Systematic review: Symptoms of parental depression and anxiety and offspring overweight

ABSTRACT OBJECTIVE To evaluate the existing literature on the association between parents’ depression and anxiety and their influence on their children’s weight during childhood, identifying possible mechanisms involved in this association. METHODS A systematic search of the literature was conducted in the PubMed, PsycINFO and SciELO databases, using the following descriptors: (maternal OR mother* OR parent* OR paternal OR father) AND (“common mental disorder” OR “mental health” OR “mental disorder” OR “depressive disorder” OR depress* OR anxiety OR “anxiety disorder”) AND (child* OR pediatric OR offspring) AND (overweight OR obes* OR “body mass index” OR BMI). A total of 1,187 articles were found after peer selection. RESULTS In total, 16 articles that met the inclusion criteria were selected for the review. Most of them investigated depressive symptoms and only three, symptoms of maternal anxiety. The evaluated studies suggested a positive association between symptoms of maternal depression and higher risk of childhood obesity. The results diverged according to the chronicity of depressive symptoms (episodic or recurrent depression) and income of the investigated country (high or middle income). Mechanisms were identified passing by quality of parenthood, affecting behaviors related to physical activity and child-feeding, as mediators of the association. CONCLUSIONS We conclude there is evidence of a positive relationship between the occurrence of maternal symptoms of depression and anxiety and childhood obesity. It is emphasized the need for a better understanding on the effect of depressive symptoms and the contextual factors involved in this relationship so that effective intervention strategies can be implemented.


INTRODUCTION
In the last four decades, the number of obese children and adolescents has increased tenfold in the world, from 11 million in 1975 to 124 million in 2016 1 . According to this trend, by 2022 obesity will overcome malnutrition in these phases of life 1 .
In addition to the increase in obesity in the population of children and adolescents, another contemporary global phenomenon is the high prevalence of depression and anxiety disorders noted among young people and adults 2 . Around 4.4% of the world's population is depressed and 3.6% with anxiety disorders, reaching rates of 5.9% and 7.7%, respectively, in the Region of the Americas 2 . Between 2005 and 2015, a worldwide increase of 18% in depression and 15% in anxiety disorders occurred. Despite the differences between countries, in all of them a higher prevalence of both disorders among women is present 3 .
Obesity is a disease with multifactorial etiology 4 , including biological factors such as genetics; environmental factors, such as exposure to obesogenic environments; and psychosocial factors involving feeding, such quality of parenthood 5,6 . Regarding feed, parenthood is manifested by practices like child food control and food use as a reward, being associated with childhood obesity 6,7 .
One factor that directly influences the quality of parenthood and, as a consequence, children's health, is the presence of mental disorders in parents 8 . Mothers with depression, generally, do not provide adequate care to their children, affecting their level of responsiveness to the child 7 . This is reflected in less healthy eating habits and less control over television viewing time and other sedentary behaviors, with low stimulation of recreational activities that require direct maternal involvement 9,10 .
Some studies have shown a relationship between mothers' mental disorders and their children's nutritional status [10][11][12] ; in this sense, some research projects indicate that depressed women in the postnatal period tend to breastfeed for less time than recommended 13 and to have malnourished or obese children [8][9][10] . Due to the increasing rates of depressive and anxiety disorders, it becomes of great relevance the investigation of their consequences in parentchild relations, especially during childhood, period when the child's habits are formed.
This systematic review of the literature aimed to evaluate studies on the association between parental anxiety and depression disorders and their influence on their children's overweight during childhood, identifying possible mechanisms involved in this association.

Study Design
A systematic review of the literature was conducted, aiming to identify original articles that evaluate the association between parental depression and anxiety disorders, and overweight of children aged between 1 and 12 years.

Methods of Search and Studies Selection
The search was conducted between November 2018 and February 2019, in the databases PubMed, SciELO and PsycINFO. The following terms were used for search: (maternal OR mother* OR parent* OR paternal OR father) AND ("common mental disorder" OR "mental health" OR "mental disorder" OR "depressive disorder" OR depress* OR anxiety OR "anxiety disorder") AND (child* OR pediatric OR offspring) AND (overweight OR obes* OR "body mass index" OR BMI). The only restriction was that the studies were conducted in humans. Furthermore, an active search was performed in the references of the selected articles.
The review process was carried out by two independent reviewers (PLM and IDV), whose disagreements were discussed until the consensus on the inclusion of the article to compose the review.

Inclusion Criteria
To be included in this review, the articles had to evaluate both exposure to common mental disorders (any type of depressive and/or anxiety disorders) of parents, and the outcome overweight or obesity of children, defined in the studies by accurate methods of nutritional assessment.
Notably, although depression in pregnancy and postpartum (defined for the purposes of this review as the period between childbirth and at 12 months of age) is not this study focus, studies with these exposures were included when, analyzing longitudinally, the information went further this period.

Exclusion Criteria
Studies that did not present validated depression and anxiety measures, performed exclusively in the prenatal, gestational or within one year after childbirth, as well as those evaluating only children in the first year of life, adolescents, children with health problems that could affect weight or exclusively obese children were excluded.

Quality Assessment
The articles in this review were evaluated for the methodological adequacy used in the sample selection, collection and analysis of data according to the Downs & Black instrument 14 adapted for observational studies, with a scale ranging between 0 and 15 points. The following main aspects of each study were analyzed: definition of objectives and outcome measures; definition of inclusion and exclusion criteria, period and location of the study, sampling procedures (target population and description of the final sample steps), description and/or loss report, variability measures (error/standard deviation and confidence interval), description of outcome measurement methods (personnel training, calibration of appropriate instruments and clothing), and statistical analysis (appropriate statistics, control for confounding factors, and power calculation).

Selection of Studies
A total of 1,196 articles were found, adding the three databases consulted, with a total of 1,187 after deleting duplicates (n = 9). The search strategy identified 1,127 publications in the PubMed database, 48 in the PsycINFO database and 21 in the SciELO database. The selected ones were imported to an EndNote® library and, after reading the titles, 94 records were chosen by consensus among reviewers. The main reason for exclusion was the non-satisfaction of the inclusion criteria related to the outcome or exposure. Based on the abstracts reading, articles were selected for full reading. At this stage, 60 articles were excluded for not evaluating the outcome of interest, leaving 34 for complete reading. After full reading, 19 articles were excluded for the following reasons: evaluation of exposure outside the period of interest (n = 11), population composed only of obese children or at risk of obesity (n = 2), older than required (n = 2), maternal mental disorders analyzed as a moderating variable (n = 1) and not using a cut-off point to classify the nutritional status of children (n = 3). A study was included after active search in the references of the selected articles, adding 16 articles for inclusion in this literature review. Although the bibliographic search covered mothers and fathers, no studies evaluating both or only fathers were found, a fact that restricted this review to the association between maternal mental health and overweight/obesity of children.

Characteristics of the Studies Selected
Studies that met the inclusion criteria for this review were published between 2007 and 2019. From the total, five were carried out in middle-income countries [15][16][17][18][19] , four of them in Brazil and one in Mexico. Eleven were developed in high-income countries 9,12,20-27 , six of them conducted in the United States, two in Australia, two in the United Kingdom and one in Spain. One of the North American studies evaluated only mothers and children of Mexican descent 21 .
In relation to the study populations, generally, longitudinal and transverse samples evaluated population-based samples. The smallest number of participants was 159 individuals 26 and the largest was more than 10,000 mother-child pairs 24 . The only case-control study examined, in total, 100 mother-child pairs 9 .
Symptoms of maternal depression and anxiety were measured during the pregnancy and childhood of the children in only one study 26 , whereas the others were limited to childhood, ranging between the first months after childbirth to approximately the age of 12. In longitudinal studies, the measurements of such disorders were performed mostly two to four times; however, in O'Brien's et al. 20 work, in which ecological factors for the development of obesity in childhood were investigated, maternal depressive symptoms were measured nine times (from six months to 11 years old of children).
The evaluation of these mental disorders occurred in diverse ways, with different instruments used to detect maternal symptoms of depression and anxiety. Out of the 16 studies, only three evaluated anxiety symptoms, in addition to the depressive ones 9,25,27 . In some cases, more than one scale was used in the same study, according to the most indicated for the measurement point. Most of them applied the Center for Epidemiological Studies Depression Scale (CES-D) [16][17][18]20,21,23 . In two of them, in addition to CES-D, other scales were used, depending on the moment of measurement: Edinburgh Postnatal Depression Scale (EPDS) 18 and Depression Scale of the Composite International Diagnostic Interview-Short Form (CIDI-SF) 21 . EPDS was used uniquely in two other surveys 15,19 . For the evaluation of maternal depressive symptoms and anxiety, two studies used the Depression, Anxiety and Stress Scale -21 Items (DASS-21) 26,27 and one study evaluated them with two instruments separately: Beck Depression Inventory-II (BDI) for depressive symptoms and The State Trait Anxiety Inventory (STAI) to assess trait and state of anxiety 8 . Two studies used the scale to assess psychological distress Kessler Psychological Distress Scale (K-6) 24.28 , whereas only one study used the Patient Health Questionnaire (PHQ-9) 25 and another, the depression subscale of the Brief Symptom Inventory-18 (BSI-18) 12 .
For the assessment of child nutritional status, 14 of the 16 studies used body mass index (BMI) according to age and sex. Only two studies used different instruments: one used the weight for age index (W/A) 15 and the other, the weight for length index (W/L) 16 of the children.
In most studies, anthropometric measurements were performed by trained interviewers, but two studies do not report the method 9,19 and, in one study, the measurements were taken from medical records 25 .
In three studies, nutritional status was analyzed longitudinally [21][22][23] , with children aged between nine months and 12 years as their study population. In the rest of them, the outcome was evaluated once, including children aged between six months and 12 years, although most of them were investigated during early childhood and preschool age.
The most used socioeconomic and maternal adjustment variables were schooling, family income, BMI or pre-gestational weight, marital status, employment status and family structure, considering that three or fewer studies also adjusted for other variables, such as: current, previous or during pregnancy smoking; maternal age; ethnicity; parity; socioeconomic status; family support; health insurance; number of residents at home; sanitation scale; use of health services; chronic disease; participation in activities with the child and in the Family Health Program. The most frequently used child-related variables were sex and ethnicity, few studies included birth weight, duration of breastfeeding, single child, age, prematurity, intrauterine growth restriction, recent disease, time in each parent's households when those are divorced, sleep and screen time, introduction of solid foods and food insecurity.
Three studies performed analyses considering mediating variables. Hope et al. 28 considered mediators diet and physical activity of the child, which mitigated risks, but maintained the association between maternal mental disorders, especially with severe symptoms, and childhood obesity. The association lost significance only in the complete model, considering the confounding and mediation variables. The work of Blanco et al. 9 found indirect effects on the association between maternal depression or anxiety and childhood obesity, with emotional over-involvement and maladaptive coping. McConley et al. 12 showed an association between maternal depression and single parenthood with childhood obesity, mediated by the quality of parenthood and its relationship with leisure activities and sedentary behavior of children. The studies demonstrated effects of small magnitude (effect sizes described in Chart 1), suggesting that other factors influence the etiology of childhood obesity.

Main Findings
Regarding the main results related to the association between maternal depressive or anxiety symptoms and overweight in children, we observed that, out of the 16 studies, eight found a positive association between exposure and outcome of interest, one conducted in Brazil 16 and seven in high-income countries 9,12,21-25 . Of the latter, association between maternal depressive symptoms and children's BMI varied according to the chronicity of the symptoms. Three of these studies [21][22][23] , all conducted in the United States, found an association with their children's overweight only when chronicity of maternal depressive symptoms was present (positive measures for symptoms in three follow-ups). However, Morrissey et al. 22 observed this association only in less educated mothers (without higher education) and an inverse association with the more educated ones.
Chart 1 presents the synthesis of the articles included in this systematic review.

Main Findings
This systematic review identified 16 studies evaluating the association between maternal symptoms of depression and/or anxiety and childhood obesity in childhood and found a positive relationship in half of them. This result seems to have been influenced by the quality of parenting of mothers with depressive or anxious symptoms, that is, by the way functions and activities are developed by them. Mothers with depressive symptoms may have lower parental quality, i.e. lower ability to perceive and to interpret signals and communications expressed in their children's behavior, such as less care with meal rules and routines and attention to the quality and quantity of the food consumed 5,29 . The low control of children's diet can lead them to consume less healthy foods 22 when younger and/or allow unhealthy food choices when they are older, factors that corroborate with greater weight gain 30,31 .
Moreover, other behaviors developed and related to maternal depressive/anxiety symptoms may explain the offspring overweight, among them: less control over sleep time 25,29 , lower level of physical activity 27 and longer screen time 12,20,27 . In this sense, some of the studies in this review found a positive association mediated by variables of parental style and child behavior, such as feeding response capacity 26 , shorter sleep time 25 , expressed emotion and maladaptive coping 9 , restriction and monitoring of children's feeding 25,26 , use of food as a reward 25 and lower physical activity of children 12,25,27 .
These practices, which involve direct and active participation of the mother, can be negatively affected by depression due to symptoms such as loss of interest, low energy and fatigue 25,32 . Depressed mothers are generally less responsive to their child and choose coping strategies that require less cognitive effort 3,32 . Permissive parenting, which occurs when the mother places few demands and fails to establish limits on child's behavior, has been positively associated with childhood obesity 3,12,32 . Children of depressed mothers present higher failure rates in weight intervention programs 33 signaling that screening and treatment of maternal depression can improve outcomes related to the nutritional status of children.
Out of the total articles included in this review, five were performed in middle-income countries and only one of them, with a cross-sectional design, found an association between maternal depressive symptoms and overweight of children (between 6 and 24 months of age) 16 . Since low-income families present higher risk of both obesity 1 and maternal depression 3 , a possible explanation for the non-association may be the interaction between socioeconomic and sociocultural factors in determining the effect of maternal mental health on child nutrition 13,15,30 . That is, families with lower economic level, generally, present lower levels of knowledge as well as lower purchasing power, which would affect the adequate child's nutrition 34 . Despite escaping the scope of this review, it is important to highlight that some studies have found a link between maternal depressive symptoms and low weight of the child 15 or lower weight than children of mothers without depressive symptoms 22,31 . However, the relationship seems to occur mainly in lower-income countries or in socioeconomically deprived populations living in higher income countries. BMI (NR) 2-7 years-old Multiple hierarchical regression (S1: family income, maternal education and age; S2: number of children and sex; S3: BMI in early childhood, concern with the child's weight, depression, anxiety and stress) -Maternal depression and anxiety were neither predictors of the child's BMI (β = 0.24 and -0.14, respectively; p > 0.05), nor of the child's maternal feeding practices (pressure to eat, restriction and monitoring). These were also not predictive of childhood BMI. The divergent results between the studies of this review may also reflect methodological differences. One of the methodological factors that varied between them was the moment of evaluation of the child's exposure to maternal mental disorders, ranging between less than 1 year and 12 years. This variation may have interfered with the results in two manners: (1) there may be an age window sensitive to exposure to maternal disorder for further development of obesity, and studies that did not include this sensitive period may not have found an association; (2) this association may be affected by the chronicity of exposure, and the effect would manifest when long exposure to maternal disorders occurs. Corroborating the limitation for the comparison between studies, the period in which maternal symptoms of depression and anxiety were measured did not present a pattern consistent with the BMI measurement of the children. It is not clear which would be the most specific time to measure maternal depressive symptoms to better predict the risk of overweight of children 11,35 .

Limitations of the Studies
Within the limitations, seven authors indicated the losses that occurred in studies with longitudinal design, which often could not be classified 12,15,16,21-23,26,28 . The possibility of non-response bias was also considered 12,22,27 . These biases may affect the outcome of the studies, since mothers with severe depressive symptoms are more likely not to participate or to abandon the study, decreasing the magnitude or even suppressing the association. Another limitation indicated refers to the attribution of causality, inherent to cross-sectional studies, when the measurements of depressive symptoms occurred concomitantly with the performance of the child's anthropometry 8,16,24,25 . Therefore, just as maternal mental disorder can affect the child's weight, mothers of overweight children may have depressive symptoms as a result of this condition, making it impossible to infer causally from the relationship. Despite these limitations, the results of the studies were not invalidated, as the authors used techniques to minimize these problems, such as imputation of missing data and adequate statistical analyses, considering and discussing the limitations in their work.
The fact that information was reported by mothers may have impaired the validity of such data, since those with depressive symptoms are less likely to monitor the activities and behaviors of children. However, it is not clear whether maternal depressive symptoms would lead to excess or to underreport of such routines and behaviors. The focus of the studies on maternal depression was also indicated as a possible source of information error, correlated with the social desirability bias 28 .
Some authors indicated the lack of data on maternal BMI and absence or low quality of information on the child's diet as limitations 12,[16][17][18]20,23,25 . The first may confuse the association or be on the causal path between maternal mental disorder and the child's weight, whereas the second may be a mediator of the association. Limitations in the measures of food consumption were also considered, in some cases explaining the lower magnitude 16,22 or even the absence of association 18,20,27 . Some reasons discussed for the non-association included convenience sample 18 , losses on follow-up 18,20,28 and possible bias in reporting depressive symptoms 18,28 , as well as the possibility of residual confusion 15 . As discussed, these factors may have made the positive result of the association in these studies unfeasible.
Only three studies were found addressing maternal anxiety symptoms, along with depressive ones, which could help in a better understanding of this relationship, since anxious conditions may progress to depression or coexist with it. Only in one of these studies the association was significant 8 , but anxiety and depression were grouped into a single construct defined as maternal psychopathology, making it impossible to attribute the association to each disorder individually.

Strengths of the Studies
Among the strengths of the methodology of the studies, we highlight the large number of individuals surveyed, some of them with national representativeness 12,16,24,28 . As a positive point, most of them collected anthropometric data by trained and standardized interviewers. Longitudinal studies allow establishing a temporal relationship between symptoms of maternal depression and childhood obesity, in addition to the measurement of this symptomatology in many follow-ups, being possible to distinguish between chronic symptoms and episodic ones.
Methodologically, this study sought research that collected information on maternal mental disorders during children's childhood, since early childhood (two to five years of age) was identified as a critical period, in which behaviors (physical activity and diet) that influence obesity 36 are established. This review sought to discuss the results considering that the studies were conducted with populations from different places, factor that may influence the presence or absence of the association and that, consequently, must be weighed in the comparison of results. The heterogeneity between the studies regarding the measurement and categorization of maternal depression and child's age at exposure in the outcome made it impossible to demonstrate a combined estimate of the effects in meta-analysis, which could better explain the results. Regarding the quality of the selected studies, most http://doi.org/10.11606/s1518-8787.2020054001731 presented a good performance in the evaluation performed, and only two 9,19 obtained scores below 10 points, out of a total of 15.
In the same sense of the results described, previous reviews 10, 11,35 found a positive relationship between depression 11,35 and other maternal psychopathologies 11 and obesity in children, with results diverging according to the measure of maternal disorders (pre or postnatal, in isolation or longitudinal) and with the different age groups of children (preschoolers, childhood and adolescence). The studies were conducted in 2012, 2014 and 2015 and included, respectively, 5, 9 and 20 articles. Although they present some differences regarding the inclusion criteria, they highlight the growing interest in the subject in recent years.

Final Remarks
Despite the positive association in most studies, it is necessary to consider disagreements between the results observed, indicating that maternal mental health contributes to the promotion of childhood obesity, but it acts in association with other factors involved in its etiology. For a better understanding of this phenomenon, it is also important to investigate paternal and familial risk factors, such as mental health.
Some coping measures to the exposed problem are recommended, such as screening for maternal mental disorders since prenatal care and, after childbirth, in child's routine consultations. In countries with greater social vulnerability with home health teams, diagnosis and treatment of these disorders can be more easily provided by health professionals' training. Community health interventions in low-and middle-income countries including a maternal mental health component (home visit, empathic listening and cognitive-behavioral techniques) demonstrated success in the decline of depressive symptoms in women in the intervention group [37][38][39] . Based on this review, we conclude that evidence of a relationship between symptoms of maternal chronic depression and children's excess weight exists, mediated by the behaviors of the mother and child. Therefore, it is essential to deepen knowledge about the mechanisms that influence this association so that policies of mental health care of women can be developed, indirectly impacting the nutritional status of children.