part of our study more than 80 infants were longitudinally followed and sampled at birth (cord blood), at 2, 6 and 10 weeks and at 4, 6, 9 and 12 months. Only moderate differences were found at 4 months (high rT3) in breast fed infants and 9 at months (high T3 in plasma of infants weaned during the first week of life) when the data were evaluated according to the type of feeding. Thyroid activity of human milk was tested by feeding thyroidectomized rats with a diet containing human milk. Although plasma TSH was affected by such a diet, we did not detect any T4 and T3 in plasma of thyroidectomized rats which probably refects low calculated intake of hormones with the diet. We conclude that the lactation affects the thyroid economy of maternal organisms. Maternal milk definitely affects thyroid function parameters in the rat, while the effect on infant thyroid is more difficult to demonstrate.

Thyroid activity in early weaned and suckling infants and their lactating mothers.

The activity of thyroid gland was estimated in a group of lactating mothers and their suckling infants as well as in a group of early weaned infants. In both groups of infants the same level of thyroxine and triiodothyronine was found, but it was higher than that in mothers. The binding properties of specific plasma proteins and free thyroxine index were the same in both groups of infants. The level of TSH in serum of suckling infants (4.7 +/- 0.5 microunits ml-1) was significantly higher (P less than 0.01) than that in weaned infants (3.0 +/- 0.3 microunits ml-1). The level in mothers (4.0 +/- 0.3 microunits ml-1) did not differ significantly from that in both groups of infants. A positive correlation was found between the level of TSH in lactating mothers and their suckling infants (r = +0.494, P less than 0.05). The data suggest that the regulation of thyroid activity in infants may be affected by suckling.

Thyroxine (by competitive protein binding analysis) in human and cow milk and in infant formulas.

In 45 mothers of full term infants the level of thyroxine (T4) in serum (45 samples) and unskimmed milk (92 samples) was estimated with the aid of competitive protein binding analysis. On the 3rd day after delivery the T4 level in serum was found to be 11.1 +/- 0.4 mug/100 ml, while that in milk was 1.3 +/- 0.3 mug/100 ml. During following days of lactation the T4 concentration in sera decreased. In contrast, however, a gradual increase of the T4 content in milk was observed. The serum and milk levels equalized during the third week post partum (7.3 +/- 1.3 and 7.6 +/- 1.4 mu6/100 ml, respectively). After the 25th day the T4 level in milk was found to be higher than in sera from the same women (paired test: P less than 0.005). Values of 12.9 +/- 1.3 in milk and 8.1 +/- 0.7 mug/100 ml in sera were found in the second month of lactation. A negative correlation between serum and milk T4 level was found during the early lactation (3-20 days), while after 20th day this correlation was positive. Very low and almost undetectable levels of T4 were found in cow's milk and infant formulas derived from it.