Smoking habit from the paternal line and grand-child's overweight or obesity status in early childhood: prospective findings from the lifeways cross-generation cohort study

High paternal homocysteine causes ventricular septal defects in mouse offspring

Maternal hyperhomocysteinemia is widely considered as an independent risk of congenital heart disease (CHD). However, whether high paternal homocysteine causes CHD remains unknown. Here, we showed that increased homocysteine levels of male mice caused decreased sperm count, sperm motility defect and ventricular septal defect of the offspring. Moreover, high levels of paternal homocysteine decrease sperm DNMT3A/3B, accompanied with changes in DNA methylation levels in the promoter regions of CHD-related genes. Folic acid supplement could decrease the occurrence of VSD in high homocysteine male mice. This study reveals that increased paternal homocysteine level increases VSD risk in the offspring, indicating that decreasing paternal homocysteine may be an intervening target of CHD.

What causes obesity in children and adolescents?

OBJECTIVE

To present the different aspects that may be involved in the genesis and maintenance of obesity in children and adolescents.

DATA SOURCE

Narrative review of articles published in the PubMed, Scielo, Lilacs, Scopus and Google Scholar databases, using the search terms: overweight, obesity, pre-conception, prenatal, infants, schoolchildren, children, and adolescents. The search was conducted in studies written in Portuguese, English and Spanish, including narrative, integrative or systematic reviews, meta-analyses, cross-sectional, case-control and cohort studies, published between 2003 and 2023.

DATA SYNTHESIS

A total of 598 studies were initially screened and 60 of them, which showed the main biopsychosocial aspects related to greater risks of excessive adiposity in the pediatric age, were included in the review. The data were presented taking into account the incidence of risk factors and their consequences in six periods: pre-conception, pre-natal, infant, preschool, school age, and adolescence.

CONCLUSIONS

The causal factors described in the scientific literature that have been shown to be related to obesity in childhood and adolescence are presented.

Pre- and Postnatal Exposures to Tobacco Smoking and Survival of Childhood Acute Lymphoblastic and Myeloid Leukemias in California, United States

BACKGROUND

Tobacco smoke adversely affects the prognosis of adult cancers including myeloid leukemia, but less is known in children.

METHODS

We evaluated whether pre- and postnatal exposures to tobacco smoke decrease 5-year survival of 1,235 childhood acute lymphoblastic leukemia (ALL) and 188 childhood acute myeloid leukemia (AML) cases derived from a population-based case-control study in California. Cases were diagnosed between 1995 and 2015 (median follow-up time of 13.2 years overall). We obtained data on tobacco smoking (before conception, during pregnancy, after birth), parental education and income, clinical features, and vital status through 2020. Cox proportional hazards regression was used to calculate hazard ratios (HR) and 95% confidence intervals (CI) for mortality associated with smoking, adjusting for sociodemographic characteristics and risk group (ALL only).

RESULTS

About 23% of mothers and 39% of fathers reported smoking and 130 children with ALL and 52 with AML died within 5 years. For AML, increased risks of death were observed among children whose fathers smoked before conception compared with nonsmoking fathers [HR = 1.41; 95% confidence interval (CI), 0.95-3.44 and 3.47; 95% CI, 1.37-8.81, respectively for <20 vs. ≥20 cigarettes per day; Ptrend = 0.01]. HR for child's passive smoking was 1.74, 95% CI, 0.81-3.73. Paternal preconception smoking may also reduce 5-year survival among ALL with favorable prognostic molecular subtypes (high hyperdiploidy and absence of IKZF1 gene deletion), although the associations did not reach statistical significance (Pheterogeneity = 0.07).

CONCLUSIONS

Paternal preconception smoking decreased 5-year survival of childhood AML.

IMPACT

Knowledge of exposure to tobacco smoking should be integrated in the treatment plan of childhood leukemias.

Parental adherence to healthy lifestyles in relation to the risk of obesity in offspring: A prospective cohort study in China

Background

While maternal adherence to a healthy lifestyle was shown to be associated with a lower risk of obesity in offspring, the potential role of overall parental lifestyles has not yet been explored. We aimed to address this gap by exploring whether parental adherence to an overall healthy lifestyle was associated with a lower risk of obesity in offspring.

Methods

We included 5881 children and adolescents aged 6-15 years at enrolment in the 2010, 2012, and 2014 waves of the China Family Panel Studies (CFPS) who were free of obesity and followed them until 2020. Parental healthy lifestyle score at study baseline was composed of five modifiable lifestyle factors (0-5; 1 for each): never smoking, non-habitual drinking, weekly exercise, modified dietary diversity score ≥5 points, and body mass index (BMI) of 18.5-23.9 kg/m2. We defined obesity according to the age- and gender-specific cutoffs by the BMI percentile curves for Chinese children aged 6-18 years. We used multivariable Cox proportional hazard models to examine the association between parental healthy lifestyle score (both as continuous and categorical variables) and risk of offspring obesity.

Results

Overall, 597 (10.2%) offspring developed obesity during a median follow-up of 6 years. Compared to the lowest tertile of parental healthy lifestyle score, participants in the highest tertile had a 42% (hazard ratio (HR) = 0.58; 95% confidence interval (CI) = 0.45-0.74) lower risk of obesity. Both maternal (HR = 0.75; 95% CI = 0.61-0.92) and paternal (HR = 0.73; 95% CI = 0.60-0.89) healthy lifestyle scores were associated with lower risks of obesity in offspring. For specific lifestyle factors, we observed beneficial associations for paternal diverse diet (HR = 0.73; 95% CI = 0.60-0.88) and healthy BMI (HR = 0.65; 95% CI = 0.55-0.78).

Conclusions

Adherence to an overall parental healthier lifestyle was associated with a lower risk of obesity in childhood and adolescence. This finding highlights the potential benefits of promoting a healthy lifestyle among parents for the primary prevention of offspring obesity.

Nicotine exposure of male mice protects offspring against carbon tetrachloride-induced acute liver injury

Paternal nicotine exposure can cause a phenotypic change in offspring. To study whether paternal nicotine exposure influences acute liver injury and repair of the offspring, we established a paternal nicotine exposure model in mice and treated the offspring mice with carbon tetrachloride (CCl₄ ) to induce acute liver injury. After the treatment of CCl₄ , the levels of alanine aminotransferase and aspartate aminotransferase in offspring serum of paternal nicotine exposed mice are about 37.44%, and 30.21% lower than the control mice, respectively. Transcription profiling screen and bioinformatics analysis of differently expressed genes in F1 mice liver revealed that the Wnt pathway was altered. The results demonstrate that nicotine exposure in male mice could enhance the activation of the Wnt pathway in F1 mice liver. The Wnt pathway facilitates cell proliferation and tissue repair. In conclusion, our findings showed that nicotine exposure of male mice protects hepatic against CCl₄ -induced acute injury in offspring by activating the Wnt pathway in the F1 liver.

Effects of paternal exposure to cigarette smoke on sperm DNA methylation and long-term metabolic syndrome in offspring

BACKGROUND

Although paternal exposure to cigarette smoke may contribute to obesity and metabolic syndrome in offspring, the underlying mechanisms remain uncertain.

METHODS

In the present study, we analyzed the sperm DNA-methylation profiles in tobacco-smoking normozoospermic (SN) men, non-tobacco-smoking normozoospermic (N) men, and non-smoking oligoasthenozoospermic (OA) men. Using a mouse model, we also analyzed global methylation and differentially methylated regions (DMRs) of the DLK1 gene in paternal spermatozoa and the livers of progeny. In addition, we quantified DLK1 expression, executed an intra-peritoneal glucose tolerance test (IPGTT), measured serum metabolites, and analyzed liver lipid accumulation in the F1 offspring.

RESULTS

Global sperm DNA-methylation levels were significantly elevated (p  < 0.05) in the SN group, and the methylation patterns were different among N, SN, and OA groups. Importantly, the methylation level of the DLK1 locus (cg11193865) was significantly elevated in the SN group compared to both N and OA groups (p  < 0.001). In the mouse model, the group exposed to cigarette smoke extract (CSE) exhibited a significantly higher global methylation DNA level in spermatozoa (p  < 0.001) and on the DMR sites of Dlk1 in 10-week-old male offspring (p  < 0.05), with a significant increase in Dlk1 expression in their livers (p  < 0.001). In addition, IPGTT and LDL levels were significantly altered (p  < 0.001), with elevated liver fat accumulation (p  < 0.05) in F1 offspring.

CONCLUSION

Paternal exposure to cigarette smoke led to increased global methylation of sperm DNA and alterations to the DMR of the DLK1 gene in the F1 generation, which may be inherited parentally and may perturb long-term metabolic function.

The Relationship Between Paternal Preconception Obesity and Health Behaviors and Childhood Obesity: Protocol for a Systematic Review

Background

Childhood obesity is a global public health concern and is a priority for researchers and policy makers. To overcome the epidemic of obesity, influencing factors throughout the life span need to be addressed, including those in the preconception period. A better understanding of the association between paternal preconception factors and childhood obesity is important for public health interventions.

Objective

This systematic review will examine the relationship between paternal preconception obesity and health behaviors and their offspring’s overweight or obesity.

Methods

Peer-reviewed quantitative studies and grey literature that report associations between paternal preconception obesity and health behaviors—such as smoking, exercise, and eating habits—and childhood overweight and obesity will be identified through a computerized literature search in 7 databases. The quality of each study will be assessed using the Quality Assessment Tool for Quantitative Studies. Characteristics of the included studies will be reported, and relevant findings from each paternal preconception exposure will be narratively synthesized. This review will follow the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) 2020 guidelines.

Results

This systematic review is anticipated to begin in December 2021 and be completed by the end of August 2022.

Conclusions

This systematic review will contribute to a better understanding of the relationship between preconception paternal exposures and their offspring’s overweight or obesity. Findings will help support health professionals working with prospective parents to educate fathers on the benefits of improving their weight and health behaviors during the preconception period.

International Registered Report Identifier (IRRID)

PRR1-10.2196/31254

Effect of Grandmaternal Smoking on Body Size and Proportions at Birth

Many long-term adverse effects of smoking during pregnancy are known. Increasingly, adverse effects in the grandchild after grandmaternal smoking during pregnancy are reported. We explored this in a birth cohort of 24,000 grandmother–mother–child triads identified from the Finnish Medical Birth Register in 1991–2016. Multiple logistic regression was used to analyze the association between any smoking during pregnancy by both grandmother and mother, or only grandmother or mother on adverse birth outcomes. No smoking by neither grandmother nor mother was used as the reference. As endpoints, preterm birth, low birth weight, small for gestational age (birth weight, birth length, head circumference), and body proportionality (low ponderal index, high brain-to-body ratio, high head-to-length ratio) were included. Smoking by both grandmother and mother was consistently associated with higher risks than smoking only by the mother. Birth length and weight were especially sensitive to (grand)maternal smoking. In conclusion, the combined effect of grandmaternal and maternal smoking is associated with higher risks than only maternal smoking.

Anything New about Paternal Contribution to Reproductive Outcomes? A Review of the Evidence

Paternal health and behavioral lifestyles affect reproductive and neonatal outcomes and yet the magnitude of these effects remain underestimated. Even though these impacts have been formally recognized as a central aspect of reproductive health, health care services in Europe often neglect the involvement of fathers in their reproductive programs. Following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines for systematic reviews, a literature search was carried out to assess the possible impact of paternal health on reproductive outcomes. The comprehensive strategy included cohort studies and meta-analysis available on PubMed, Web of Science, CINAHL, and Google scholar. Cross-referencing of bibliographies of the selected papers ensured wider study capture. Paternal factors were grouped into two categories respectively identified with the terms "Biological Paternal Factors" and "Lifestyle Paternal Factors". Advanced age may impair male fertility and affect early pregnancy stages. Increased body mass index, smoking, alcohol and recreational drugs, all alter seminal fluid parameters. Hazardous alcohol use correlates with low birthweight in pregnancy and harmful behavioral lifestyles have been linked to congenital heart defects, metabolic and neurodevelopmental disorders in the offspring. Measures targeting paternal health and lifestyle within the first 1,000 days' timeframe need to be implemented in couples undergoing reproductive decisions. Health professionals, as well as future fathers, must be aware of the benefits for the offspring associated with correct paternal behaviors. More research is needed to build guidelines and to implement specific programs aiming at reproductive health promotion.

Impact of Parental Exposure on Offspring Health in Humans

The possibility that parental life experiences and environmental exposures influence mental and physical health across generations is an important concept in biology and medicine. Evidence from animal models has established the existence of a non-genetic mode of inheritance. This form of heredity involves transmission of the effects of parental exposure to the offspring through epigenetic changes in the germline. Studying the mechanisms of epigenetic inheritance in humans is challenging because it is difficult to obtain multigeneration cohorts, to collect reproductive cells in exposed parents, and to exclude psychosocial and cultural confounders. Nonetheless, epidemiological studies in humans exposed to famine, stress/trauma, or toxicants have provided evidence that parental exposure can impact the health of descendants, in some cases, across several generations. A few studies have also started to reveal epigenetic changes in the periphery and sperm after certain exposures. This article reviews these studies and evaluates the current evidence for the potential contribution of epigenetic factors to heredity in humans. The challenges and limitations of this fundamental biological process, its implications, and its societal relevance are also discussed.

The 3G Multigenerational Cohort of Nova Scotian women and their mothers and offspring

BACKGROUND

The negative impact of exposures such as maternal obesity, excessive gestational weight gain, and hypertension in pregnancy on the health of the next generation has been well studied. Evidence from animal studies suggests that the effects of in utero exposures may persist into the second generation, but the epidemiological literature on the influence of pregnancy-related exposures across three generations in humans is sparse.

OBJECTIVES

This cohort was established to investigate associations between antenatal and perinatal exposures and health outcomes in women and their offspring.

POPULATION

The cohort includes women who were born and subsequently had their own pregnancies in the Canadian province of Nova Scotia from 1980 onward.

DESIGN

Intergenerational linkage of data in the Nova Scotia Atlee Perinatal Database was used to establish a population-based dynamic retrospective cohort.

METHODS

The cohort has prospectively collected information on sociodemographics, maternal health and health behaviours, pregnancy health and complications, and obstetrical and neonatal outcomes for two generations of women and their offspring.

PRELIMINARY RESULTS

As of October 2018, the 3G cohort included 14 978 grandmothers (born 1939-1986), 16 766 mothers or cohort women (born 1981-2003), and 28 638 children (born 1996-2018). The cohort women were generally younger than Nova Scotian women born after 1980, and as a result, characteristics associated with pregnancy at a younger age were more frequently seen in the cohort women; sampling weights will be created to account for this design effect. The cohort will be updated annually to capture future deliveries to women who are already in the cohort and women who become eligible for inclusion when they deliver their first child.

CONCLUSIONS

The 3G Multigenerational Cohort is a population-based cohort of women and their mothers and offspring, spanning a time period of 38 years, and provides the opportunity to study inter- and transgenerational associations across the maternal line.

Smoking and pregnancy: Epigenetics and developmental origins of the metabolic syndrome

Maternal smoking causes lower birth weight, birth defects, and other adverse pregnancy outcomes. Epidemiological evidence over the past four decades has grown stronger and the adverse outcomes attributed to maternal smoking and secondhand smoke exposure have expanded. This review presents findings of latent and persistent metabolic effects in offspring of smoking mothers like those observed in studies of maternal undernutrition during pregnancy. The phenotype of offspring of smoking mothers is like that associated with maternal undernutrition. Born smaller than offspring of nonsmokers, these children have increased risk of being overweight or obese later. Plausible mechanisms include in utero hypoxia, nicotine-induced reductions in uteroplacental blood flow, placental toxicity, or toxic growth restriction from the many toxicants in tobacco smoke. Studies have reported increased risk of insulin resistance, type 2 diabetes and hypertension although the evidence here is weaker than for overweight/obesity. Altered DNA methylation has been consistently documented in smoking mothers' offspring, and these epigenetic alterations are extensive and postnatally durable. A causal link between altered DNA methylation and the phenotypic changes observed in offspring remains to be firmly established, yet the association is strong, and mediation analyses suggest a causal link. Studies examining expression patterns of affected genes during childhood development and associated health outcomes should be instructive in this regard. The adverse effects of exposure to tobacco smoke during pregnancy now clearly include permanent metabolic derangements in offspring that can adversely affect life-long health.

Predictors of the dietary inflammatory index in children and associations with childhood weight status: A longitudinal analysis in the Lifeways Cross-Generation Cohort Study

BACKGROUND & AIMS

The family environment can influence offspring diet and weight status. Obesity is a pro-inflammatory state, which is associated with the dietary inflammatory index (DII®). Predictors of the DII in children (C-DII™) and its associations with childhood obesity are relatively unknown. We evaluated the intergenerational relationships between the energy-adjusted DII (E-DII) scores in adults, predictors of C-DII and associations with childhood weight status.

METHODS

The study comprises 551 children and index-child's mothers, fathers and grandparents in the Lifeways Cross-Generation Cohort Study. E-DII scores were generated at baseline for expectant mothers, fathers, and grandparents, and at 5-year follow-up for the mothers and children, using a validated food frequency questionnaire. Body mass index (BMI) and waist circumference were determined at age 5 and 9 years. Associations were assessed by logistic regression and mediation analysis.

RESULTS

Higher C-DII scores indicating a more pro-inflammatory diet among children, were associated with greater risk of childhood obesity at age 5 (OR:1.09; 95%CI:1.00-1.37; P = 0.02) and overweight/obese status at 5 and 9 years (OR:1.06; 95%CI:1.01-1.09; P = 0.01 and OR:1.12; 95%CI:1.07-1.18; P = 0.01, respectively). Maternal and paternal smoking during pregnancy (OR:1.98; 95%CI:1.19-3.03; P = 0.001 and OR:1.64; 95%CI:1.12-2.49; P = 0.006, respectively) increased likelihood of higher C-DII at age 5. Child BMI, TV watching and all meals given by the childcare provider were associated with a more pro-inflammatory diet (P < 0.05), whereas breastfeeding and family meals at home were associated with a more anti-inflammatory diet (P < 0.04). Higher maternal, but not paternal, E-DII scores during pregnancy (P < 0.001) and at 5-year follow-up (P = 0.008) were associated with more pro-inflammatory diet at age 5. Results from the mediation analysis suggest that maternal grandmothers E-DII scores may influence C-DII indirectly via the mothers E-DII scores.

CONCLUSIONS

A more pro-inflammatory dietary score was associated with childhood overweight and obesity. Parental, familial and personal factors independently influenced the C-DII score.

[Influence of pre-pregnancy parental body mass index, maternal weight gain during pregnancy, and their interaction on neonatal birth weight]

OBJECTIVE

To investigate the influence of pre-pregnancy parental body mass index (BMI), maternal weight gain during pregnancy, and their interaction on neonatal birth weight.

METHODS

A total of 1 127 pregnant women who underwent regular prenatal examinations and full-term singleton delivery in the First Hospital of Xi'an Jiaotong University from January 2017 to October 2018 were enrolled. The data on their pre-pregnancy BMI, maternal weight gain during pregnancy, pre-pregnancy BMI of the husband, and neonatal birth weight were collected. The interaction between pre-pregnancy parental BMI and maternal weight gain during pregnancy was analyzed, and their correlation with neonatal birth weight was analyzed.

RESULTS

Among the 1 127 full-term neonates, the detection rates of low birth weight neonates and macrosomia were 2.22% (25/1 127) and 3.82% (43/1 127) respectively. There were significant differences in pre-pregnancy parental BMI and maternal weight gain during pregnancy among the low birth weight, normal birth weight, and macrosomia groups (P<0.05). Neonatal birth weight was positively correlated with pre-pregnancy parental BMI and maternal weight gain during pregnancy (r=0.097-0.322, P<0.05). Low maternal weight before pregnancy increased the risk of low birth weight (RR=4.17, 95%CI: 1.86-9.38), and maternal overweight/obesity before pregnancy (RR=3.59, 95%CI: 1.93-6.67) and excessive weight gain during pregnancy (RR=3.21, 95%CI: 1.39-7.37) increased the risk of macrosomia. No interaction between pre-pregnancy maternal BMI and maternal weight gain during pregnancy was observed.

CONCLUSIONS

Pre-pregnancy parental BMI and maternal weight gain during pregnancy are related to neonatal birth weight, and there is no interaction between pre-pregnancy maternal BMI and maternal weight gain during pregnancy.

Maternal Dietary Glycemic and Insulinemic Indexes Are Not Associated with Birth Outcomes or Childhood Adiposity at 5 Years of Age in an Irish Cohort Study

BACKGROUND

High maternal dietary glycemic index (GI) and glycemic load (GL) may be associated with adverse offspring birth and postnatal adiposity outcomes through metabolic programming, but the evidence thus far, mainly from studies conducted in high-risk pregnant populations, has been inconclusive. No study has examined the influence of maternal insulin demand [measured by food insulinemic index (II) and insulinemic load (IL)] on offspring outcomes.

OBJECTIVES

We investigated associations between maternal GI, GL, II, and IL and offspring birth outcomes and postnatal adiposity in a general pregnant population.

METHODS

The study was based on data from 842 mother-child pairs from the Lifeways prospective cohort study in Ireland. Through the use of standard methodology, maternal GI, GL, II, and IL were derived from dietary information obtained via a validated food-frequency questionnaire in early pregnancy (12-16 wk). Birth outcomes were abstracted from hospital records. At 5-y follow-up, children's body mass index (BMI) and waist circumference were measured. Associations were assessed through the use of multivariable-adjusted regression analysis.

RESULTS

Mothers had a mean ± SD age of 30.3 ± 5.7 y and a mean BMI (kg/m2) of 23.9 ± 4.2. The mean ± SD for dietary glycemic and insulinemic indexes were: GI = 58.9 ± 4.4; GL = 152 ± 49; II = 57.4 ± 14.5; IL = 673 ± 267. After adjustment for confounders, no consistent associations were observed between maternal GI, GL, II, and IL and birth outcomes including birth weight, macrosomia, gestational age, and postterm births. Similarly, no association was observed with BMI and waist circumference z scores and childhood obesity (general and central) at 5-y follow-up. There was no evidence of a nonlinear relation between the studied indexes and outcomes.

CONCLUSIONS

We observed no clear relation between maternal GI, GL, II, and IL and offspring birth outcomes and childhood obesity in a general pregnant population.