Abstract
Background. The incidence of sudden infant death syndrome (SIDS) in the United States has decreased with decreased prone sleeping. Extrapolating from Census Bureau data, ∼7% of SIDS should occur in organized child care settings (ie, child care centers or family child care homes). However, 2 states have reported higher rates of SIDS in child care.
Objectives. To determine the percentage of SIDS deaths occurring in child care settings, and to ascertain associated factors.
Design. A retrospective study of SIDS deaths from January 1995 through June 1997 was conducted. Data were abstracted from SIDS databases in 11 states. Characteristics of SIDS cases occurring in child care settings, including sleep position, were compared with those occurring in the care of parents. Univariate and multiple logistic regression analyses were performed.
Results. A total of 1916 SIDS cases were analyzed for this study. Of these deaths, 20.4% occurred in child care settings. Compared with deaths in the care of parents, those occurring in child care settings were more likely to occur on weekdays between 8:00am and 4:00 pm; infants were older; not black; and their mothers were more educated. Infants in child care were more likely to be found prone in univariate analysis, but the association was not significant in multiple logistic regression analysis. However, in multiple regression analysis, infants in child care were more likely to be last placed prone or found prone, when the usual sleep position was side or supine.
Conclusion. A large proportion (20.4%) of SIDS cases occur in child care settings. Factors associated with SIDS in child care settings include older age, race, and highly educated parents. Previous studies have reported that unaccustomed prone sleeping puts infants at high risk for SIDS; this characteristic was found to be associated with SIDS in child care and may partly explain the high proportion of SIDS cases in child care settings. Parents must discuss sleep position with any caretakers of their infants. In addition, further efforts to educate child care providers about the importance of supine sleep for infants must be ongoing.
- SIDS =
- sudden infant death syndrome
In 1992, the American Academy of Pediatrics published a recommendation to place all healthy infants in the supine or side position for sleep, because the prone infant sleep position is associated with an increased risk of sudden infant death syndrome (SIDS).1 Because subsequent evidence suggested that side position put infants at higher risk than supine, this recommendation was modified in 1996 to state that supine was preferred over the side position for sleep.2 In 1994, a national public education campaign, Back to Sleep, was launched through a coalition of the US Public Health Service, the American Academy of Pediatrics, the Association of SIDS and Infant Mortality Programs, and the SIDS Alliance. Since these recommendations were given and the Back to Sleep campaign was begun, the percentage of infants sleeping prone has decreased dramatically. Recent surveys indicate that the percentage of infants placed prone for sleep by parents decreased from ∼70% in 1992 to 24% in 1996.3–6 Concurrently, the incidence of SIDS decreased ∼40% from 1992 to a rate of .69 per 1000 live births in 1997.7
In the United States, the number of women with children <6 years old in the labor force has increased from 2.9 million in 1960 to 10.3 million in 1996.8 In 1994, there were 1.7 million infants <1 year of age with employed mothers.9 As the number of mothers in the labor force has increased, so has the number of children in child care. From 1977 to 1992, the number of child care centers more than doubled from 25 000 to 51 000.10 According to the US Census Bureau, in 1994, 17% of US infants <1 year of age were attending some type of organized child care, approximately one half in child care centers, and one half in family child care homes (nonrelatives).8,9 If one estimates that infants in child care spend ∼40% of their time (10 hours/day or 38–40 hours/week)11 in that setting, one can extrapolate that ∼7% (17% of infants in child care × 40% of time) of deaths attributed to SIDS can be expected to occur in organized child care settings. However, data from 2 states have suggested a higher rate of deaths in child care settings than would be expected.12This is concerning, especially in light of data that suggest that many child care providers may be placing infants in the prone sleep position at least some of the time.12 Because many infants spend a large percentage of their time in various forms of child care, it is worthwhile to examine both the prevalence of SIDS in these settings and the factors relating to these deaths. We hypothesized that a substantial proportion of SIDS cases occur in child care settings and that infant sleep position may play a role in SIDS occurring in child care.
METHODS
We performed a retrospective surveillance study of all deaths attributed to SIDS from January 1995 through June 1997 in 11 geographically diverse states (Arizona, California, Colorado, Florida, Maryland, Massachusetts, Minnesota, Michigan, Missouri, New Hampshire, and New Jersey). The directors or coordinators of the SIDS programs of these states were members of the Association of SIDS and Infant Mortality Programs. Each state SIDS center received information from the medical examiner regarding all SIDS cases reported in that state. For each death, data were obtained from birth and death certificates and supplemented by parent interview. Trained SIDS grief counselors or investigators from the medical examiner/coroner's office conducted parent interviews within 1 month of the infant's death. Interviews were conducted in the infant's home or by telephone. Data for this study were abstracted from information previously collected by the individual states. No new data were collected. Data collected included birth history, demographic information, smoke exposure, sleep position (usual and last placed), position found, location of death, time of death, caretaker at time of death, prenatal exposures (alcohol, drugs, or tobacco), breastfeeding, medical problems, and recent changes in the child's routine. Location of death was categorized as in a child care setting or not in a child care setting. Not in child care was defined as under the care of a parent or guardian. These deaths usually occurred at home, but some occurred in hotels, the homes of friends, or cars. Child care settings were divided into: at home with a nanny or babysitter (relative or nonrelative), in the care of a relative in the relative's home, in a family child care home, or in a child care center (Table 1).13,14
Definitions for Child Care Arrangements13,14
Frequencies of the demographic variables (means ± standard error of the means) of demographics were tabulated. The outcome measure was location of death (ie, dying of SIDS in a child care setting vs dying of SIDS in the care of the parent/guardian). We performed univariate and multiple logistic regression analyses to identify demographic variables and factors associated with the outcome measure.
This study was approved by the institutional review board of Children's National Medical Center.
RESULTS
Data were provided by the 11 participating states on a total of 2315 SIDS cases, representing all of the SIDS deaths in those states between January 1995 and June 1997. Seventeen percent of the cases (399) were excluded because the location of death was not documented, resulting in a sample size of 1916 cases. The excluded cases were similar to the cases in the sample with regard to age at death, birth weight, gestational age, gender, maternal age, and the day of the week of death. However, the mothers in the excluded cases were less likely to have a high school diploma (P < .001). The total number of SIDS deaths declined each year of the survey, from 91.25 deaths/month (1095 total) in 1995 to 71.67/month (860 total) in 1996, and 59.5/month (357 total) for the first half of 1997.
Of the 1916 cases, 60% were male and 40% female. The mean age at death was 83.5 days (range: 2–365 days). A total of 51.8% were classified as white; 29.4%, black; 11.2%, Hispanic; 2.5%, Asian; 2.1%, Native American; and 1.8%, multiracial or other. Mean birth weight was 3093 g (range: 600-7569 g), and mean gestational age was 39 weeks (range: 23–44 weeks). More than three quarters of the sample (76.6%) was full-term at birth. Mean maternal age was 23.4 years (range: 14–48), and mean paternal age was 27.4 years (range: 14–67). Of the mothers, 37.1% had not completed high school, 35.7% had a high school diploma, and 27.3% had completed some postsecondary school education. Nearly one half of fathers (43%) had a high school diploma, whereas 24.4% had not completed high school and 32.6% had some postsecondary school education. There was documentation of prenatal exposure to tobacco in 39.5% of cases, prenatal alcohol exposure in 11.1%, and prenatal illicit drug exposure in 16.3%. Of the infants dying of SIDS, 64.7% had been exposed to household cigarette smoke, and only 18.8% had been breastfed at any time.
In our sample, 40.1% died during the daytime hours of 8:00am to 4:00 pm, 10.5% from 4:01 pmto midnight, and 28.1% from 12:01 am to 8:00am. The time of death was unknown for 21.2%.
In our sample, 20.4% of deaths occurred in various child care settings, with 1.3% occurring with a nanny/babysitter, 4.3% in a relative's home, and 14.7% in organized child care settings (12.1% in family child care homes and 2.6% in child care centers). The proportion of child care deaths did not increase during the survey, with 203 of 906 deaths (22.41%) in 1995, 130 of 692 (18.79%) in 1996, and 56 of 315 (17.78%) in 1997. The proportion of child care deaths in the individual states ranged from 9.4% (Florida) to 40.2% (Minnesota;Table 2). Approximately 60% of SIDS in child care occurred in family child care homes (Table 2). The prevalence of prone as the usual sleep position was not increased in the child care cohort. Among the infants in child care, 32.0% usually slept prone, 37.7% supine, and 29.5% on the side, compared with 40.7% of those not in child care who usually slept prone, 23.0% supine, and 32.6% on the side. A total of .8% of those in child care and 3.7% of those not in child care had no usual sleep position.
SIDS Deaths, Individual States
When we analyzed demographic characteristics and other factors in a multiple logistic regression model for association with location of death (Table 3), we found that, compared with SIDS that did not occur in child care, SIDS occurring in child care was more likely to occur on weekdays during the hours of 8:00am to 4:00 pm, and infants were more likely to be born at term, older at the time of death, and less likely to have been exposed to tobacco in utero. Black infants were underrepresented and white infants were overrepresented in the group of infants in child care. Parents of infants dying in child care were more likely to be better educated than parents of SIDS victims who died at home.
Factors Associated With SIDS in Child Care
On univariate analysis, infants in child care were more likely to be found or last placed prone. However, when multiple logistic regression was performed, controlling for race, age at death, gestational age, maternal age and education, paternal education, prenatal tobacco exposure, and time of death, this was no longer a significant factor. We did find that being found (P = .011) or last placed (P = .0037) prone when the usual sleep position was side or supine was associated with death in child care. Of the infants who were last placed prone, 59.5% usually slept supine and 40.5% usually slept on the side. Of the infants who were found prone, 38.0% usually slept supine and 62.0% usually slept on the side, suggesting that many of these infants rolled to the prone position while asleep. When the usual sleep position was side or supine, infants in child care were twice as likely to be found prone and 5 times as likely to be last placed prone. The mean ages of infants last placed prone and found prone when the usual position was side or supine were 96.5 days and 99.8 days, respectively; in the multiple logistic regression model, age at death was not a significant factor.
Because child care generally occurs during the hours of 8:00am and 6:00 pm, we conducted a separate analysis of the 1017 deaths occurring during these hours. As expected, a larger percentage in this subsample (306 or 30.1%) died in the care of a child care provider (1.3% with a nanny, 4.7% in a relative's home, 19.5% in a family child care home, and 4.6% in a child care center). However, compared with the entire sample, we found no significant differences in mean age at death, gender, race, parental age, parental educational level, or exposure to prenatal and postnatal tobacco smoke. When multiple logistic regression was performed on this subset, SIDS in child care was significantly more likely to occur in older infants (P = .02), with older (P< .01), more educated (P < .001) mothers. Infants were less likely to be exposed to secondhand smoke (P = .01) and less likely to be black (P < .01). In this cohort, infants in child care were much more likely to be found prone when the usual sleep position was side or supine (P < .005). However, they were not more likely to be last placed prone in this cohort.
For 99 of the infants, information was available regarding the length of time they had been in their individual child care situation. In this small sample, 16 (16.2%) died on the first day in child care, and an additional 18 (18.2%) on days 2 through 7, for a total of 34 deaths (34.4%) occurring in the first week of child care. Of the 99 infants, approximately two thirds of these deaths (63.6%) occurred in family child care homes. When deaths in the first week of child care were compared with deaths after the first week, there was no statistical difference in the location of death. The average age for infants who died on the first day or first week in child care was 106.9 days, compared with the average age of 126.9 days for infants who died after the first week in child care (P = .07). For the 34 who died in the first week in child care, 28 (82.3%) were found prone; of these, 19 usually slept in the supine or side position.
When we stratified the data by child care type, we found that the demographic characteristics of infants who died in a relative's home and those who died in the care of their parents/guardians were similar. The infants who died in the care of a parent, guardian, or relative were more likely to be black, exposed to secondhand smoke, and born to younger and less educated mothers. These characteristics contrasted with those of infants who died in the care of a nanny or while in organized child care, who were more likely to be white, born to older, more educated mothers, and lacking a history of exposure to household smoke.
DISCUSSION
In our study, we found that the proportion of infants dying of SIDS in organized child care settings was disproportionately high, considering the number of infants reportedly in child care. This is especially striking, because the demographic characteristics of this group (white, born to older, more educated parents, and without a history of smoke exposure) would typically place these infants in the lowest risk category for SIDS. These characteristics can primarily be predicted by the demographics of working parents who use child care, in that working parents tend to be older and more educated. In addition, because most families require child care on weekdays during typical work hours, it is to be expected that deaths in child care were associated with these periods. Indeed, when we looked at the subset of deaths taking place between the hours of 8:00 am and 6:00pm, we found that a larger percentage of these deaths occurred in child care settings.
We found that the demographic characteristics of infants cared for by parents were comparable to those in a relative's home. US Census Bureau and other national surveys have reported that low-income and minority families are more likely to rely on relatives to care for their children than are more affluent or white families.9,14,15
It is concerning that 60% of the child care deaths occurred in family child care settings; family child care homes accounted for 12.2% of all SIDS deaths, as opposed to 2.6% occurring in child care centers. According to US Census Bureau data, approximately one half of infants in organized child care are in family child care homes, with the other half in child care centers,8,9 so one would expect similar numbers of SIDS deaths. There are differences between family child care homes and child care centers regarding licensure, regulation, and care provider characteristics that may be important. As opposed to child care centers, family child care providers may or may not be licensed and are less regulated.9 As recently as 1992 (the most current information available), ∼30% of children in family child care homes were cared for by informal or unlicensed providers16; these providers would not be regulated or registered by any agencies. Consequently, there is no systematic approach to dissemination of Back to Sleep information to these providers, compared with those regulated by a state agency. In addition, surveys as recent as 1988 indicated that child care center employees tend to be younger (80% are 40 years old or younger) and well-educated, with more than one half of child care teachers and assistant teachers having attended college.17,18 Although there is no more recent formal data on age and educational level of child care providers, these data from 1988 seem to still be fairly accurate (J. Rickter, personal communication, 1999). Because many of the child care center employees are young mothers,17 they may be more likely to be aware of supine sleeping guidelines from experience with their own children. Family child care providers are often older women (50% are over 50 years old) and tend to be less well-educated.16,19 Eighty percent of family child care providers have children who are school-aged or older,19 so they are unlikely to have had personal experience with supine infant sleeping.
It is unclear why there is such a wide range of child care deaths among the various states. The proportion of child care deaths ranged from 9.4% in Florida to 40.2% in Minnesota. Although there is no state information regarding infants <6 months or 1 year of age in child care, Minnesota has a high proportion of children <6 years with working mothers (69%, compared with a national norm of 60%).20 However, other states with proportions of children <6 years old with working mothers nearly as high, such as New Hampshire (67%), Maryland (66%), and Florida (63%)20 do not have comparable rates of child care deaths. In addition, there is no correlation between the proportion of SIDS in child care and the number of child care centers and licensed family child care providers in each state.20
Although there are guidelines regarding the diagnosis of SIDS,21 we acknowledge that there may be variability among state medical examiners in declaring SIDS as the primary cause of death. Although experts have agreed that complete autopsies should be prerequisite for the diagnosis of SIDS,21 they are by no means universally performed by medical examiners in every state.22 We do not have data regarding the number of autopsies performed in our sample; however, nationally, ∼90% of sudden unexplained infant deaths are autopsied.22
In addition, because this was a retrospective survey, we relied on information available in the participating states. Data collected by the state SIDS centers are considered very accurate, compared with National Center of Health Statistics data.23 In addition, for each SIDS death, the state SIDS center obtains data from birth and death certificates and supplements the information with parent interview. Although we believe that the data collected by the SIDS centers are accurate, we acknowledge that there may be slight reporting bias at several levels and/or inaccuracies in the data obtained from the official documentation. Although it is possible that there may have been some differential reporting of deaths in child care settings (ie, location of death more likely to be reported if it occurred in child care), it is unlikely to account for the large number of child care deaths. In addition, location of death was determined both by death certificate information and parental interview, making differential reporting less likely. However, we acknowledge that some of the data were incomplete. Because of the emotional trauma that would be involved with calling parents several years after the infant's death to ask additional questions, we did not attempt to obtain further information. Therefore, we could not analyze information regarding several important risk factors, including postnatal tobacco exposure; preexisting respiratory conditions; and the presence of quilts, blankets, pillows, and other fluffy items in the crib.
Our conclusion that a disproportionate number of infants die from SIDS in child care is limited by not having living age-matched controls or, alternatively, by not matching the proportion of infants in child care to all deaths by census tract. In addition, our calculation that only 7% of SIDS cases should occur in child care is based on the assumptions that all children in child care are in that setting 40% of the time and that both SIDS and time spent in child care is distributed equally throughout the day. However, neither of these is true, and this may slightly affect the proportion of SIDS that should occur in child care settings.
It is difficult to determine exactly what factors in child care may place infants at risk for SIDS. There may be risk factors intrinsic to infants of working parents that are unrelated to child care. However, it seems that prone sleeping is an important preventable factor. In our sample, we found that infants who died in child care were much more likely than other infants to be unaccustomed to prone sleeping. Studies by Mitchell et al24 and L'Hoir et al25 have reported that infants inexperienced with the prone position may be at extremely high risk of SIDS when placed in the prone position. Many child care providers still may be unaware of the importance of supine sleeping and may place infants prone, when they usually sleep in the supine or side position at home, for reasons of infant comfort.12 In addition, among the 99 infants for whom there was information about the length of time in child care, we found that approximately one third died in their first week in child care, one half of these occurring on the first day in child care. An extremely large percentage (82.3%) of this group was found prone at the time of death; parents reported that most of these infants usually slept in a nonprone position.
The ages of 2 to 4 months have been identified epidemiologically as the highest-risk period for SIDS; part of this may be explained by the phenomenon of unaccustomed prone sleepers. Many infants are now coming home from the newborn nursery as nonprone sleepers; however, ∼20% of these initially nonprone infants change to the prone position at 2 to 4 months of age.26 These infants may be at increased risk because they have not yet developed the upper body muscle strength routinely seen in initially prone sleepers, which may be protective in lifting the head and clearing the airway when sleeping prone.27
Although the national SIDS rate continues to decline, efforts must continue to increase public awareness about the dangers of prone sleeping for infants. Pediatricians must reinforce with parents the importance of continued nonprone sleeping through the first year of life. Parents must discuss nonprone sleep position with any caretakers for their infants, whether these be relatives, child care providers, or occasional babysitters. It must be emphasized that nonprone sleepers may be at greater risk if ever placed prone. In addition, further efforts to educate child care providers must be ongoing.
ACKNOWLEDGMENTS
This study was funded by a grant from the Gerber Foundation.
We thank the staff of the following state SIDS centers for their assistance with data abstraction: Arizona Department of Health Services (Robert Schackner, SIDS Director); California SIDS Program (Ben Carranco, Program Consultant); Colorado SIDS Program (Sheila Marquez, RN, Executive Director); SIDS Program, Florida Department of Health (Annette Phelps, ARNP, MSN); Center for Infant and Child Loss, Maryland (Jean Edwards, Program Coordinator); Massachusetts Center for Sudden Infant Death Syndrome (Mary McClain, RN, MS, Project Coordinator); Michigan Department of Community Health (Cheryl Lauber, SIDS Program Coordinator); Minnesota SIDS Center (Patrick Carolan, MD, Medical Advisor; Kathleen Fernbach, PHN, Director); SIDS Resources, Inc, Missouri (Lori Ahrens, Program Director); New Hampshire SIDS Program (Audrey Knight, MSN, CPNP, Program Coordinator); and SIDS Center of New Jersey (Linda Esposito, RN, Education, Research, Communications Coordinator).
We also thank Bruce Sprague for data management, and Peter Scheidt, MD, and Tina Cheng, MD, for their thoughtful comments on the manuscript.
Footnotes
- Received July 20, 1999.
- Accepted November 29, 1999.
Reprint requests to (R.Y.M.) Department of General Pediatrics and Adolescent Medicine, Children's National Medical Center, 111 Michigan Ave, NW Washington, DC 20010. E-mail: rmoon{at}cnmc.org
The results from this manuscript were presented in part at the Association for SIDS and Infant Mortality Programs meeting; March 19, 1999; Bethesda, MD; the National SIDS Alliance Meeting; April 9, 1999; Atlanta, GA; and the Ambulatory Pediatric Association meeting; May 1, 1999; San Francisco, CA.
REFERENCES
- Copyright © 2000 American Academy of Pediatrics
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