Childhood infections and adult height in monozygotic twin pairs

Associations between early infections and childhood cognition in the Newcastle Thousand Families Study birth cohort

Childhood infections have been shown to stunt growth, contribute to malnutrition and reduce cognition in early adulthood. This study aimed to assess relationships between early life infections and childhood cognition at age 11 years in the Newcastle Thousand Families Study (NTFS). The analysis included 741 members from the NTFS who had complete data for infections between birth and 5 years, and the 11-plus examinations. School records from the 11-plus examinations showed cognitive (IQ), English (EQ) and arithmetic (AQ) abilities. Housing conditions, overcrowding, birth order and social class were recorded at birth. Helicobacter pylori seropositivity was measured at age 49-51 years. Multivariable linear regression was used to examine relationships between infections and cognition. The total number of infections in the first 5 years of life was not significantly associated with IQ, EQ or AQ, nor were there significant relationships between cognitive outcomes and most infections. Tonsillitis did display a positive, significant association with IQ after adjustment for confounders (b = 6.43, 95% CI 0.92, 11.94, p = 0.022). Lower respiratory tract infections (LRTIs) showed significant negative relationships with all cognitive outcomes. H. pylori seropositivity at age 50 exhibited negative, significant relationships with EQ (p = 0.014) and AQ (p = 0.024) after adjustment for confounders. Although no significant relationship between overall infections and cognition were found, there were indications that LRTIs and gastrointestinal system infections may limit cognitive development. Given these infections remain prevalent, further research regarding severity and recurrence of infections and how they affect childhood cognition is needed.

What is driving the relationship between height and cognition? Evidence from the Twins Early Development Study

Taller children tend to have better cognitive ability, and the relationship between height and cognition has been proposed as an explanation for the height-wage labor market premium. Height-cognition associations may arise due to social factors that favor taller individuals or be driven by "common factors" that are correlated with height and cognition. Indeed, there is now evidence of a genetic correlation between height and cognition that provides specific evidence for this concern. We examine whether genetic factors explain the relationship by estimating associations between childhood height and cognition in the Twins Early Development Study. We find that height is associated with better cognition even after controlling for genetic and environmental factors shared by twins. The association between height and cognition within fraternal twin pairs is also robust to controlling for individual genetic predictors of height and cognition. These results suggest that genetic factors are not solely responsible for driving the relationship between height and cognition.

Childhood infections and autism spectrum disorders and/or intellectual disability: a register-based cohort study

Objective

To explore the associations between childhood infections and subsequent diagnoses of autism spectrum disorder (ASD), intellectual disability (ID), and their co-occurrence.

Methods

The association between specialized care for any infection, defined by ICD-codes, and later ASD or ID was investigated in a register-based cohort of 556,732 individuals born 1987–2010, resident in Stockholm County, followed from birth to their 18th birthday or December 31, 2016. We considered as potential confounders children’s characteristics, family socioeconomic factors, obstetric complications, and parental histories of treatment for infection and psychiatric disorders in survival analyses with extended Cox regression models. Residual confounding by shared familial factors was addressed in sibling analyses using within-strata estimation in Cox regression models. Sensitivity analyses with the exclusion of congenital causes of ASD/ID and documented risk for infections were also performed.

Results

Crude estimates indicated that infections during childhood were associated with later ASD and ID with the largest risks observed for diagnoses involving ID. Inclusion of covariates, exclusion of congenital causes of ASD/ID from the population, and sibling comparisons highlighted the potential for confounding by both heritable and non-heritable factors, though risks remained in all adjusted models. In adjusted sibling comparisons, excluding congenital causes, infections were associated with later “ASD without ID” (HR 1.24, 95%CI 1.15–1.33), “ASD with ID” (1.57, 1.35–1.82), and “ID without ASD” (2.01, 1.76–2.28). Risks associated with infections varied by age at exposure and by age at diagnosis of ASD/ID.

Conclusions

Infections during childhood may contribute to a later diagnosis of ID and ASD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11689-022-09422-4.

Do blind people share the tall-man stereotype?

The stereotype of a tall man has been reported in numerous studies. High stature is commonly associated with advantages such as leadership skills, wealth, intelligence or social status, and actual differences between the short and the tall men were indeed found for these traits, mainly in favor of the tall men. It is not certain, however, whether the height-related effects are biologically determined or if they result from socially-driven mechanisms. In this study we wanted to explore whether congenitally blind individuals, who are unable to perceive other people’s stature through the most salient, visual channel, share the positive, height-related stereotype. Thirty-four congenitally blind and forty-three sighted men and women rated four positive characteristics of a tall or a short man. It was found that none of the traits assigned to the tall man by the sighted people was assigned to this person by the blind individuals. In the congenitally blind group, no differences between the assessments of the tall and the short man were revealed. We discuss our findings in the context of social perception and stereotypes research.

Serratia marcescens as a cause of unfavorable outcome in the twin pregnancy

Several Serratia species are widely distributed in nature, but Serratia marcescens is the only species frequently isolated in hospitals. This pathogen is mainly responsible for nosocomial infection, mostly in immunocompromised hosts. A 26-year-old woman with a twin pregnancy, regularly controlled, was hospitalized at 24 + 5 weeks of gestation due to scant vaginal bleeding, lower abdominal pain, and body temperature up to 37.5°C. Gynecological examination revealed bleeding accompanied by dilatation of the cervix. The laboratory analyses revealed leukocytosis with elevated C-reactive protein (CRP). Treatment was initiated with intravenous antibiotic administration. After admission, fetal membranes spontaneously ruptured, and an extremely preterm dichorionic female twin birth occurred at 25 + 0 weeks of gestation. Both infants died two days after labor. Pathological and microbiological analyses revealed chorioamnionitis caused by S. marcescens. According to the antibiogram, antibiotic treatment was continued for the next 7 days. The examination of cervical and vaginal discharge samples was negative three days and two weeks after therapy. S. marcescens may cause spontaneous miscarriages and, in this important case, caused loss of discordant twins in an extremely preterm birth by an immunocompetent patient. Infection by S. marcescens cannot be excluded as a cause of discordant growth and needs to be confirmed by further research.

The association between obesity and secular trend of stature: a nationwide study of 2.8 million adolescents over five decades

BACKGROUND/OBJECTIVES

It is unclear whether adolescent obesity is associated with limited linear growth. We assessed this association in a nationwide sample of adolescents.

METHODS

We conducted a population-based, study of 2,785,227 Israeli adolescents (60% males) who were examined before military service since 1967 through 2015. Height and weight were measured along with assessment of medical status at age 17.4 ± 0.4 years. The secular trend of height was plotted using United States Center for Disease Control (US CDC) age- and sex-adjusted BMI percentile groups. We accounted for health status at enrollment and computed the expected height based on parental data that was available for 512,978 examinees.

RESULTS

Over five decades, the mean height increased by 3.1 cm among males, but remained unchanged among females. Among males, gain in height was attained predominantly during the first 25 years and has stabilized since. Males with obesity were taller than their normal-weight and underweight counterparts. Underweight girls had a prominent increase in mean height during the first two decades, exceeding the mean height of their counterparts with obesity by over 2 cm. There was a gradual decrease in the difference between measured and expected height in males and females regardless of BMI status, with the exception of the underweight females who achieved consistently higher stature than expected (≥3 cm).

CONCLUSIONS

During five decades, excessive BMI was not a limiting factor in growth potential compared with normal BMI in both sexes. The only group that exceeded its growth potential, when accounting for expected mid-parental height, were underweight females with unimpaired health.

Association of Childhood Infection With IQ and Adult Nonaffective Psychosis in Swedish Men: A Population-Based Longitudinal Cohort and Co-relative Study

IMPORTANCE

Associations between childhood infection, IQ, and adult nonaffective psychosis (NAP) are well established. However, examination of sensitive periods for exposure, effect of familial confounding, and whether IQ provides a link between childhood infection and adult NAP may elucidate pathogenesis of psychosis further.

OBJECTIVES

To test the association of childhood infection with IQ and adult NAP, to find whether shared familial confounding explains the infection-NAP and IQ-NAP associations, and to examine whether IQ mediates and/or moderates the childhood infection-NAP association.

DESIGN, SETTING, AND PARTICIPANTS

Population-based longitudinal cohort study using linkage of Swedish national registers. The risk set included all Swedish men born between 1973 and 1992 and conscripted into the military until the end of 2010 (n = 771 698). We included 647 515 participants in the analysis.

MEASUREMENT OF EXPOSURES

Hospitalization with any infection from birth to age 13 years.

MAIN OUTCOMES AND MEASURES

Hospitalization with an International Classification of Diseases diagnosis of NAP until the end of 2011. At conscription around age 18 years, IQ was assessed for all participants.

RESULTS

At the end of follow-up, the mean (SD) age of participants was 30.73 (5.3) years. Exposure to infections, particularly in early childhood, was associated with lower IQ (adjusted mean difference for infection at birth to age 1 year: -1.61; 95% CI, -1.74 to -1.47) and with increased risk of adult NAP (adjusted hazard ratio for infection at birth to age 1 year: 1.19; 95% CI, 1.06 to 1.33). There was a linear association between lower premorbid IQ and adult NAP, which persisted after excluding prodromal cases (adjusted hazard ratio per 1-point increase in IQ: 0.976; 95% CI, 0.974 to 0.978). The infection-NAP and IQ-NAP associations were similar in the general population and in full-sibling pairs discordant for exposure. The association between infection and NAP was both moderated (multiplicative, β = .006; SE = 0.002; P = .02 and additive, β = .008; SE = 0.002; P = .001) and mediated (β = .028; SE = 0.002; P < .001) by IQ. Childhood infection had a greater association with NAP risk in the lower, compared with higher, IQ range.

CONCLUSIONS AND RELEVANCE

Early childhood is a sensitive period for the effects of infection on IQ and NAP. The associations of adult NAP with early-childhood infection and adolescent IQ are not fully explained by shared familial factors and may be causal. Lower premorbid IQ in individuals with psychosis arises from unique environmental factors, such as early-childhood infection. Early-childhood infections may increase the risk of NAP by affecting neurodevelopment and by exaggerating the association of cognitive vulnerability with psychosis.

Body height and immune efficacy: testing body stature as a signal of biological quality

According to the good genes hypothesis and energy allocation theory, human adult body height may reflect biological quality. An important aspect of this quality is immune system functioning (ISF). The aim of this study was to evaluate the relationship between ISF and body height in healthy people. The ISF was determined by several important innate (total complement and lysozyme activity, neutrophil function) and adaptive immune parameters (lymphocytes, IgA and IgG, and response to the flu vaccine). Overall, 96 males and 97 females were subjected to flu vaccination, and of these, 35 males and 34 females were subjected to tetanus. Blood samples were collected before and four weeks after vaccination. Immunomodulatory factors, participant's age, body fat, and free testosterone levels, were controlled. There was no association between body height and all analysed immune parameters for both sexes. That might suggest that in Western society, a women's preference for taller men is not related to 'good genes for immune competence'. We propose the novel Immunity Priority Hypothesis that explains the lack of relationship between adult body stature and ISF. This hypothesis, however, does not contradict the signalling role of a man's body height as a morphological marker of biological quality.

Infection and pubertal timing: a systematic review

The decline in age of pubertal timing has serious public health implications ranging from psychosocial adjustment problems to a possible increase in reproductive cancers. One biologically plausible explanation for the decline is a decrease in exposures to infections. To systematically review studies that assess the role of infection in pubertal timing, Medline, Web of Science and EMBASE were systematically searched and retrieved studies were reviewed for eligibility. Eligible studies examined the association between infections, including microbial exposures, and physical pubertal characteristics (breast, genitalia and pubic hair development) or age at menarche. We excluded studies that were published in a language other than English, focused on precocious puberty, were case studies, and/or included youth with autoimmune diseases. We report on study design, population characteristics, measurement of infection and puberty and the main effects of infection on pubertal development. Based on our search terms we identified 1372 unique articles, of which only 15 human and five animal studies met our eligibility criteria. Not all studies examined all outcomes. Infection was associated with later breast development (4/4 human studies), with less consistent evidence for genitalia and pubic hair development. Seven studies assessed age at menarche with inconsistent findings (three supporting later, four no association). We conclude that a small but consistent literature supports that infection is associated with later breast development; the evidence for other pubertal events and age at menarche is less clear. Where fewer childhood infections coincide with the rise in incidence of hormone-related cancers.

Common immune-related exposures/conditions and risk of non-Hodgkin lymphoma: a case-control study of disease-discordant twin pairs

We evaluated the association between common immune system-altering experiences and non-Hodgkin lymphoma (NHL) risk using a case-control study of 162 like-sex twin pairs discordant for NHL, identified from the International Twin Study. Information on medical history and evidence of childhood exposure to microbes was obtained by questionnaire from 1998 to 2002. Conditional logistic regression was used to estimate odds ratios and 95% confidence intervals. Intra-twin-pair agreement between twins on individual exposures was high (76%-97%). A negative association between NHL and seasonal hay fever (odds ratio (OR) = 0.28, 95% confidence interval (CI): 0.10, 0.75) and certain allergies (OR = 0.29, 95% CI: 0.13, 0.68) was observed. The number of atopic diseases was negatively associated with NHL (P for trend = 0.0003). A history of infectious mononucleosis was negatively associated with NHL risk (OR = 0.35, 95% CI: 0.14, 0.90). NHL risk was associated with more frequent childhood exposure to microbes during early life (P for trend = 0.04). No differences in association by NHL subtype were observed, although statistical power for these comparisons was low. These observations support the hypothesis that immune-related exposures, especially atopy, are associated with decreased NHL risk. Use of the within-twin-pair study design mitigates confounding by genome, family structure, and unmeasured characteristics of early childhood factors.

A prospective study of height and body mass index in childhood, birth weight, and risk of adult glioma over 40 years of follow-up

Greater attained height and greater body mass index (BMI; weight (kg)/height (m)(2)) in young adulthood have been associated with glioma risk, but few studies have investigated the association with body size at birth or during childhood, when the brain undergoes rapid cell growth and differentiation. The Copenhagen School Health Records Register includes data on 320,425 Danish schoolchildren born between 1930 and 1989, with height and weight measurements from ages 7-13 years and parentally recorded birth weights. We prospectively evaluated associations between childhood height and BMI, birth weight, and adult glioma risk. During follow-up (1968-2010), 355 men and 253 women aged ≥18 years were diagnosed with glioma. In boys, height at each age between 7 and 13 years was positively associated with glioma risk; hazard ratios per standard-deviation score at ages 7 (approximately 5.1 cm) and 13 (approximately 7.6 cm) years were 1.17 (95% confidence interval (CI): 1.05, 1.30) and 1.21 (95% CI: 1.09, 1.35), respectively. No associations were observed for childhood height in girls or for BMI. Birth weight was positively associated with risk (per 0.5 kg: hazard ratio = 1.13, 95% CI: 1.04, 1.24). These results suggest that exposures associated with higher birth weight and, in boys, greater height during childhood may contribute to the etiology of adult glioma.

Risk of esophageal adenocarcinoma decreases with height, based on consortium analysis and confirmed by Mendelian randomization

BACKGROUND & AIMS

Risks for some cancers increase with height. We investigated the relationship between height and risk of esophageal adenocarcinoma (EAC) and its precursor, Barrett's esophagus (BE).

METHODS

We analyzed epidemiologic and genome-wide genomic data from individuals of European ancestry in the Barrett's and Esophageal Adenocarcinoma Consortium, from 999 cases of EAC, 2061 cases of BE, and 2168 population controls. Multivariable logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (95% CI) for associations between height and risks of EAC and BE. We performed a Mendelian randomization analysis to estimate an unconfounded effect of height on EAC and BE using a genetic risk score derived from 243 genetic variants associated with height as an instrumental variable.

RESULTS

Height was associated inversely with EAC (per 10-cm increase in height: OR, 0.70; 95% CI, 0.62-0.79 for men and OR, 0.57; 95% CI 0.40-0.80 for women) and BE (per 10-cm increase in height: OR, 0.69; 95% CI, 0.62-0.77 for men and OR, 0.61; 95% CI, 0.48-0.77 for women). The risk estimates were consistent across strata of age, education level, smoking, gastroesophageal reflux symptoms, body mass index, and weight. Mendelian randomization analysis yielded results quantitatively similar to those from the conventional epidemiologic analysis.

CONCLUSIONS

Height is associated inversely with risks of EAC and BE. Results from the Mendelian randomization study showed that the inverse association observed did not result from confounding factors. Mechanistic studies of the effect of height on EAC and BE are warranted; height could have utility in clinical risk stratification.