Maternal smoking during pregnancy is associated with childhood bone fractures in offspring - A birth-cohort study of 6718 children

Fractures in Childhood and Young Adulthood According to Maternal Smoking in Late Pregnancy. A Danish Cohort Study

Fractures account for the most frequent cause of hospitalization during childhood and numbers have increased over time. Of all fractures in childhood and young adulthood, 66% are recurrent fractures, suggesting that some people are predestined for fractures. The aim of this study was to investigate the association between maternal smoking during late pregnancy and the risk of fractures in the children.The study included 11,082 mothers and their children from the cohort "Healthy Habits for Two" born between 1984 and 1987. Information about maternal smoking during pregnancy came from questionnaires filled out in pregnancy, while information about fractures was derived from the Danish National Patient Registry. Over a follow-up of 24 years (1994-2018), Cox regression with multiple failures was used to estimate hazard ratios (HRs) with 95% confidence intervals (CIs) for fractures in childhood and young adulthood according to maternal smoking in late pregnancy. Information about body mass index (BMI) and smoking status in young adulthood was included as time variant covariates.During an age span of 8-32 years, 6,420 fractures were observed. Of the mothers, 39.1% smoked during late pregnancy. Compared to children of mothers who did not smoke, children of mothers who smoked 1-9 cigarettes per day and 10+ cigarettes per day had an increased risk of fractures (HR 1.14 [CI: 1.06; 1.21] and HR 1.14 [CI: 1.07; 1.22], respectively). After adjusting for BMI and smoking status in young adulthood, the findings were slightly strengthened, showing an increased risk of fractures of 23 and 25% in children of mothers smoking 1-9 cigarettes per day and 10+ cigarettes per day, respectively.Maternal smoking during late pregnancy was associated with a higher risk of fractures in the child. This result indicates that exposure to cigarette smoke in utero may play a role in lifelong bone health.

Perturbations in Osteogenic Cell Fate Following Exposure to Constituents Present in Tobacco: A Combinatorial Study

Tobacco smoke contains between 7000 and 10,000 constituents, and only an evanescently low number of which have been identified, let alone been evaluated for their toxicity. Recently, the Food and Drug Administration has published a list of 93 chemical tobacco constituents that are harmful or potentially harmful to a number of cellular processes. However, their effect on developing skeletal cells is unknown. In this study, we used ToxPI, a computational tool, to prioritize constituents on this list for screening in osteogenically differentiating human embryonic stem cells and fibroblasts. In selected endpoint assays, we evaluated the potential of these chemicals to inhibit osteogenic differentiation success as well as their cytotoxicity. Six of these chemicals, which were ascribed an embryotoxic potential in our screen, as well as nicotine, which was not found to be osteotoxic in vitro, were then evaluated in combinatorial exposures, either in pairs of two or three. No one single chemical could be pinpointed as the culprit of reduced calcification in response to tobacco exposure. Combining chemicals at their half-maximal inhibitory concentration of differentiation often elicited expected decreases in calcification over the individual exposures; however, cytotoxicity was improved in many of the dual combinations. A reverse response was also noted, in which calcification output improved in combinatorial exposures. Results from ternary combinations reflected those from double combinations. Thus, the results from this study suggest that it may be difficult to isolate single chemicals as the primary drivers of skeletal embryotoxicity and that the full combination of chemicals in tobacco smoke may produce the hypomineralization phenotype that we have so far observed in vitro in human embryonic stem cells as well as in vivo in zebrafish.

Maternal Smoking During Pregnancy and Offspring's Risk for Bone Fracture in Childhood and Adolescence

Conditions during gestation, such as maternal smoking, may affect offspring's bone structure. This could increase the offspring's risk of bone fractures during childhood. In this study, we aimed to assess the association between prenatal exposure to maternal smoking and childhood bone fracture risk. We used a register-based birth cohort that included all children born in Finland between January 1987 and September 1990. After exclusions, the final study population consisted of 220,699 persons. Using a unique national identification number, we linked the cohort data to the fracture diagnosis in specialty care and covariate data using the Medical Birth Register (MBR), Statistics Finland and Care Register for Health Care (CRHC). The fractures were analyzed in three groups: all fractures, non-high-energy fractures, and high-energy fractures. The analyses were adjusted for sex, parity, child's year of birth, mother's age at childbirth, mother's and father's educational level, and mother's fracture status. We tested the association in three age groups: <1 year, 1-<5 years, and 5-<15 years using Cox and (recurrent fractures) Poisson regression. A total of 18,857 (8.5%) persons had at least one bone fracture diagnosis before the age of 15 years. In the age group 5-<15 years, maternal smoking during pregnancy was associated with higher fracture risk in all of the studied fracture groups: hazard ratio (HR) = 1.12 (95% confidence interval [CI] 1.06-1.17) in all fractures, 1.13 (95% CI 1.07-1.19) in non-high-energy, and 1.15 (95% CI 1.00-1.32) in high-energy fractures. There were no significant associations in other age groups in any of the fracture groups. No statistically significant association between maternal smoking during pregnancy and offspring's risk of recurrent fractures was found. In conclusion, 5- to 15-year-olds whose mothers have smoked during pregnancy have an increased risk of bone fractures treated in specialty care. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Sidestream Smoke Extracts from Harm-Reduction and Conventional Camel Cigarettes Inhibit Osteogenic Differentiation via Oxidative Stress and Differential Activation of intrinsic Apoptotic Pathways

Epidemiological studies suggest cigarette smoking as a probable environmental factor for a variety of congenital anomalies, including low bone mass, increased fracture risk and poor skeletal health. Human and animal in vitro models have confirmed hypomineralization of differentiating cell lines with sidestream smoke being more harmful to developing cells than mainstream smoke. Furthermore, first reports are emerging to suggest a differential impact of conventional versus harm-reduction tobacco products on bone tissue as it develops in the embryo or in vitro. To gather first insight into the molecular mechanism of such differences, we assessed the effect of sidestream smoke solutions from Camel (conventional) and Camel Blue (harm-reduction) cigarettes using a human embryonic stem cell osteogenic differentiation model. Sidestream smoke from the conventional Camel cigarettes concentration-dependently inhibited in vitro calcification triggered by high levels of mitochondrially generated oxidative stress, loss of mitochondrial membrane potential, and reduced ATP production. Camel sidestream smoke also induced DNA damage and caspase 9-dependent apoptosis. Camel Blue-exposed cells, in contrast, invoked only intermediate levels of reactive oxygen species insufficient to activate caspase 3/7. Despite the absence of apoptotic gene activation, damage to the mitochondrial phenotype was still noted concomitant with activation of an anti-inflammatory gene signature and inhibited mineralization. Collectively, the presented findings in differentiating pluripotent stem cells imply that embryos may exhibit low bone mineral density if exposed to environmental smoke during development.

Exposure to Cigarette Smoke Impedes Human Osteoblast Differentiation Independently of Nicotine

INTRODUCTION

Tobacco smoking has been implicated in an array of adverse health outcomes, including those that affect adult bone. However, little is known about the impact of tobacco products on developing bone tissue as it develops in the embryo.

AIMS AND METHODS

Here, human embryonic stem cells were differentiated into osteoblasts in vitro and concomitantly exposed to various concentrations of smoke solutions from two conventional, one additive-free and two harm-reduction brands of cigarettes. Differentiation inhibition was determined by calcium assays that quantified matrix mineralization and compared to the cytotoxicity of the tobacco product.

RESULTS

Exposure to mainstream smoke from conventional and additive-free cigarettes caused no inhibition of cell viability or mineralization, while sidestream smoke (SS) concentration-dependently produced cell death. In contrast, mineralization was inhibited only by the highest mainstream concentration of harm-reduction smoke solution. Additionally, sidestream smoke solution from the harm-reduction cigarettes impeded calcification at concentrations lower than those determined to be cytotoxic for conventional products.

CONCLUSIONS

Sidestream smoke impaired in vitro osteogenesis at subtoxic concentrations. In addition, though often perceived as safer, smoke from harm-reduction cigarettes was more potent in inhibiting in vitro osteogenesis than smoke from conventional cigarettes.

IMPLICATIONS

This study adds to a growing list of adverse outcomes associated with pre-natal tobacco exposure. Specifically, in vitro exposure to tobacco products interfered with osteogenic differentiation of human embryonic stem cells, a well-established surrogate model for human embryonic bone development. Contrasting a diverse array of tobacco products unveiled that sidestream smoke was generally more developmentally osteotoxic than mainstream smoke and that harm-reduction products may not be less harmful than conventional products, adverse effects that were seemingly independent of nicotine.

Maternal vitamin D and offspring fracture risk: the Vitamin D in Pregnancy study

Vitamin D is important for bone health and strength. Previous studies report 25-hydroxyvitamin D (25(OH)D) exposure during pregnancy may impact offspring bone health later in life. In this study, maternal 25(OH)D at recruitment was associated with a lower fracture risk in boys and an increased fracture risk in girls at 28-32 weeks gestation.

PURPOSE

Maternal 25-hydroxyvitamin D (25(OH)D) in pregnancy has been shown to be associated with offspring bone measures in some studies, but few have examined fracture risk. We aimed to determine associations between maternal vitamin D status and offspring fracture risk.

METHODS

In total, 475 mother-child pairs participating in the Vitamin D in Pregnancy study in southeastern Australia were recruited. Maternal serum samples were taken at recruitment (< 16 weeks gestation) and/or 28-32 weeks gestation and analysed for 25(OH)D. Incident fractures in children were ascertained from date of birth (2002-2004) until December 31, 2012. Cox proportional hazard models included maternal age at recruitment, offspring sex, birth weight, gestation length and season of vitamin D sample.

RESULTS

Complete follow-up data were available for 400 children (median age = 9.5 years). There were 68 (17.0%) children who sustained at least one fracture. Higher maternal 25(OH)D (per 10 nmol/L) in early gestation was weakly associated with a decreased fracture risk in boys (HR 0.82; 95% CI 0.68, 0.99; p = 0.048) but not girls (HR 1.10; 95% CI 0.98, 1.25; p = 0.11). At late gestation, higher maternal 25(OH)D was associated with increased fracture risk in girls (HR 1.11; 95% CI 1.01, 1.23; p = 0.038) but not boys (HR 0.94; 95% CI 0.80, 1.10; p = 0.42). No statistically significant relationships were detected in analyses investigating 25(OH)D as a categorical variable.

CONCLUSION

There is some evidence that higher maternal 25(OH)D at recruitment was associated with lower fracture risk in boys, while higher maternal 25(OH)D at 28-32 weeks gestation was associated with an increased fracture risk in girls.

Correlation Between Maternal Smoking During Pregnancy and Dental Caries in Children: A Systematic Review and Meta-Analysis

Background: Dental caries is a long-standing oral health problem for children all over the world. The available evidence shows that the association between maternal smoking during pregnancy and childhood caries is still controversial. Therefore, the aim of this systematic review and meta-analysis was to determine whether there was a correlation of prenatal smoking and dental caries in children.

Methods: PubMed, EMBASE, Cochrane, Web of Science, and Scopus databases were searched for observational studies assessing the relationship between maternal smoking during the pregnancy and childhood caries. According to the predesigned eligibility criteria and items, studies selection, and data extraction were conducted, respectively. The effect estimates were pooled using a fixed-effect model or a random-effect model. Newcastle-Ottawa Scale (NOS) was adopted to evaluate the methodological quality of the included studies. All analyses were carried out through Stata 12.0 software.

Results: Our systematic review included a total of 11 studies, of which 6 cross-sectional studies and 3 longitudinal studies were included in the final meta-analysis. The pooled estimates indicated maternal smoking during pregnancy was significantly associated with dental caries in children both in cross-sectional studies (OR = 1.57, 95% CI = 1.47–1.67) and longitudinal studies (RR = 1.26, 95% CI = 1.07–1.48). Sensitivity analyses confirmed the overall effect estimates were robust.

Conclusions: There is a significant correlation of maternal smoking during pregnancy and childhood caries. However, the causal relationship between them cannot be determined. More prospective and extensive studies on this theme is needed for verification. Even so, it is necessary for pregnant women and women of reproductive age to quit smoking. Strategies must be developed to raise public awareness about the impact of prenatal smoking on children's oral health.

Association between maternal smoking during pregnancy and risk of bone fractures in offspring: a systematic review and meta-analysis

This study aimed to investigate the effect of maternal smoking during pregnancy (MSDP) on the risk of bone fractures in the offspring through a systematic review and meta-analysis. The PubMed, Web of Science, and Scopus databases were systematically searched for relevant articles published through July 2019. According to heterogeneity, the pooled risk ratio (RR) and odds ratio (OR) and their corresponding 95% confidence interval (CI) were obtained using fixed or random effects models. The heterogeneity and quality of the included studies were assessed by the I-squared (I2 ) statistic and the Newcastle-Ottawa scale, respectively. Sensitivity analyses were performed to test the effect of MSDP misclassification on the results. The review of 842 search records yielded 5 studies including 8,746 mother-child pairs that were included in the meta-analysis. Pooling adjusted effect measures showed that MSDP was not associated with a later risk of bone fractures in the offspring (pooled RR, 1.15; 95% CI, 0.84-1.58; I2 =66.8%; P=0.049). After the adjustment for misclassification, MSDP may be associated with a 27% increased risk of bone fracture (pooled OR, 1.27; 95% CI, 1.00-1.62; I2 =0%; P=0.537). After the adjustment for misclassification, MSDP is associated with an increased risk of bone fractures among children whose mothers smoked during pregnancy.

Nutrients, Diet, and Other Factors in Prenatal Life and Bone Health in Young Adults: A Systematic Review of Longitudinal Studies

Optimizing skeletal health in early life has potential effects on bone health later in childhood and in adulthood. We aimed to evaluate the existing evidence that maternal exposures during pregnancy have an impact on the subsequent bone health among offspring in young adults aged between 16 and 30 years. The protocol is registered in the International Prospective Register of Systematic Reviews (PROSPERO) (ID: CRD42019126890). The search was conducted up to 2 April 2019. We included seven observational prospective cohort studies that examined the association between maternal dietary factors, vitamin D concentration, age, preeclampsia, and smoking with any bone indices among offspring. The results indicated that high concentrations of maternal vitamin D; low fat intake; and high intakes of calcium, phosphorus, and magnesium may increase the bone mineral density in offspring at age 16. Evidence also suggests that the offspring of younger mothers may have a higher peak bone mass. It remains inconclusive whether there is an influence of preeclampsia or maternal smoking on bone health among young adults. Our assessment of internal validity warrants a cautious interpretation of these results, as all of the included studies were judged to have serious risks of bias. High-quality studies assessing whether prenatal prognostic factors are associated with bone health in young adults are needed.

Maternal alcohol consumption during pregnancy associates with bone fractures in early childhood. A birth-cohort study of 6718 participants

Fractures are common injuries in children, but their underlying biological and environmental risk factors are not well known. Maternal alcohol consumption during pregnancy is a known risk factor for bone malformations and impaired growth, in connection with Fetal Alcohol Spectrum Disorders (FASD). There is evidence that even lower doses of alcohol than what is needed for FASD can cause changes in the developing bone. Birth weight and length may also associate to childhood fractures. The aim of this study was to find out whether there exist associations between maternal alcohol use during pregnancy, birth weight or length and fractures of the long bones in childhood. A prospective birth cohort was performed, including all women in Northern Finland with an expected date of delivery between July 1985 and June 1986, and their offspring (N = 9432). The National Hospital Discharge Register (NHDR) provided the information on inpatient treated fractures. The subjects who declined participation or were treated as outpatient were excluded. The final study population consisted of 6718 children (71.2%). 98 (1.5%) of them suffered from inpatient treated fracture of a long bone (N = 105). Maternal alcohol consumption during pregnancy was inquired by questionnaires during late pregnancy or shortly after parturition. The birth length and weight were recorded immediately after birth. Binomial regression analysis was used to determine the association between the potential explanatory variables and bone fractures. Gender, socioeconomic status of the family, maternal age, premature birth, body mass index (BMI) of the children and maternal smoking during pregnancy were taken as possible confounders. In this study, the maternal alcohol consumption during pregnancy was associated to 2.22-fold (CI 1.09-4.12, p < 0.02) increased risk of a long bone fracture before the age of eight. Birth weight or length did not associate to childhood fractures. Bone fractures are an important cause of morbidity in childhood. Their prevention should start from the prenatal period by protecting the fetus from the alcohol exposure.

A single genetic locus associated with pediatric fractures: A genome-wide association study on 3,230 patients

The understanding of the biological and environmental risk factors of fractures in pediatrics is limited. Previous studies have reported that fractures involve heritable traits, but the genetic factors contributing to the risk of fractures remain elusive. Furthermore, genetic influences specific to immature bone have not been thoroughly studied. Therefore, the aim of the present study was to identify genetic variations that are associated with fractures in early childhood. The present study used a prospective Northern Finland Birth Cohort (year 1986; n=9,432). The study population was comprised of 3,230 cohort members with available genotype data. A total of 48 members of the cohort (1.5%) had in-hospital treated bone fractures during their first 6 years of life. Furthermore, individuals without fracture (n=3,182) were used as controls. A genome-wide association study (GWAS) was performed using a frequentist association test. In the GWAS analysis, a linear regression model was fitted to test for additive effects of single-nucleotide polymorphisms (SNPs; genotype dosage) adjusting for sex and performing population stratification using genotypic principal components. Using the GWAS analysis, the present study identified one locus with a significant association with fractures during childhood on chromosome 10 (rs112635931) and six loci with a suggested implication. The lead SNP rs112635931 was located near proline- and serine-rich 2 (PROSER2) antisense RNA 1 (PROSER2-AS1) and PROSER2, thus suggesting that these may be novel candidate genes associated with the risk of pediatric fractures.

Association between maternal smoking and child bone mineral density: a systematic review and meta-analysis

Maternal smoking during pregnancy has detrimental effects on fetal development. The current review examined the differences in offspring's bone mineral density (BMD) between mothers smoked during pregnancy and those who did not. A systematic review and meta-analysis on the studies investigating the influence of maternal smoking during pregnancy on children or neonates' bone measures published up to October 30, 2018, was performed. BMD results measured at different body sites were pooled and then fixed or random effect models were used based on the presence of heterogeneity. The desired pooled effect size was the offspring's BMD mean difference with 95% confidence interval between smoker and non-smoker mothers. Sensitivity analysis was performed for birth weight and current weight, two important mediator/confounders causing heterogeneity. Overall, eight studies consisting of 17,931 participants aged from infancy to 18 years were included. According to the fixed effect model, the mean of BMD in offspring whose mothers smoked during pregnancy was 0.01 g/cm² lower than those with non-smoker mothers (95% CI = - 0.02 to - 0.002). However, subgroup meta-analysis adjusted for birth weight and current weight demonstrated no significant mean difference between BMD of children with smoker and non-smoker mothers (d = 0.06, 95% CI = -0.04 to 0.16, p value = 0.25 and d = - 0.005, 95% CI = - 0.01 to 0.004, p value = 0.28, respectively). According to available studies, it is suggested that maternal smoking during pregnancy does not have direct effect on the offspring's BMD. Instead, this association might be confounded by other factors such as placental weight, birth weight, and current body size of children.

Maternal smoking during pregnancy and fractures in offspring: national register based sibling comparison study

OBJECTIVE

To study the impact of maternal smoking during pregnancy on fractures in offspring during different developmental stages of life.

DESIGN

National register based birth cohort study with a sibling comparison design.

SETTING

Sweden.

PARTICIPANTS

1 680 307 people born in Sweden between 1983 and 2000 to women who smoked (n=377 367, 22.5%) and did not smoke (n=1 302 940) in early pregnancy. Follow-up was until 31 December 2014.

MAIN OUTCOME MEASURE

Fractures by attained age up to 32 years.

RESULTS

During a median follow-up of 21.1 years, 377 970 fractures were observed (the overall incidence rate for fracture standardised by calendar year of birth was 11.8 per 1000 person years). The association between maternal smoking during pregnancy and risk of fracture in offspring differed by attained age. Maternal smoking was associated with a higher rate of fractures in offspring before 1 year of age in the entire cohort (birth year standardised fracture rates in those exposed and unexposed to maternal smoking were 1.59 and 1.28 per 1000 person years, respectively). After adjustment for potential confounders the hazard ratio for maternal smoking compared with no smoking was 1.27 (95% confidence interval 1.12 to 1.45). This association followed a dose dependent pattern (compared with no smoking, hazard ratios for 1-9 cigarettes/day and ≥10 cigarettes/day were 1.20 (95% confidence interval 1.03 to 1.39) and 1.41 (1.18 to 1.69), respectively) and persisted in within-sibship comparisons although with wider confidence intervals (compared with no smoking, 1.58 (1.01 to 2.46)). Maternal smoking during pregnancy was also associated with an increased fracture incidence in offspring from age 5 to 32 years in whole cohort analyses, but these associations did not follow a dose dependent gradient. In within-sibship analyses, which controls for confounding by measured and unmeasured shared familial factors, corresponding point estimates were all close to null. Maternal smoking was not associated with risk of fracture in offspring between the ages of 1 and 5 years in any of the models.

CONCLUSION

Prenatal exposure to maternal smoking is associated with an increased rate of fracture during the first year of life but does not seem to have a long lasting biological influence on fractures later in childhood and up to early adulthood.

Recent trends in children's elbow dislocation with or without a concomitant fracture

BACKGROUND

The elbow is the joint that most usually dislocates in children. In contrast to the widely known recent increase in the incidence of upper-extremity fractures and their operative treatment in children, potential trends in elbow dislocation are not clear. In this study we aimed to clarify the recent epidemiology of childhood elbow dislocation, in particular the potential change in incidence and treatment.

METHODS

A population-based study was performed to evaluate the annual incidence and the characteristics of injury, patients and treatment. All children < 16 years of age with an elbow dislocation in 1996-2014 in the Oulu University Hospital District, Finland, were included. Elbow dislocations with and without an associated fracture were included. The mean number of children in the population at risk was 85,600, according Statistics Finland.

RESULTS

There were 104 patients with a mean age of 11.3 years (SD 2.6). The annual incidence was 6.4 (mean) per 100,000 children in 1996-2014 and no changing trend in incidence during the study period was found. Trampoline jumping was the most usual reason for the dislocations (N = 15, 14.4%). The majority (N = 73/104, 70.2%) were treated non-operatively by reduction and casting. There was no change in surgical treatment during the study time.

CONCLUSION

In contrast to increasing incidence of upper-extremity fractures in children, there has not been a change in the incidence of elbow dislocation in children. There was no change in surgical treatment in 1996-2014.

Prenatal influences on bone health in children

INTRODUCTION

Optimising bone health might reduce the burden of both fractures in childhood and fragility fractures in later life. A number of maternal dietary and non-dietary factors have been identified that might influence offspring bone health and represent targets for intervention.

AREAS COVERED

This article will outline the accrual of bone mineral throughout the life course and how observational and intervention studies have shown that maternal diet, in particular maternal calcium and 25-hydroxyvitamin D [25(OH)D] status, and lifestyle are associated with offspring bone mineralization. Studies examining the effects of maternal micronutrient supplementation on offspring bone mineral density (BMD) will also be discussed.

EXPERT COMMENTARY

There is a wealth of observational evidence relating maternal diet to offspring BMD. However, high quality randomized controlled trials, such as the ongoing MAVIDOS study, are needed before these findings can be definitively translated into public health advice.

Video-based kinetic analysis of calcification in live osteogenic human embryonic stem cell cultures reveals the developmentally toxic effect of Snus tobacco extract

Epidemiological studies suggest tobacco consumption as a probable environmental factor for a variety of congenital anomalies, including low bone mass and increased fracture risk. Despite intensive public health initiatives to publicize the detrimental effects of tobacco use during pregnancy, approximately 10-20% of women in the United States still consume tobacco during pregnancy, some opting for so-called harm-reduction tobacco. These include Snus, a type of orally-consumed yet spit-free chewing tobacco, which is purported to expose users to fewer harmful chemicals. Concerns remain from a developmental health perspective since Snus has not reduced overall health risk to consumers and virtually nothing is known about whether skeletal problems from intrauterine exposure arise in the embryo. Utilizing a newly developed video-based calcification assay we determined that extracts from Snus tobacco hindered calcification of osteoblasts derived from pluripotent stem cells early on in their differentiation. Nicotine, a major component of tobacco products, had no measurable effect in the tested concentration range. However, through the extraction of video data, we determined that the tobacco-specific nitrosamine N'-nitrosonornicotine caused a reduction in calcification with similar kinetics as the complete Snus extract. From measurements of actual nitrosamine concentrations in Snus tobacco extract we furthermore conclude that N'-nitrosonornicotine has the potential to be a major trigger of developmental osteotoxicity caused by Snus tobacco.

A novel variant of osteogenesis imperfecta type IV and low serum phosphorus level caused by a Val94Asp mutation in COL1A1

Osteogenesis imperfecta (OI) is a rare congenital disorder characterized by bone fragility and fractures, and associated with bone deformity, short stature, dentin, ligament and blue-gray eye sclera. OI is caused by a heterozygous mutation in collagen α-1(I) chain (COL1A1) or collagen α-2(I) chain (COL1A2) genes that encode α chains of type I collagen. Collagen α chain peptide contains an N-propeptide, which has a role in assembly and processing of collagen. Point mutations in the N-propeptide domain appear to trigger OI. In the present study, a novel heterozygous missense mutation, c.281T>A (p.Val94Asp), was identified in the von Willebrand C domain of N-terminal of type I collagen in an individual with type IV OI. The majority of N-terminal mutations are associated with OI/Ehlers-Danlos syndrome (EDS); however, in the present study, the affected individual did not suffer from EDS and the level of serum phosphorus of the patient was low (0.67 mmol/l). A number of clinical phenotypes were observed at the same variation site or in the same region on the polypeptide chain of COL1A, which suggests that additional genetic and environmental factors may influence the severity of OI. The present study may provide insight into the phenotype-genotype association in collagen-associated diseases and improve clinical diagnosis of OI.

Association between prenatal maternal cigarette smoking and early childhood caries. A systematic review

Background

The aim of the present study was to assess the relationship between prenatal maternal cigarette smoking (PMCS) and early childhood caries (ECC) through a systematic review of currently available scientific evidence.

Material and Methods

To address the focused question: “Is there an association between PMCS and ECC?” an electronic literature search without time or language restrictions was conducted till May 2017 in indexed databases using various key words including dental caries, pregnancy, smoking, tobacco products and child. Letters to the editor, commentaries, reviews, case reports and case series and studies in which, ECC was investigated without clinical dental examination, were excluded.

Results

Eight observational cross-sectional studies were included. The number of participants ranged between 1102 and 76920 children with age ranging between 24 months and 72 months. Seven studies reported a positive association between PMCS and ECC. One study reported that children whose mother smoked at least five cigarettes/day during pregnancy presented a higher caries severity level compared with to those whose mothers did not smoke. One study showed no association between ECC and PMCS.

Conclusions

The association between PMCS and ECC remains debatable. Further well-designed longitudinal studies are needed in this regard.

Key words:Cigarette, early childhood caries, pregnancy, risk factors, smoking.