Un metaanálisis asocia el bajo peso al nacer con la depresión en la edad adulta

Low birth weight, preterm birth and small for gestational age association with adult depression: systematic review and meta-analysis

Abstract

Background

There is no consensus on the effects that low birth weight, premature birth and intrauterine growth have on later depression.

Aims

To review systematically the evidence on the relationship of low birth weight, smallness for gestational age (SGA) and premature birth with adult depression.

Method

We searched the literature for original studies assessing the effect of low birth weight, premature birth and SGA on adult depression. Separate meta-analyses were carried out for each exposure using random and fixed effects models.

We evaluated the contribution of methodological covariates to heterogeneity using meta-regression.

Results

We identified 14 studies evaluating low birth weight, 9 premature birth and 4 SGA. Low birth weight increased the odds of depression (OR = 1.39, 95% CI 1.21-1.60). Premature birth and SGA were not associated with depression, but publication bias might have underestimated the effect of the former and only four studies evaluated SGA.

Conclusions

Low birth weight was associated with depression. Future studies evaluating premature birth and SGA are needed.

The lifetime prevalence of depression in low- and high-income countries is 11.1% and 14.6% respectively.1 According to the World Health Organization (WHO), depression is the third leading cause of burden of disease, as measured by Disability Adjusted Lived Years, and in 2030 could be the first.2Evidence suggests that exposures occurring during early years of life or even during pregnancy may have an important role in its development.3-7 Based on the thrifty phenotype hypothesis,8 this programming effect could be a consequence of poor nutrition during fetal life,5,7,9,10 causing an overstimulation of the hypothalamic-pituitary-adrenal axis, which would increase fetal exposure to glucocorticoids and might produce lifelong effects on neurodevelopment, neurogenesis, hippocampal atrophy and lack of brain-derived neurotrophic factor.11,12 Most of the studies evaluating the programming effect of intrauterine growth on depression have used low birth weight as a proxy of intrauterine growth restriction.4,13-19 However, it is important to consider that birth weight is influenced by gestational age and intrauterine growth. According to the thrifty phenotype hypothesis, intrauterine growth retardation would programme the development of depression in adulthood, whereas gestational age would not be associated with depression through the mechanisms suggested by this hypothesis. It has also been suggested that the association between intrauterine growth retardation and depression in adulthood could be due to other mechanisms, such as maternal depression, intimate partner violence and socioeconomic position, which would be related to the occurrence of both low birth weight and depression in adulthood.20-30 Therefore, these conditions should be considered as possible confounders and adjusted in the analysis.

With respect to the association between low birth weight and depression, the evidence is divided. Some studies have reported an association;4,15,17,31-34others have not.14,16,18,19,23,35,36 Few have assessed the independent effect of gestational age13,15,17,23,31,36,37 or intrauterine growth.23,35,36 A systematic review and meta-analysis by Wojcik et al reported a weak association (pooled odds ratio 1.15, 95% CI 1.00-1.32) between low birth weight and later depression.38 This pooled effect may have been overestimated by publication bias. Furthermore, their review included ‘psychological distress’ as one of the outcomes, comprising a broad spectrum of events such as changes in emotional status, discomfort, demoralisation and pessimism about the future, anguish and stress, self-depreciation or a ‘maladaptive psychological functioning in the face of stressful life events’.39,40 In spite of being a symptom of depression, psychological distress does not differentiate between depression and other non-affective disorders such as anxiety, and the inclusion of studies assessing psychological distress may have underestimated the association between birth weight and depression. Finally, as previously mentioned, low birth weight may be due to preterm birth, intrauterine growth retardation or a combination of both, and the review did not disentangle the effect of duration of gestation from that of intrauterine growth.

The aim of our systematic review and meta-analysis was to assess the relationship between low birth weight, SGA and premature birth, and depression in adulthood.