Association of maternal gestational weight gain with intellectual developmental disorder in the offspring: a nationwide follow-up study in Sweden

OBJECTIVES

To investigate the association between maternal gestational weight gain (GWG) and offspring's intellectual developmental disorders (IDD); how this association is modified by maternal early-pregnancy BMI.

DESIGN

Population-based cohort study.

SETTING AND POPULATION

All liveborn singletons with information on maternal GWG in the Swedish Medical Register during 1992-2006 (n = 467 485).

METHODS

We used three GWG classifications, (1) Institute of Medicine (IOM) guidelines ('ideal' GWG: maternal underweight = 12.7-18.1 kg; normal = 11.3-15.9 kg; overweight = 6.8-11.3 kg; obesity = 5.0-9.1 kg), (2) LifeCycle project recommendation ('ideal' GWG: maternal underweight = 14.0-16.0 kg; normal = 10.0-18.0 kg; overweight = 2.0-16.0 kg; obesity class I = 2.0-6.0 kg; obesity class II ≤0.0-4.0 kg; obesity class III ≤0.0-6.0 kg) and (3) GWG centiles. Hazard ratio (HR) and 95% CI for offspring's IDD risk using Cox regression.

MAIN OUTCOME MEASURES

IDD was extracted from Swedish National Patient Register (code ICD-9:317-319/ICD-10:F70-F79).

RESULTS

Forty-one per cent of children were born to mothers with excessive GWG, 32.8% with ideal GWG and 26.2% with inadequate GWG according to IOM guidelines. Inadequate GWG was associated with 21% higher risk of offspring's IDD (95% CI 1.11-1.31) relative to ideal GWG. In contrast, when using the LifeCycle classification, children of mothers with inadequate GWG (HR 1.14, 95% CI 1.05-1.24) or excessive GWG (HR 1.09, 95% CI 1.01-1.17) had higher risks of IDD than those of mothers with ideal GWG. When using GWG centiles, extremely low GWG (<20th centile) and low GWG (20th-40th centile) were associated with elevated offspring's IDD risk. Further stratified analysis by maternal early-pregnancy body mass index (BMI) showed that overweight/obese mothers (BMI ≥25 kg/m² ) with extremely excessive GWG (>25 kg) was associated with an increased offspring's IDD.

CONCLUSION

Our findings suggest that inadequate maternal GWG may increase offspring's IDD risk, irrespective of maternal early-pregnancy BMI. Extremely excessive GWG (>25 kg) may increase offspring's IDD risk, but only among mothers with an early-pregnancy BMI ≥25 kg/m² .

TWEETABLE ABSTRACT

Inadequate maternal weight gain during pregnancy may increase the risk of offspring's intellectual disability, regardless of maternal BMI.

Reproduction after the loss of a child: a population-based matched cohort study

STUDY QUESTION

Is the death of a child associated with higher subsequent fertility?

SUMMARY ANSWER

Women who had lost a child had higher fertility both shortly after the loss and throughout the entire follow-up, independent of the child's age at the time of death.

WHAT IS KNOWN ALREADY

Women who lose a child in the perinatal period often have another child shortly after. However, to our knowledge no previous study has investigated if the death of an older child affects reproductive behavior.

STUDY DESIGN, SIZE, DURATION

The source population for this matched cohort study consisted of all women who gave birth in Denmark from 1978 to 2004 and in Sweden from 1973 to 2002 (N = 1 979 958). Women were followed through to the end of 2008 in Denmark and the end of 2006 in Sweden.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Women who had lost a child before the age of 45 years during the study period (exposed group; n = 36 511) were matched with up to five women who were from the same country and of similar age and family characteristics and had not lost a child at the time of matching (unexposed group; n = 182 522).

MAIN RESULTS AND THE ROLE OF CHANCE

During follow-up, 74% of exposed and 46% of unexposed women had another birth (live- or stillbirth) after a gestation of 28 weeks or more. Compared with unexposed women, exposed women had a shorter interpregnancy interval and, consequently, a higher rate of conception leading to a birth (HR = 5.5 [95% CI: 5.4-5.6]). Rates for exposed women were higher from the first month following the child's death, but the largest difference was between 2 and 3 months after the event. This pattern was independent of the age of the deceased child. Exposed women had more subsequent children than unexposed, leading to a comparable number of living children at the end of follow-up.

LIMITATIONS, REASONS FOR CAUTION

The use of population-based registers allows for the inclusion of virtually all eligible women and nearly complete follow-up; the potential for selection bias is thus negligible. However, only pregnancies that led to a live birth or a stillbirth could be identified, thus fetal losses occurring before week 28 of gestation were missing.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings corroborate the previous evidence suggesting that women try to conceive again shortly after a perinatal death, and many succeed. In addition, this is the first study to investigate the reproductive trajectory after losing an older child. The current study indicates that most women who lose a child between the ages of 6 months and 5 years conceive shortly after the loss, and they have a comparable number of living children at the end of the follow-up compared to those who do not lose a child.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by Grant ERC-2010-StG-260242 from the European Research Council, 176673 and 186200 from the Nordic Cancer Union, DFF-6110-00019 from the Danish Council for Independent Research, 904414 and 15199 from TrygFonden, Karen Elise Jensens Fond (2016), and the Program for Clinical Research Infrastructure (PROCRIN) established by the Lundbeck Foundation and the Novo Nordisk Foundation. The authors do not declare any conflicts of interests.

TRIAL REGISTRATION NUMBER

N/A.

Moderate alcohol consumption and depression - a longitudinal population-based study in Sweden

BACKGROUND AND AIMS

The interrelationship between alcohol consumption and depression is complex, and the direction of the association is unclear. We investigated whether alcohol consumption influences the risk of depression while accounting for this potential bidirectionality.

METHODS

A total of 10 441 individuals participated in the PART study in 1998-2000, 8622 in 2001-2003, and 5228 in 2010. Participants answered questions on their alcohol consumption, symptoms of depression, childhood adversity, and sociodemographic, socioeconomic, psychosocial, and lifestyle factors. A total of 5087 participants provided repeated information on alcohol consumption. We used marginal structural models to analyze the association between alcohol consumption and depression while controlling for previous alcohol consumption and depressive symptoms and other time-varying confounders.

RESULTS

Non-drinkers had a higher depression risk than light drinkers (≤7 drinks/week) (risk ratio: 1.7; 95% confidence interval 1.3-2.1). Consumers of seven-fourteen drinks/week had a depression risk similar to that of light drinkers. Hazardous drinking was associated with a higher risk of depression than non-hazardous alcohol consumption (risk ratio: 1.8, 95% confidence interval: 1.4-2.4).

CONCLUSION

Light and moderate alcohol consumption and non-hazardous drinking were associated with the lowest risk of subsequent depression after accounting for potential bidirectional effects. Hazardous drinking increased the risk of depression.

Alcohol consumption is associated with a lower incidence of acute myocardial infarction: results from a large prospective population-based study in Norway

AIMS

Compelling evidence suggests that light-to-moderate alcohol consumption is associated with a reduced risk of acute myocardial infarction (AMI), but several issues from previous studies remain to be addressed. The aim of this study was to investigate some of these key issues related to the association between alcohol consumption and AMI risk, including the strength and shape of the association in a low-drinking setting, the roles of quantity, frequency and beverage type, the importance of confounding by medical and psychiatric conditions, and the lack of prospective data on previous drinking.

METHODS

A population-based prospective cohort study of 58 827 community-dwelling individuals followed for 11.6 years was conducted. We assessed the quantity and frequency of consumption of beer, wine and spirits at baseline in 1995-1997 and the frequency of alcohol intake approximately 10 years earlier.

RESULTS

A total of 2966 study participants had an AMI during the follow-up period. Light-to-moderate alcohol consumption was inversely and linearly associated with AMI risk. After adjusting for major cardiovascular disease risk factors, the hazard ratio for a one-drink increment in daily consumption was 0.72 (95% confidence interval 0.62-0.86). Accounting for former drinking or comorbidities had almost no effect on the association. Frequency of alcohol consumption was more strongly associated with lower AMI risk than overall quantity consumed.

CONCLUSIONS

Light-to-moderate alcohol consumption was linearly associated with a decreased risk of AMI in a population in which abstaining from alcohol is not socially stigmatized. Our results suggest that frequent alcohol consumption is most cardioprotective and that this association is not driven by misclassification of former drinkers.

Maternal bereavement and the risk of preterm delivery: the importance of gestational age and of the precursor of preterm birth

BACKGROUND

Maternal stress during pregnancy may increase the risk of preterm delivery (PD), but the associations between stress and subtypes of PD are not clear. We investigated maternal loss of a close relative and risks of very and moderately PD (<32 and 32-36 weeks, respectively) and spontaneous and medically indicated PD.

METHOD

We studied 4 940 764 live singleton births in Denmark (1978-2008) and Sweden (1973-2006). We retrieved information on death of women's family members (children, partner, siblings, parents), birth outcomes and maternal characteristics from nationwide registries.

RESULTS

Overall, the death of a close family member the year before pregnancy or in the first 36 weeks of pregnancy was associated with a 7% increased risk of PD [95% confidence interval (CI) 1.04-1.10]. The highest hazard ratios (HR) for PD were found for death of an older child [HR (95% CI) 1.20 (1.10-1.31)] and for death of a partner [HR (95% CI) 1.31 (1.03-1.66)]. These losses were associated with higher risks of very preterm [HR (95% CI) 1.61 (1.29-2.01) and 2.07 (1.15-3.74), respectively] than of moderately preterm [HR (95% CI) 1.14 (1.03-1.26) and 1.22 (0.94-1.58), respectively] delivery. There were no substantial differences in the association between death of a child or partner and the risk of spontaneous v. medically indicated PD.

CONCLUSIONS

Death of a close family member the year before or during pregnancy was associated with an increased risk of PD, especially very PD. Possible mechanisms include both spontaneous and medically indicated preterm birth.

Loss of a close family member the year before or during pregnancy and the risk of placental abruption: a cohort study from Denmark and Sweden

BACKGROUND

Maternal stress during pregnancy is associated with a modestly increased risk of fetal growth restriction and pre-eclampsia. Since placental abruption shares similar pathophysiological mechanisms and risk factors with fetal growth restriction and pre-eclampsia, we hypothesized that maternal stress may be implicated in abruption risk. We investigated the association between maternal bereavement during pregnancy and placental abruption.

METHOD

We studied singleton births in Denmark (1978-2008) and Sweden (1973-2006) (n = 5,103,272). In nationwide registries, we obtained data on death of women's close family members (older children, siblings, parents, and partners), abruption and potential confounders.

RESULTS

A total of 30,312 (6/1000) pregnancies in the cohort were diagnosed with placental abruption. Among normotensive women, death of a child the year before or during pregnancy was associated with a 54% increased odds of abruption [95% confidence interval (CI) 1.30-1.82]; the increased odds were restricted to women who lost a child the year before or during the first trimester in pregnancy. In the group with chronic hypertension, death of a child the year before or in the first trimester of pregnancy was associated with eight-fold increased odds of abruption (odds ratio 8.17, 95% CI 3.17-21.10). Death of other relatives was not associated with abruption risk.

CONCLUSIONS

Loss of a child the year before or in the first trimester of pregnancy was associated with an increased risk of abruption, especially among women with chronic hypertension. Studies are needed to investigate the effect of less severe, but more frequent, sources of stress on placental abruption risk.

Job strain predicts recurrent events after a first acute myocardial infarction: the Stockholm Heart Epidemiology Program

OBJECTIVES

Studies investigating the prognostic role of job stress in coronary heart disease are sparse and have inconclusive findings. We aimed (i) to investigate whether job strain predicts recurrent events after acute myocardial infarction (AMI) and if so (ii) to determine behavioural and biological factors that contribute to the explanation of this association.

DESIGN

Prospective study.

SETTING

Ten emergency hospitals in the larger Stockholm area, Sweden.

SUBJECTS

Non-fatal AMI cases from the Stockholm Heart Epidemiology Program case-control study who were employed and younger than 65 years at the time of their hospitalization (n = 676).

RESULTS

During the 8.5 year follow-up, 155 patients experienced cardiac death or non-fatal AMI; totally 96 patients died, 52 of cardiac causes. After adjustment for potential confounders, patients with high job strain had an increased risk for the combination of cardiac death and non-fatal AMI relative to those with low job strain, the hazard ratio (HR) and the 95% confidence interval (CI) being 1.73 (1.06-2.83). Results were similar for cardiac [HR (95% CI): 2.81 (1.16-6.82)] and total mortality [HR (95% CI): 1.65 (0.91-2.98)]. We found no evidence for mediation from lifestyle, sleep, lipids, glucose, inflammatory and coagulation markers on the association between job strain and the combination of cardiac death and non-fatal AMI.

CONCLUSIONS

Job strain was associated with poor long-term prognosis after a first myocardial infarction. Interventions focusing on reducing stressors at the workplace or on improving coping with work stress in cardiac patients might improve their survival post-AMI.

Effects of a stress management program on vital exhaustion and depression in women with coronary heart disease: a randomized controlled intervention study

OBJECTIVES

Psychosocial factors, including depression and vital exhaustion (VE) are associated with adverse outcome in coronary heart disease (CHD). Women with CHD are poor responders to psychosocial treatment and knowledge regarding which treatment modality works in them is limited. This randomized controlled clinical study evaluated the effect of a 1-year stress management program, aimed at reducing symptoms of depression and VE in CHD women.

DESIGN

Patients were 247 women, < or =75 years, recruited consecutively after a cardiac event and randomly assigned to either stress management (20 2-h sessions) and medical care by a cardiologist, or to obtaining usual health care as controls. Measurements at; baseline (6-8 weeks after randomization), 10 weeks (after 10 intervention sessions), 1 year (end of intervention) and 1-2 years follow-up.

RESULTS

For VE, intention to treat analysis showed effects for time (P < 0.001) and time x treatment interaction (P = 0.005), reflecting that both groups improved over time, and that the decrease of VE was more pronounced in the intervention group. However, the level of VE was higher in the intervention group than amongst controls at baseline, 22.7 vs. 19.4 (P = 0.036) but it did not differ later. The change in depressive symptoms did not differ between the groups.

CONCLUSIONS

CHD women attending our program experienced a more pronounced decrease in VE than controls. However, as they had higher baseline levels, due to regression towards the mean we cannot attribute the decrease in VE to the intervention. Whether the program has long-term beneficial effects needs to be evaluated.