Women and mothers have traditionally adopted the main role in the rearing of their children. At present, in our country, childbirth gives rise to new circumstances in which most citizens require the help of specialised services to take care of their young.1 The maternity leave period in Spain lasts 16 weeks,2 while it lasts 68 weeks in Sweden.3 The law allows working mothers to devote 1h a day to breastfeeding for 9 months. Thus, child care centres become a social need and demand. According to population surveys, in 2010, 25.01% of women employed out of the home in Spain reported engaging specialised services for the care of their children.4

Child care attendance does have an influence on children's health. A literature review published in 20075 concluded that child care attendance was associated with a significant increase in acute infectious disease in childhood, which also has an impact on society and the immediate household environment.6 Furthermore, it has economic consequences through increased health care costs and the cost associated with parental absences from work.7

In recent years, there has been social debate about the best way to care for children during early childhood. Some studies have been published in support of the psychosocial benefits of attending child care centres, although these benefits have not been proven in populations that are not at psychosocial risk.8 In this context, families often ask the paediatrician about the best way to care for their children. Learning the actual facts will better guide decision-making on this subject while taking into account the circumstances of the household and the health status of each child.

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  To assess the influence of child care attendance on the risk of acute infection, use of pharmacological agents and use of health resources in children younger than 24 months. To establish the influence of other factors.

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  To assess whether the “child care exposure time” factor increases the incidence of infectious diseases and the use of pharmacological agents.

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  To learn the reasons for using child care from participant responses.

We conducted a prospective longitudinal study with two cohorts of children 0–24 months of age that differed in that they attended or did not attend child care (exposure factor); the study was adapted for Asturias from the one designed by the working group of the Asociación Española de Pediatría de Atención Primaria (Spanish Association of Primary Care Paediatrics).9

We collected the data for 1139 children at age 6 months, 1092 at 12 months, and 975 at 24 months. Thus, 14.3% of cases were lost to followup due to three paediatricians changing jobs (7.9%) and participating children moving to new addresses (7.4%).

Children attending child care

By age 2 years, 43.7% of the children in the study attended child care. Fig. 1 shows the number of children first enrolled in child care at intervals of one month of age. The highest peak occurred between 5 and 6 months of age.

Figure 1.

Number of children first enrolled in child care from age 1 month to age 24 months, shown at month-long intervals.

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According to the data we collected, the most common reason for enrolling children in child care (90.7% of cases) was that parents were employed and nobody else was available to care for the child.

Influence of exposure time (age at first enrolment in child care)

Of all children in the sample, 7.3% were attending child care at 6 months, 18.56% at 12 months, 32.51% at 18 months and 43.7% at 24 months.

The mean number of episodes of disease (for all diseases) was lower in children that did not attend child care, and highest in children that started attending child care in the first 12 months of life (Fig. 2).

Figure 2.

Mean number of disease episodes and 95% confidence interval for overall incidence of disease by age at first enrolment in child care.

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In children that had started attending child care by 6 months, the RR of having pneumonia, otitis media, recurrent wheezing or viral illnesses was twice as large (Table 3), and the RR of having bronchiolitis, bronchitis and exanthematous viral illnesses was 1.5 times to twice as large. While the RR for having conjunctivitis, gastroenteritis and common colds was higher in children that attended child care, we found no statistically significant differences based on age at first enrolment.

Table 3.

Relative risk (RR) of suffering the various illnesses by age at first enrolment in child care.

	RR for first enrolment before age 6mN=72(95% CI)	RR for first enrolment at age 6–11mN=109(95% CI)	RR for first enrolment at age 12–17mN=136(95% CI)	RR for first enrolment after age 18mN=109(95% CI)
Bronchiolitis	1.87 (1.42–2.47)	1.52 (1.16 2.01)	1.34 (1.02–1.75)	1.17 (0.85–1.61)
Bronchitis	1.83 (1.41–2.38)	1.93 (1.55–2.4)	1.18 (0.86–1.55)	1.53 (1.19–1.98)
Conjunctivitis	1.58 (1.24–2.03)	1.57 (1.26–1.94)	1.48 (1.2–1.81)	1.27 (0.98–1.62)
Exanthematous viral illnesses	1.74 (1.32–2.29)	1.48 (1.14–1.92)	1.45 (1.13–1.85)	1.28 (0.96–1.71)
Viral pharyngitis	0.92 (0.63–1.34)	1.04 (0.78–1.39)	1.18 (0.92–1.52)	1.22 (0.93–1.58)
Pharyngotonsillitis	1.27 (0.73–2.23)	2.03 (1.39–2.96)	2.02 (1.42–2.87)	1.54 (1.001–2.37)
Gastroenteritis	1.28 (1.03–1.59)	1.25 (1.04–1.51)	1.32 (1.12–1.56)	1.15 (0.94–1.4)
Influenza	1.73 (0.91–3.29)	1.37 (0.75–2.51)	1.28 (0.72–2.27)	1.72 (0.99–2.97)
Laryngitis	1.3 (0.87–1.96)	1.55 (1.13–2.12)	1.21 (0.87–1.67)	0.9 (0.59–1.37)
Pneumonia	2.81 (1.22–6.45)	2.91 (1.43–5.95)	1.69 (0.76–3.79)	2.12 (0.95–4.72)
Otitis media	2.01 (1.59–2.53)	1.82 (1.47–2.26)	1.41 (1.11–1.78)	1.51 (1.18–1.93)
Common cold	1.09 (1.05–1.13)	1.03 (0.98–1.09)	1.01 (0.96–1.07)	1.02 (0.96–1.08)
Recurrent wheezing	2.35 (1.54–3.59)	1.63 (1.05–2.52)	1.66 (1.12–2.48)	1.33 (0.83–2.15)
Sinusitis	1.81 (0.91–3.58)	1.46 (0.77–2.76)	1.81 (1.05–3.09)	1.06 (0.51–2.21)
Viral illness	2.65 (1.23–5.71)	1.09 (0.42–2.82)	1.93 (0.96–3.86)	2.63 (1.25–5.12)

We conducted this study in the PC paediatric offices of the public health system, where 75% to 100% of the children receive care on a regular basis.11–13

The study was conducted by 33 paediatricians and 20 nurses on a voluntary basis. They collected the data in the course of regular paediatric visits to optimise the research capacity of PC paediatrics. The number of participating paediatricians allowed the recruitment of a large sample, but it carried a potential lack of uniformity in diagnostic criteria, which we tried to minimise by establishing definitions before the start of the study.

As for the methodology, the study started with two cohorts that were initially uniform, but exposure to the independent variable (child care attendance) could be associated with other potential confounding factors, so we controlled for all the variables included in the study. The comparison of the two cohorts only revealed significant differences (Table 1) in the history of vaccination against pneumococcus and rotavirus (probably because these vaccines are particularly recommended if children attend child care), in the level of education of fathers and mothers, and in maternal employment, with active employment of the mother being precisely the main reason why children were enrolled in child care.

When it came to the diseases that we analysed, in addition to infectious illnesses we studied the episodes of recurrent wheezing because they are a potentially severe condition with a high prevalence in Asturias (45.6% of children have at least one episode of wheezing in the first 36 months of life).14 Each episode of disease leading to a health visit and resulting in a specific diagnosis was documented a single time, even if the child visited health services more than once for the same episode.

Of all the children in our sample, 43.7% attended child care, similar to the figure reported in “Estadística de las enseñanzas no universitarias,”15 according to which 49.8% of children are enrolled in out-of-home care by 2 years. More than 90% of respondents in our study reported that the reason for sending their child to child care was “being employed and not having anyone to take care of them”.

Consistent with other published studies5,16,17 the incidence of infectious disease was higher in children that attended child care than in those that did not. The relative risks of suffering the different diseases increased in percentages similar to those observed in other studies,8 so that the risk of pneumonia increased by 131%, that of recurrent wheezing by 69%, that of bronchitis by 57% and that of otitis media by 64%. When we transformed the estimated risks to attributable proportions, we found that child care attendance could account for 36% of pneumonias, 23% of recurrent wheezing cases, 30% of viral illnesses, 25% of pharyngotonsillitis cases, and 20% of bronchitis cases.

Since early enrolment in child care increases the “exposure time” to it, and considering that one of the factors with the strongest influence on the incidence of infectious disease is the age at enrolment,18 we calculated the influence of this exposure factor for each age interval on each of the diseases under consideration. We observed that early enrolment in child care (before age 12 months) was associated with an increase in the number of episodes of disease overall (Fig. 2). The RR (Table 3) of suffering from the potentially most severe diseases (pneumonia, otitis media, bronchitis, bronchiolitis and recurrent wheezing) was between 1.5 and 2 times higher in children that started attending child care before age 6 months. The RR of suffering from recurrent wheezing was particularly noteworthy, as it was 1.69 for children that attended child care, and rose to 2.35 in children that started attending in the first 6 months of life.

The RR of contracting pneumonia was 2.31 times higher in children that attended child care, and it increased to 2.81 in children that started attending before age 6 months. Other published works have reported RRs that were higher by factors of 9.4919 and 5.1416; vaccination against pneumococcus, which reaches a coverage of 85% in our region, may play a significant role in this.

One limitation of the study is that we did not take into account the characteristics of the child care centres nor the time spent at the centre by each child; in this regard, a study of similar characteristics that was also conducted in a public health service16 did not find differences in disease incidence depending on the number of hours spent at the child care centre nor the child-to-caregiver ratio in the facility.

We recorded the prevalence of breastfeeding (BF) and the age at which it was discontinued; we did not document exclusive BF, but overall BF. Our analysis of the role of BF on infant morbidity did not reveal a significant protection against infectious diseases. While the protective effect of BF has been widely documented,17,20 our results are similar to those of other studies in developed countries.21,22 Still, the data of our study must be interpreted with caution, as the study was not designed to assess the influence of BF in the morbidity of the sample, which may result in various biases.20,23

The number of visits, both to paediatric clinics and to emergency services, includes every time that the children sought services, even if more than one visit was made for a single episode. The mean number of visits to the emergency room was higher in children that attended child care and increased if attendance started at an early age, with the mean number of visits per year to the emergency room being 1 in children that did not attend child care and 2.3 in children that were enrolled by age 6 months. The number of visits per year to the paediatrician ranged from a mean of 6.3 in children that did not attend child care to a mean of 9 in children that started attending before age 6 months. When it came to the use of medications, 85% of children that attended child care had taken antibiotics and 40% had used bronchodilators, compared to 68% and 22.7%, respectively, of children that were never enrolled in child care.

We feel that it is necessary that we continue to followup the two cohorts to assess their outcomes after school enrolment at 4 and 5 years of age.

Child care attendance is a risk factor for contracting infectious diseases. The risk is higher when children attend at earlier ages; and this is also true of the risk of using pharmacological agents and of the use of emergency room and paediatric services.

Some of these diseases, such as bronchiolitis, recurrent wheezing, pneumonia and otitis, may have a significant impact on the health of the affected children. The high frequency of episodes of disease suffered by children, even if the processes are mild, can affect their development.

Parents and guardians send children to child care mostly because they work and there is nobody else who can take care of them. They should be appropriately informed to be able to make the best choices for their children.

Considering these results, it seems advisable that alternative strategies are considered for taking care of the youngest children, and that public authorities grant parents the opportunity to choose the best type of care for their children, extending the duration of maternity, paternity and breastfeeding leaves, as has already been done in other countries in the European Union.

This study has been funded by the Oficina de Investigación Biosanitaria del Principado de Asturias (Office of Biological Health research of the Principality of Asturias [OIB]) File AP10-11, Resolution of June 25, 2010.

The authors have no conflicts of interest to declare.