Effect of smoking on maternal glucose metabolism

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.

Smoking during pregnancy and risk of abnormal glucose tolerance: a prospective cohort study

BACKGROUND

Disturbances in glucose metabolism during pregnancy are associated with negative sequalae for both mother and infant. The association between smoking and abnormal glucose tolerance (AGT) remains controversial. Therefore, the aim of this study was to examine the relationship between smoking prior to and during pregnancy and risk of AGT.

METHODS

We utilized data from a prospective cohort of 1,006 Hispanic (predominantly Puerto Rican) prenatal care patients in Western Massachusetts. Women reported pre- and early pregnancy smoking at recruitment (mean = 15 weeks) and mid pregnancy smoking at a second interview (mean = 28 weeks). AGT was defined as > 135 mg/dL on the routine 1-hour glucose tolerance test (1-hr OGTT). We used multivariable regression to assess the effect of pre, early, and mid-pregnancy smoking on risk of AGT and screening plasma glucose value from the 1-hr OGTT.

RESULTS

In age-adjusted models, women who smoked > 0-9 cigarettes/day in pre-pregnancy had an increased risk of AGT (OR = 1.90; 95% CI 1.02-3.55) compared to non-smokers; this was attenuated in multivariable models. Smoking in early (OR = 0.48; 95% CI 0.21-1.10) and mid pregnancy (OR = 0.38; 95% CI 0.13-1.11) were not associated with AGT in multivariable models. Smoking during early and mid pregnancy were independently associated with lower glucose screening values, while smoking in pre-pregnancy was not.

CONCLUSIONS

In this prospective cohort of Hispanic women, we did not observe an association between smoking prior to or during pregnancy and risk of AGT. Findings from this study, although based on small numbers of cases, extend prior research to the Hispanic population.

Cigarette smoking and risk of gestational diabetes: a systematic review of observational studies

BACKGROUND

Gestational diabetes is a prevalent disease associated with adverse outcomes of pregnancy. Smoking as been associated with glucose intolerance during pregnancy in some but not all studies. Therefore, we aimed to systematically review all epidemiological evidence to examine the association between cigarette smoking during pregnancy and risk of developing gestational diabetes mellitus.

METHODS

We conducted a systematic review of articles published up to 2007, using PubMed, Embase, LILACS e CINAHL to identify the articles. Because this review focuses on studies of smoking during pregnancy, we excluded studies evaluating smoking outside pregnancy. Two investigators independently abstracted information on participant's characteristics, assessment of exposure and outcome, and estimates for the association under study. We evaluated the studies for publication bias and performed heterogeneity analyses. We also assessed the effect of each study individually through sensitivity analysis.

RESULTS

We found and critically reviewed 32 studies, of which 12 met the criteria for inclusion in the review. Most of the studies provided only unadjusted measurements. Combining the results of the individual studies, we obtained a crude odds ratio of 1.03 (99% CI 0.85-1.25). Only 4 studies presented adjusted measurements of association, and no association was found when these alone were analyzed (OR 0.95; 99% CI 0.85-1.07). Subgroup analysis could not be done due to small sample size.

CONCLUSION

The number of studies is small, with major heterogeneity in research design and findings. Taken together, current data do not support an association between cigarette smoking during pregnancy and the risk of gestational diabetes.

The effects of smoking in pregnancy on factors influencing fetal growth

AIM

To evaluate the influence of maternal smoking during pregnancy on factors influencing fetal growth.

METHODS

Thirty newborns of smoking mothers were prospectively compared with 60 newborns of non-smoking mothers. Pre-albumin, albumin, triglycerides, glucose, insulin, insulin-like growth factor I, IGF binding protein 3, pH, lactic acid, erythropoietin and hemoglobin concentrations were measured in umbilical cord blood.

RESULTS

Infants of smoking mothers had a significantly lower birth weight (3418 +/- 533 vs. 3863 +/- 503 g; p < 0.001), length (50.5 +/- 2,6 vs. 52.3 +/- 1.9 cm; p < 0.001) and head circumference (34.6 +/- 1.8 vs. 35.8 +/- 1.1 cm; p < 0.001) than controls. They also had significantly lower insulin (3.2 (2.0-4.9) vs. 5.8 (4.6-7.1) mU/L; p = 0.008), insulin-like growth factor I (54.4 +/- 32.5 vs. 93.8 +/- 54.5 microg/L; p = 0.001) and IGF binding protein 3 (1664 +/- 432 vs. 1943 +/- 421 microg/L; p = 0.01) concentrations, than controls. Infants of smoking mothers also had significantly higher hemoglobin (167 +/- 14 vs. 157 +/- 13 g/L; p = 0.002) and erythropoietin (42.3 (25.1-72.4) vs. 26.3 (21.9-30.9) U/L; p = 0.03) than controls, but not pH or lactate concentrations. There was no significant difference in pre-albumin, albumin, triglycerides and glucose concentrations.

CONCLUSIONS

Smoking during pregnancy causes symmetrical fetal growth impairment, possibly due to decreased oxygen transport to the fetus and decreased concentrations of fetal insulin, insulin-like growth factor I and IGF binding protein 3.

Glucose tolerance and risk of gestational diabetes mellitus in nulliparous women who smoke during pregnancy

Gestational diabetes mellitus has been associated with adverse maternal and infant outcomes, including preeclampsia and fetal macrosomia. Although cigarette smoking has been associated with increased insulin resistance, its effect on gestational diabetes mellitus risk is uncertain. The authors evaluated the effects of smoking on glucose tolerance in a cohort of pregnant women who participated in the Calcium for Preeclampsia Prevention trial, a randomized study of nulliparous women conducted in five US medical centers from 1992 to 1995. Results of screening and diagnostic testing for gestational diabetes mellitus were analyzed. For 3,774 of the 4,589 women enrolled, plasma glucose concentration 1 hour after a 50-g oral glucose challenge and complete information on pregnancy outcome were available; for 3,602 of the women, gestational diabetes mellitus status was known. Adjusted mean 1-hour plasma glucose concentration (mg/dl) was elevated in women who smoked at study enrollment (112.6, 95% confidence interval: 110.0, 115.3) compared with women who had never smoked (108.3, 95% confidence interval: 106.7, 109.8; p < 0.01). Women who smoked were at increased risk of gestational diabetes mellitus when criteria proposed by the National Diabetes Data Group were used (adjusted odds ratio = 1.9, 95% confidence interval: 1.0, 3.6). These findings support an association between smoking and gestational diabetes mellitus.

Perinatal bone turnover in term human neonates and the influence of maternal smoking

Bone turnover in neonates appears independently of the comparably low maternal bone turnover, but there is only sparse information on the effect of the in utero environment on fetal bone turnover. Postnatally, the resuming growth velocity and alterations in mineral homeostasis affect neonatal bone turnover. This study evaluated the relationship of bone marker concentrations to maternal and fetal auxological variables as well as maternal smoking and assessed the short-term change in bone markers during the first days of life. Serum markers of bone formation [osteocalcin and bone-specific alkaline phosphatase (BALP)] and bone resorption (C-terminal telopeptide of type I collagen) were measured in cord blood and at discharge (median d 3) in 69 healthy term neonates. Concentrations of BALP were significantly lower in neonates of smokers (n = 16) compared with nonsmokers (n = 53), both at birth (p = 0.013) and at discharge (p = 0.036). Both cord osteocalcin and BALP were negatively related to maternal weight and maternal body mass index. Maternal smoking and pregnancy weight gain were the predictors of cord BALP (r2 = 0.24; p < 0.001), whereas the mode of delivery best predicted cord C-terminal telopeptide of type I collagen levels (r2 = 0.19; p < 0.001). C-terminal telopeptide of type I collagen and osteocalcin increased significantly (p < 0.001) from birth to discharge, whereas BALP levels did not change significantly during the same period. Our results suggest that maternal smoking during pregnancy and maternal obesity may have a negative impact on fetal bone formation. The significant increase of osteocalcin and C-terminal telopeptide of type I collagen may result either from an increase in bone turnover or altered renal clearance.

The effect of smoking on glucose homeostasis and fetal growth in pregnant women

OBJECTIVE

To examine the relationship between maternal blood glucose levels, cigarette smoking in pregnancy and fetal growth.

DESIGN

A prospective study of healthy parous women from early pregnancy and their infants.

SETTING

Three Scandinavian university hospitals covering all deliveries from well defined geographical areas.

SUBJECTS

Study groups of non-smoking (150), light smoking (131) and heavily smoking mothers (218), para 1 and 2 and with > 37 weeks of gestational length.

MAIN OUTCOME MEASURES

Oral glucose tolerance test performed in pregnancy week 37, glycated hemoglobin measured the 3rd day post partum and neonatal anthropometric parameters including skinfold measurements.

RESULTS

Among heavily smoking mothers 12.4% displayed a 2-hour glucose value in the range of gestational diabetes (> 8.5 mmol/l) compared to 9.2% among light smokers and 6.0% among nonsmokers (p < 0.05). Heavily smoking mothers also had significantly (p < 0.05) higher glycated hemoglobin compared to nonsmokers, 5.01 v.s. 4.86. These changes in glucose parameters in smokers were not associated with higher birthweights.

CONCLUSIONS

Smoking in pregnancy affects parameters of glucose homeostasis in the direction of gestational diabetes. The retarding effect of smoking on fetal growth abolished any expected growth stimulation from the higher blood glucose levels seen in the smokers.

Maternal smoking during pregnancy, growth, and bone mass in prepubertal children

There have been no studies of smoking during pregnancy and bone mineralization in children. The objective of this population-based longitudinal study was to determine whether maternal smoking during pregnancy is associated with bone mass and other growth variables in prepubertal children. We studied 330 8-year-old male and female children representing 47% of those who originally took part in a study of risk factors for Sudden Infant Death Syndrome in 1988. The main outcome measures were bone mineral density measured by a Hologic QDR2000 densitometer: birth weight, placental weight, height, and weight. Maternal smoking during pregnancy was associated with deficits in growth with these children having lower height (-1.53 cm, 95% confidence interval [CI] -3.03 to -0.03) and a trend to lower weight (-1.35 kg, 95% CI -2.75 to 0.11) at age 8. Furthermore, there was a disproportionate deficit in bone mass such that those children whose mothers smoked during pregnancy had lower size adjusted bone mass at the lumbar spine (-0.019 g/cm2, 95% CI -0.033 to -0.005) and femoral neck (-0.018 g/cm2, 95%CI -0.034 to -0.002) but not total body (-0.005 g/cm2, 95% CI -0.015 to 0.005). This association was only present for children born at term. Mothers who smoked during pregnancy also had lower placental weight (- 56 g, 95% CI -95 to -17), and further adjustment for placental weight led to nonsignificant results for smoking with both growth and bone parameters, suggesting that these associations may be mediated through placental size and function. Maternal smoking habit in 1996 was not significantly associated with bone mass at any site. In conclusion, this study has demonstrated a long-term negative association between maternal smoking during pregnancy and both growth and bone mass in children born at term, and suggests that the timing of exposure rather than the dose or duration is critical. If these associations are present in other populations and they persist until the attainment of peak bone mass, then our findings suggest that osteoporosis prevention programs should start very early in the life cycle.

Maternal smoking and body composition of the newborn

The influence on neonatal anthropometry of maternal cigarette smoking in pregnancy was investigated in 933 parous women. Anthropometric growth parameters including skinfold measurements were studied in the newborns. After adjustment for maternal age, pre-pregnancy weight, height and pregnancy weight gain, smoking had a clear dose-dependent negative effect on all anthropometric characteristics in the infant. In contrast to the results obtained in other investigations, the reduced birth weight of the infants of smoking mothers was not found to be primarily due to a reduction in lean body mass; nor was fat deposition found to be reduced. Fetal anthropometry was also negatively affected in infants born to mothers who stopped smoking during pregnancy.

Cigarette smoking and urinary incontinence in women--a new calculative method of estimating the exposure to smoke

The aim of the study was to investigate the relation between cigarette smoking and urinary incontinence. A group of 80 women with incontinence (Group A) were tested urodynamically and compared with a group of 80 continent women (Group B). Patients were divided into smokers (S) and non-smokers (NS) with the incontinent ones classified as suffering from stress (SI) or motor in-continent (UI). The assessment of the smoking behavior of each individual focused upon the tar and nicotine content of each cigarette. The overall exposure to smoke was assessed as follows: tar/nicotine content in mg per cigarette x consumed cigarettes per day x duration of smoking intervals in years. According to the obtained data smokers were divided into current smokers (cs) and stop/start smokers (sss), whereas the current smokers were subdivided into heavy current smokers (hcs) and light current smokers (lcs). Significantly, more S were observed in Group A compared with Group B (48/80 vs. 11/32, P < 0.0005), whereas significantly more SI was found in NS compared with S (21/32 vs. 19/48, P < 0.0025). Particularly hcs developed more frequently UI than SI, although this difference had no statistical significance. According to our data smoking women are more likely to develop incontinence, especially motor incontinence, than non-smokers. Heavy smokers seem to tend more to UI.