Human sex ratios and sex distribution in sibships of size 2

We previously analyzed data from the U.S. National Health Interview Survey (NHIS, 1998 to 2002) on families with two biological children (10 years of age and younger) and found that the distribution of families with two boys, two girls, and one boy + one girl did not statistically conform to a binomial distribution regardless of the boy/girl sex ratio used. Using the best estimate of the sex ratio from the data, we found that there were significantly more families with opposite-sex siblings than families with same-sex siblings. No biological mechanism could explain these results at the time. In the present study we conducted an analysis of the first two children in sibships of size 3 from the same data source and found that there are significantly more same-sex sibships than unlike-sex sibships. Combining the two sets of data for the first two children produced observed numbers in close agreement with the expected numbers. A hypothesis of parental choice (family planning) appears to be strongly supported as an explanation for the discrepancies in the two sets of data individually. For example, parents who have a boy and a girl (either order) as their first two children are more likely to stop having children ("stopping rule") than are parents whose first two children are of the same sex.     

Sex ratio at birth in India, its relation to birth order, sex of previous children and use of indigenous medicine

Objective

Sex-ratio at birth in families with previous girls is worse than those with a boy. Our aim was to prospectively study in a large maternal and child unit sex-ratio against previous birth sex and use of traditional medicines for sex selection.

Main Outcome Measures

Sex-ratio among mothers in families with a previous girl and in those with a previous boy, prevalence of indigenous medicine use and sex-ratio in those using medicines for sex selection.

Results

Overall there were 806 girls to 1000 boys. The sex-ratio was 720∶1000 if there was one previous girl and 178∶1000 if there were two previous girls. In second children of families with a previous boy 1017 girls were born per 1000 boys. Sex-ratio in those with one previous girl, who were taking traditional medicines for sex selection, was 928∶1000.

Conclusion

Evidence from the second children clearly shows the sex-ratio is being manipulated by human interventions. More mothers with previous girls tend to use traditional medicines for sex selection, in their subsequent pregnancies. Those taking such medication do not seem to be helped according to expectations. They seem to rely on this method and so are less likely use more definitive methods like sex selective abortions. This is the first such prospective investigation of sex ratio in second children looked at against the sex of previous children. More studies are needed to confirm the findings.     

Influence of variation in birth weight within normal range and within sibships on IQ at age 7 years: cohort study

ObjectiveTo examine the relation between birth weight and measured intelligence at age 7 years in children within the normal range of birth weight and in siblings.DesignCohort study of siblings of the same sex.Setting12 cities in the United States.Subjects3484 children of 1683 mothers in a birth cohort study during the years 1959 through 1966. The sample was restricted to children born at ⩾37 weeks gestation and with birth weights of 1500-3999 g.ResultsMean IQ increased monotonically with birth weight in both sexes across the range of birth weight in a linear regression analysis of one randomly selected sibling per family (n= 1683) with adjustment for maternal age, race, education, socioeconomic status, and birth order. Within same sex sibling pairs, differences in birth weight were directly associated with differences in IQ in boys (812 pairs, predicted IQ difference per 100 g change in birth weight =0.50, 95% confidence interval 0.28 to 0.71) but not girls (871 pairs, 0.10, −0.09 to 0.30). The effect in boys remained after differences in birth order, maternal smoking, and head circumference were adjusted for and in an analysis restricted to children with birth weight ⩾ 2500 g.ConclusionThe increase in childhood IQ with birth weight continues well into the normal birth weight range. For boys this relation holds within same sex sibships and therefore cannot be explained by confounding from family social environment.

What is already known on this topic

IQ at school age is linked to birth weight among low birthweight babiesSome evidence suggests the association might also apply to children of normal birth weight

What this study adds

IQ at age 7 years is linearly related to birth weight among children of normal birth weightThe relation was not due to confounding by maternal or socioeconomic factorsIQ is also associated with differences in birth weight between boy sibling pairs but not girls     

Sex Differences in Obese Children and Siblings in Family‐based Obesity Treatment

Objective: The primary goal was to evaluate sex differences in child weight control programs that targeted increasing physical activity (increase) or the combination of reducing sedentary behavior and increasing physical activity (combined). A second goal was to evaluate the benefits of family‐based interventions on nontargeted siblings. Research Methods and Procedures: Sixty‐seven families with obese children and 89 siblings were randomized to interventions that targeted increasing physical activity (increase) or the combination of reducing sedentary behavior and increasing physical activity (combined). Targeted participants and nontargeted siblings were followed for 1 year. Results: At 12 months, boys showed significantly better percentages of overweight changes (?15.8%) for the combined treatment than girls (?1.0%), with no significant differences for the increase intervention for boys (?9.3%) or girls (?7.6%). Boys adhered to treatment better than girls (p < 0.01). Adherence and predilection for physical activity were significant predictors of targeted child weight loss at 1 year in multiple regression analysis. Predictors of sibling weight loss included age, number of siblings, targeted child percentage of overweight change, and the interaction of group assignment by same sex of treated sibling. Discussion: Gender may influence response to programs that attempt to decrease sedentary behavior, and generalization of treatment effects to siblings may depend on the intervention and characteristics of the siblings.     

Study of Childhood Urinary Tract Infection in General Practice

A study of bacteriuria was conducted among 426 of the 436 children under the age of 13 in a general practice in north-west London. Three girls and one boy were found to have asymptomatic bacteriuria, and a further girl with bacteriuria presented with abdominal pain and fever. The calculated incidence of urinary tract infection was 1·4% per annum. Most of the childhood urinary infections in this practice occurred before the age of 5 years, and the incidence of significant bacteriuria in this age group was 4·9% per annum. Five other children (four girls and one boy) in the practice were known to have had proved urinary tract infection. Of the total of eight children known to have had significant bacteriuria and investigated radiologically, three girls and two boys had radiological abnormalities in the urinary tract.Pyuria and proteinuria did not prove to be useful in the prediction of asymptomatic bacteriuria. Urinary tract infection with renal tract abnormality was found in this practice to be at least five times as common as diabetes in childhood.     

Causes of precocious puberty in children referred for evaluation in hospital conditions

INTRODUCTION: Symptoms of precocious puberty (PP) in children always arouse anxiety in their parents. Many children with PP are being hospitalized for the detailed diagnostic work-up. The aim of our study was to analyze the frequency of the variants of PP in children referred to our department. MATERIAL: Retrospective analysis of 119 children (103 girls and 16 boys) referred for hospitalization in the years 2003-2005 due to signs of precocious puberty was performed. RESULTS: Premature thelarche, benign variant of puberty, was diagnosed in 62 (53%) girls, in the mean age of 3.39 (+/- 2.33) years. Their mean height was within 0.7 +/- 1.1 SD. Premature pubarche was diagnosed 30 (25%) children--22 girls and 8 boys in the mean age was 7.24 (+/- 0.81) years. Their mean height was 1.3 +/- 1.0 SD and was significantly higher than normal (p < 0.0001). Premature menarche was diagnosed in 8 (7%) girls in the mean age 4.81 +/-2.26 years. Mean height in this group was normal for age (0.9+/-0.8 SD). PP was diagnosed in 19 (16%) children (11 girls and 8 boys) in the mean age 5.91 +/- 1.63 years. Mean height in this group was 1.6 +/- 0.7 SD, and was significantly higher than the mean for age (p<0.0005). GnRH-dependent type was present in 15 children, diagnosed as idiopathic in 9 girls and 1 boy. In 5 children (4 boys and 1 girl) pathology of central nervous system was found. In 4 children GnRH-independent precocious puberty was diagnosed--in 3 caused by congenital adrenal hyperplasia and in 1 boy by tumour of testis (leydigioma). CONCLUSIONS: Girls with precocious thelarche without growth acceleration present the benign variant of puberty and need clinical follow up only. Boys with clinical signs of precocious puberty should be carefully evaluated to rule out the organic cause.     

Speech in same- and different-sex twins 4 and 5 years old.

The purpose of this study was to examine the impact of the sex makeup of pairs of twins on language acquisition. Past research indicated that this variable plays a role in speech problems of twin children. The questions raised were whether being a boy or a girl and having a boy or girl co-twin affected linguistic performance. A language test was given to 30 pairs of boy-girl twins, 16 pairs of boy twins, and 16 pairs of girl twins whose average age was 4 years 8 months. Their test scores confirmed our hypotheses. The poorest performance was obtained by the boy twin pairs and the best performance, by either the girl twin pairs or the different-sex pairs. The results were interpreted in the light of findings on language learning differences between girls and boys, and also in terms of Vygotsky's zone of proximal development.     

Elevated blood pressure in school children and adolescents--prevalence and associated risk factors

Elevated blood pressure (BP) in children and adolescents is determined on normative distribution of BP in healthy children. The aim of this study was to determine prevalence of high normal and elevated BP among school children and to assess associated risk factors. The study comprised 965 children (48.7% girls) in 8th grade of primary school. Data were obtained from questionnaire and anthropometric measurements. The prevalence of high normal BP was 28.5% in girls, 36.8% in boys, and elevated BP 7.9% in girls and 5.3% in boys. Overweight was present in 19.4% of girls and 9.3% boys with high normal, and 29.7% of girls and 30.8% boys with elevated BP. Hypertension in family history was the most common associated factor reported by boys and girls with high normal and elevated BP. Follow-up of children throughout school age makes possible taking of preventative measures and promotion of healthy life style.     

Heights and weights of Da-an boys: did sisters really make a difference?

This study further examined the negative association between boys' growth and the presence of sisters within a relatively affluent community in Taipei, Taiwan. Among 596 boys born in 1976-77, differences in height and log-transformed weight were judged using analysis of covariance (ANCOVA) with measurement age as a covariate, and parental education level (four levels), number of sisters (0, 1, 2 or 3+) and number of brothers (0, 1, 2+) as predictors. The relative importance of birth order and sibling sex was examined among the near majority of boys with one sibling (47%, 278/596). The sibling composition variable was defined using mutually exclusive categories representing individuals with one sibling: either one older or younger brother or sister. All boys contributed information before leaving middle school at a mean age of 14.9 +/- 0.4 years SD. The results were compared with similar analyses of data for 154 of these same boys for whom measurements were available from primary school entry at a mean age of 64 +/- 0.3 years SD onward. Results were also compared with data for a cohort of 153 boys who entered primary school later in 1986. Results confirm that boys from the Da-an area born in the mid-1970s who did not have sisters were significantly taller (2.2-2.5 cm, p < or = 0.008) and heavier (3.0-3.9 kg, p < or = 0.016) than those with one or two sisters. However, the 26 boys with three or more sisters, most of whom were last-born, were somewhat taller than those with one or two sisters. The same curvilinear relationships in height and weight appeared both among boys as they prepared to leave middle school and among the subset also measured just after entering primary school. When numbers of sisters were statistically controlled, the presence of two or more brothers was also significantly negatively associated with mean stature, but not weight, among middle school boys. Analyses among boys with one sibling revealed that birth order was associated with mean stature, but only if the sibling was female; an older sister was associated with a greater deficit in mean stature than a younger sister. Evidence of rising educational expectations, continued declines in family size with fewer gender-related differences in numbers of siblings, and a clear secular increase in body size in this community among children entering primary school from 1982 to 1986 suggest a possible explanatory model.     

Measles Case Fatality Rate in Bihar,India, 2011–12

Background

Updated estimates of measles case fatality rates (CFR) are critical for monitoring progress towards measles elimination goals. India accounted for 36% of total measles deaths occurred globally in 2011. We conducted a retrospective cohort study to estimate measles CFR and identify the risk factors for measles death in Bihar–one of the north Indian states historically known for its low vaccination coverage.

Methods

We systematically selected 16 of the 31 laboratory-confirmed measles outbreaks occurring in Bihar during 1 October 2011 to 30 April 2012. All households of the villages/urban localities affected by these outbreaks were visited to identify measles cases and deaths. We calculated CFR and used multivariate analysis to identify risk factors for measles death.

Results

The survey found 3670 measles cases and 28 deaths (CFR: 0.78, 95% confidence interval: 0.47–1.30). CFR was higher among under-five children (1.22%) and children belonging to scheduled castes/tribes (SC/ST, 1.72%). On multivariate analysis, independent risk factors associated with measles death were age <5 years, SC/ST status and non-administration of vitamin A during illness. Outbreaks with longer interval between the occurrence of first case and notification of the outbreak also had a higher rate of deaths.

Conclusions

Measles CFR in Bihar was low. To further reduce case fatality, health authorities need to ensure that SC/ST are targeted by the immunization programme and that outbreak investigations target for vitamin A treatment of cases in high risk groups such as SC/ST and young children and ensure regular visits by health-workers in affected villages to administer vitamin A to new cases.     

Health behaviours of school children in northwestern Poland in 2000

The 3568 final class primary school in northwestern Poland were investigated between January and June 2000. The youths fulfilled the questionnaire concerned health behaviour issues. The 56% of school children do not drink milk daily, 68% do not eat raw vegetables, and 35% do not take any food at school. Every second boy and every fourth girl brushes his/her teeth too rarely. 23% of boys and 10% of girls smoke cigarettes. About 30% of boys and 20% of girls declare that it “happens” that they drink alcohol. 15% boys and 8% of girls report that they tried to use at least one of the psychoactive substances. Physical exercises are performed by 28% of boys and 36% of girls and 45% and 28% respectively watch TV four or more hours a day.     

Estimating final height from parental heights and sex in Taiwanese

We have developed a simple function for accurately estimating target height for use in evaluating growth and growth-promoting therapies in Taiwanese children. The heights of parents and their adult offspring born in the 1970s were determined in 1229 healthy families who accompanied another family member to our pediatric clinic. We directly measured the heights of the population-based cohort of adult offspring. The heights of their parents were based on self-report. Both the parents and their offspring were healthy. The increases in height between the two generations were 1.49-3.19 cm for boys and 2.03-2.61 cm for girls. These increases lie between those reported for Chinese children in Hong Kong (4.2-4.8 cm) and children in Sweden (0.7-1.0 cm). Final height was underestimated using the corrected midparental height method and was overestimated using the final parental height model developed from Swedish data. We developed a new linear model by fitting our data: boy height = 79.3 + 0.56 (midparental height); girl height = 35.2 + 0.76 (midparental height). The intercept and slope of the model are similar to those reported for Swedish girls but not to those reported for Swedish boys. Use of the new equations derived from our data may increase the accuracy of estimates of target height in Taiwanese children. The intermediate position of our fairly representative Taiwanese sample in both final height and generational increases in final height may reflect an intermediate stage between the Swedes and Hong Kong Chinese in the secular trend of heights.     

Hereditary angioneurotic edema and Charcot-Marie-Tooth disease in the same family.

In one family two genetic diseases were transmitted as autosomal dominant traits; hereditary angioneurotic edema was inherited from the paternal side and Charcot-Marie Tooth disease from the maternal side of the family. The conditions occurred separately in 8 and 11 members respectively and together (an exceedingly rare occurrence) in 3. Of six siblings, two girls and four boys, all had Charcot-Marie-Tooth disease, and three, the two girls and one of the boys, also had hereditary angioneurotic edema.     

Social and Individual Components of Animal Contact in Preschool Children

ABSTRACT

Humans are generally biophilic. Still, for unknown reasons, interest in animals varies substantially among individuals. Our goal was to investigate how differential interest of children towards animals might be related to social competence and personality. We proposed two alternatives: 1) Children may compensate for potential deficits in social competence by resorting to animals, and 2) Socially well-connected children may show a particular interest in animals. We focused on relationships between age, gender, family background, play behavior, personality components, and contact with rabbits in 50 children (22 boys/28 girls; 3 to 7 years of age) at a preschool in Krems/Austria. Data were analyzed using GLM. We found that each one of these variables had significant impact on intensity of engagement with the rabbits. In general, girls, children with siblings, and children without pets were more oriented towards the rabbits than were boys, children without siblings, or pet-owning children. The older the children, the less frequently they occupied themselves with the rabbits but the longer they remained when they did engage them. Furthermore, we found that the more “Confident/Respected” (PCA factor 1) and less “Patient/Calm,” “Cheerful/Sociable,” and “Solitary” (PCA factors 2–4) the children, the more time they spent in direct occupation with rabbits. Most effects of the investigated variables varied between boys and girls. By and large, our findings support the hypothesis that the “socially competent” children were particularly interested in the animals. Also, children's social styles, as evinced in interactions with peers, were generally reflected in how they interacted with the rabbits.     

High rate of Helicobacter pylori reinfection in children and adolescents

AIMS: Primary Helicobacter pylori infection occurs predominantly in childhood. The aims of this study were to establish the rate of H. pylori reinfection after successful eradication in children and adolescents and to determine the risk factors associated with reinfection. PATIENTS AND METHODS: This retrospective study involved 45 children (20 girls, 25 boys) who met the following criteria: eradication of H. pylori confirmed at least 4 weeks after the completion of therapy, and the search for reinfection at least one year after control of eradication of H. pylori. Demographic data, socioeconomic status and living conditions were recorded. RESULTS: Forty-five children aged 1.2-17.6 years (median, 10.9 years) at the time of H. pylori treatment were reviewed 1 to 9 years after H. pylori eradication. Eight children (18%) had been reinfected (5.4% to 6% per patient-year). Six of 25 (24%) children older than 10 years at the time of diagnosis became reinfected. None of the studied risk factors was associated with reinfection. However, having a sibling younger than 5 years was found in four of seven (57%) reinfected children versus five of 24 (21%) nonreinfected children (p = .08). CONCLUSION: Children become reinfected more frequently than adults. Adolescents become reinfected, whereas acquisition of primary H. pylori infection occurs predominantly in early childhood. Close contact with young children, especially siblings, younger than 5 years could be a more important risk factor than the age of the patient at the time of treatment for the high rate of reinfection in childhood.     

Critical assessment of the use of growth monitoring for identifying high risk children in primary health care programmes.

OBJECTIVE--To see whether change in weight was a more useful index than weight for age in assessing the risk of dying among malnourished children. DESIGN--Prospective cohort study. SETTING--Rural community in Bangladesh being served by international health organisation. PARTICIPANTS--1011 Children aged under 5, of whom 66 died. END POINT--Efficient screening method for identifying malnourished children at risk of dying. MEASUREMENTS AND MAIN RESULTS--Weight was measured every month. Weight for age and monthly change in weight averaged over one and three months were calculated. Sensitivity and specificity curves were used to compare the values of these two variables in identifying children with a high risk of dying. Weight for age was more sensitive than change in weight at all levels of specificity. Changes in weight, however, were independently related to the risk of dying even when intercurrent diseases and low weight for age were taken into account. CONCLUSIONS--For identifying children with a high risk of dying weight for age is a more efficient screening tool than a recent change in weight. Growth monitoring as currently recommended for primary health care programmes in developing countries does not seem to be the most effective approach in identifying children in need of urgent help.     

A family with x-linked hydrocephaly followed for 20 years: echographic prenatal diagnosis; elective abortion

In a Bickers-Adams family followed up for almost 20 years, authors report pregnancies of two propositus' sisters: echographic diagnosis of (normal) girls, of normal or affected boys and selective abortion in a case of dizygotic twin pregnancy with a normal girl and an affected boy.     

Swedish experience of two dose vaccination programme aiming at eliminating measles,mumps, and rubella.

In 1982 a two dose regimen was introduced in Sweden for the combined vaccination against measles, mumps, and rubella of children aged 18 months and 12 years. Since 1977 about half of the preschool children were vaccinated against measles annually, and since 1974 about 80% of 12 year old girls were vaccinated against rubella. During the period 1982 to 1985 90-93% of the eligible age cohorts of 18 month old children and 88-91% of the 12 year old children were immunised with the new combined vaccine. A study in 1982 of about 140 18 month old children who were nearly all seronegative before vaccination showed that 96%, 92%, and 99% seroconverted against measles, mumps, and rubella, respectively. A second study was carried out in 1983 of 247 12 year old children, of whom 11% lacked antibodies to measles, 27% to mumps, and 45% to rubella. This showed seroconversion in 82% and 80% against measles and mumps, respectively, and all children seroconverted against rubella. In the latest study in 1985 of 496 12 year olds 9% and 13% were seronegative against measles and mumps before vaccination, and 41% against rubella. Of these, 88% seroconverted to measles and 80% to mumps, and all converted to rubella when sera were tested by the haemolysis in gel method. After a neutralisation test against measles as well all children showed immunity to the disease. A low incidence of measles and declining figures for mumps and rubella were reported in 1984 to 1986. An outbreak of rubella during 1985 affected mainly boys in age cohorts in which only the girls had been vaccinated during the 1970s.     

Seroprevalence of measles-, mumps- and rubella-specific IgG antibodies in german children and adolescents and predictors for seronegativity

We have undertaken a seroprevalence study with more than 13,000 children, who had been included in the German KIGGS survey, a representative sample of children and adolescents 0-17 years of age. The IgG titres against measles, mumps and rubella were determined in 1 to 17 year olds While 88.8% of the children were MMR-vaccinated at least once, 76.8% of children aged 1 to 17 years showed prevalence of antibodies to MMR. The highest seronegativity was seen with respect to mumps. Gender differences were most pronounced with regard to rubella IgG titres: girls aged 14 to 17 years were best protected, although seronegativity in 6.8% of this vulnerable group still shows the need of improvement. Search for predictors of missing seroprevalence identified young age to be the most important predictor. Children living in the former West and children born outside of Germany had a higher risk of lacking protection against measles and rubella, while children with a migration background but born in Germany were less often seronegative to measles antibodies than their German contemporaries. An association of seronegativity and early vaccination was seen for measles but not for mumps and rubella. A high maternal educational level was associated with seronegativity to measles and rubella. In vaccinated children, seronegativity was highest for mumps and lowest for rubella. For mumps, high differences were observed for seronegativity after one-dose and two-dose vaccination, respectively. Seronegativity increases as time since last vaccination passes thus indicating significant waning effects for all three components of MMR.     

Kin detection cues and sibling relationship quality in adulthood: The role of childhood co-residence duration and maternal perinatal association

Cues facilitating kin detection among children have been suggested to have a profound impact on adult sibling relationships. Using a large and population-based data of younger and middle-aged Finns, we test how childhood co-residence duration and maternal perinatal association (MPA) correlate with contact frequency, emotional closeness and provision of help between adult siblings. Employing sibling fixed-effect regression models we show that duration of co-residence in childhood and MPA are indeed associated with better relationship quality in all three measures. Provided MPA, sibling relationship quality is high independently of co-residence length, but in the absence of MPA, increased co-residence duration is associated with better relationship quality. Co-residence duration is more strongly associated with provision of help between opposite-gender than same-gender sibling dyads. Full siblings report better relationship quality than half siblings do, although the co-residence duration mediates the effect of genetic relatedness in emotional closeness between full and maternal half siblings and in provision of help between full and paternal half siblings. Moreover, MPA serves as a mediator in the case of emotional closeness between full and maternal half siblings. Our results provide solid support for the importance of childhood kin detection cues for sibling relationship quality in adulthood, and how such cues interact with genetic relatedness and gender.