- Split View
-
Views
-
Cite
Cite
Tracy Chu, Martine Hackett, Navpreet Kaur, Housing influences among sleep-related infant injury deaths in the USA, Health Promotion International, Volume 31, Issue 2, June 2016, Pages 396–404, https://doi.org/10.1093/heapro/dav012
- Share Icon Share
Abstract
This article examines the role of housing conditions in sleep-related infant injury death, a leading cause of infant mortality in the USA. The use of an unsafe sleep surface is a major risk factor for sleep-related infant injury. This exploratory study examined contextual circumstances, specifically those related to the physical environment, which may contribute to caregivers' decisions to place an infant on an unsafe sleep surface. It employed a retrospective review of 255 sleep-related infant injury death cases in a large urban area from 2004 to 2010 where an infant was found sleeping on an unsafe sleep surface, including 122 cases where a crib or bassinet was identified in the home. Quantitative findings indicated no differences in demographic or risk characteristics between infants with cribs or bassinets and those without them. Qualitative findings suggested the lack of crib or bassinet use may be related to environmental factors influenced by poverty, specifically crowded living space, room temperature and vermin infestation. This study suggests that infants may be at risk of sleep-related injury deaths even when a crib or bassinet is present in the home and supports the consideration of housing conditions in health promotion efforts to reduce infant mortality. Understanding environmental factors that may contribute to infants sleeping on an unsafe surface can help maternal child health and public health professionals develop more appropriate interventions that address deleterious living conditions.
INTRODUCTION
The World Health Organization (WHO) has recognized the importance of the built environment in health outcomes, especially among vulnerable populations such as children. In some countries, unintentional home injuries are a leading cause of death among children under 5 years of age (World Health Organization, 2010), with infants presenting some of the highest rates of injury death (Imamura et al., 2012).
Although the highest rates of child injury death are found in low-income countries (Peden et al., 2008), in the USA infant injury deaths are on the rise (MacDorman et al., 2013; Murphy et al., 2013). This may be due in part to the narrowing of the diagnostic criteria for sudden infant death syndrome (SIDS) and subsequent diagnostic shift, such that deaths that would have once been attributed to SIDS, a natural cause of death, are now increasingly attributed to other non-SIDS causes such as injury (Malloy and MacDorman, 2005; Shapiro-Mendoza et al., 2009; Krous, 2010; Senter et al., 2011). These ‘new’ causes of infant death include sleep-related injuries, which encompass specific diagnoses such as accidental suffocation and strangulation in bed, as well as undetermined injuries that occur during sleep (Shapiro-Mendoza et al., 2009; Senter et al., 2011).
In New York City (NYC), sleep-related infant injury deaths are a leading cause of infant mortality, occurring at a rate that is four to five times that of SIDS (Fortin et al., 2011). As with SIDS, these injury deaths are sleep-related, i.e. they occur in situations when an infant is known to have been asleep. However, they are distinct from SIDS in that they are attributed to external forces such as suffocation, whereas SIDS is a category of sleep-related death thought to be due to natural causes. Consistent with national trends for infant deaths overall, these injury deaths are highly stratified by race and class, disproportionately affecting African American and low-income communities (Unger et al., 2003; Fortin et al., 2011). As with SIDS, efforts to reduce these types of death have focused on individual-level behaviors such as sleep-related infant care practices.
A primary risk factor for infant sleep-related deaths is the use of an unsafe sleep surface (i.e. any surface other than a crib, bassinet or playpen), often in the context of bed-sharing. Bed-sharing refers to the use of a sleep surface that is shared with an adult or other child and is a factor associated with 64% of sleep-related sudden unexpected infant deaths nationally (Schnitzer et al., 2012). Quantitative and qualitative studies in the USA have sought to identify which parents bed-share with their infants and why they do so. They often focus on behavioral and socio-cultural reasons (Rice and Naksook, 1998; Nelson et al., 2001; Chianese et al., 2009; Joyner et al., 2010; Gaydos et al., 2014; Herman et al., 2014), as well as the protective elements conferred by the practice (Ball and Volpe, 2013). Prior research indicates that, in the USA, inner-city mothers who are single, under 18 years of age, and move frequently were found to be more likely to bed-share (Fu et al., 2008). In addition, African American parents may be more likely to bed-share because of considerations of space and environmental safety (Weimer et al., 2002; Chianese et al., 2009; Joyner et al., 2010).
However, while bed-sharing necessarily involves placing infants on an unsafe sleep surface, many infants are placed to sleep on unsafe surfaces in non-bed-sharing contexts. For example, an infant may be placed to sleep alone on an adult bed or couch. Further, much of the debate on infant sleep location centers on the diversity of cultural conceptions regarding infant care practices such as bed-sharing worldwide, and the appropriateness and efficacy of the health education messaging against these practices (Ball and Volpe, 2013). Few studies have looked at the wider use of unsafe sleep surfaces in general (i.e. regardless of bed-sharing), and even fewer have looked at the role of the housing environment in these decisions, beyond the basic availability of a crib or bassinet (Carlins and Collins, 2007). Very little is known about parents who have cribs or bassinets and their reasons for not using them.
To better understand the context of crib or bassinet use in sleep-related infant injury death cases, this study examined vital statistics data and medical examiner documentation for sleep-related infant injury deaths in NYC where infants were found dead on an unsafe sleep surface, including cases where there was a crib or bassinet present in the home.
METHODS
This study employed a retrospective review of vital statistics data and medical examiner documentation, including death scene investigations, for 255 deaths in NYC from 2004 to 2010 of infants under 1 year of age. The cases selected for review were those that were attributed to ICD-10 codes encompassing asphyxia and undetermined injuries (ICD-10 codes W75, W84, Y33 and Y34), where the infant was known to be sleeping when last seen alive, and where the infant was found to be sleeping on an unsafe sleep surface. This research was approved by the NYC Department of Health and Mental Hygiene's Institutional Review Board.
Data source
This study used data from birth and death certificate records obtained from the NYC Bureau of Vital Statistics and documentation from the NYC Office of the Chief Medical Examiner. In NYC, after an infant has been found dead in the home, a medico-legal investigator typically conducts an investigation of the death scene within 48 h. The investigator interviews caregivers, household residents, police, emergency department physicians and others and completes an extensive questionnaire with both discrete and open-ended items. Through photos and sketches, the investigator also documents the conditions in which the infant was found. In addition to the investigator report, medical examiners typically conduct physical examinations and testing (including a full autopsy and biological and toxicology tests). They also compile information from additional sources, like police reports and any subsequent correspondence between their office and relevant social service agencies. This wide array of data is used by the medical examiner to determine the final cause of death. In the case of these 255 infant injury deaths, these data ruled out the possibility of a natural or biological cause of death, including SIDS.
Variables examined
Birth and death certificate records provided overall demographic information such as mother's age, race/ethnicity, education, nativity, health insurance status, infant sex, gestational age and age at death. Quantitative data extracted from medical examiner records included variables related to the context of the death, such as sleep location, sleep positioning, bed-sharing and presence of excess bedding. Excess bedding adhered to the centers for disease control (CDC)-developed definition used in the Pregnancy Risk Assessment Monitoring System (PRAMS) and indicated the presence of any pillows or stuffed toys in the sleep environment (New York City Department of Health and Mental Hygiene, 2005). Additional variables examined included season of death, infant medical history and infant feeding. Qualitative data were extracted primarily from the narrative sections of the investigator reports and investigators' supplemental memos completed after the initial investigation. In these narratives, investigators often reported on aspects of the physical environment, including the presence of a crib or bassinet. These notations may be made in the narrative description of the home, in their sketch of the room where the infant was found, or in photos.
Data analysis
Variables were extracted from medical examiner records into a Microsoft Access file. The quantitative variables were then exported to the software package SPSS version 20 (IBM Corporation, 2011) and merged to the corresponding vital statistics data. Quantitative analysis, primarily Pearson χ2 analysis, was employed to compare the key demographic and risk factor characteristics between those cases where it was noted in the narrative data that crib or bassinet was present in the home (n = 122) and cases where there was no crib or bassinet in the home (n = 45). As the presence of a crib or bassinet was not a discrete, standardized variable recorded by investigators, in 88 of the 255 cases it was unknown or undocumented whether there was a crib or bassinet in the household.
The qualitative data were exported to the software package Atlas.ti version, 6.2 (ATLAS.ti Scientific Software Development GmbH, 2011) where they were coded first for emerging themes, i.e. ‘open coding’ and then subject to secondary ‘axial coding’. Themes identified during open coding were then used to create discrete categories. Using a summative content analysis approach (Babbie, 1992), themes were developed by first quantifying non-mutually exclusive codes. The authors each coded the data independently and came to consensus regarding each code and their association with one or more of the overarching themes. The themes with at least five codes associated with them were considered robust enough for further analysis.
RESULTS
In an initial qualitative examination of the 255 sleep-related infant injury death cases where the infant was found dead on an unsafe sleep surface, the presence of a crib or bassinet in the home was reported in investigator notes in 47.8% of cases (n = 122). In 17.6% (n = 45) of the 255 total cases it was noted that there was no crib or bassinet in the home. As the presence of a crib or bassinet was not a discrete, standardized variable recorded by investigators, in 34.5% (n = 88) of the cases it was unknown or undocumented whether there was one in the household. Only those cases where the presence of a safe sleep surface in the household was clearly known (n = 167) were explored further in quantitative and qualitative analysis.
Maternal and infant characteristics
The maternal and infant characteristics of the 167 cases of sleep-related infant deaths where the decedent was found in an unsafe sleep surface, and where the presence of a crib or bassinet was documented, are presented in Table 1. Overall, mothers were mostly between the ages of 20 and 34 (72.7%) and identified as Black non-Hispanic (58.8%). Over two-fifths of the mothers had less than a high school education (46.2%). The majority of mothers were born in the USA (73.4%) and had their delivery paid for by Medicaid (72%). The largest proportion of infants were male (54.5%) and died between the ages of 1–4 months (68.3%). The majority of infants were born full-term (78.3%) and had never been admitted to a Neonatal Intensive Care Unit (NICU) (75.3%). Chi-square (χ2) analysis comparing the 122 cases where there was known to be a crib or bassinet in the home and the 45 cases where there was not indicated that there was no statistical significance associated with any of these characteristics.
. | Total, n (%) . | Crib, n (%) . | No crib, n (%) . | p Value . |
---|---|---|---|---|
Maternal and infant characteristics | ||||
Mother's age (n = 161) | ||||
Under 20 years | 25 (15.5) | 19 (16.1) | 6 (14.0) | 0.197 |
20–34 years | 117 (72.7) | 82 (69.5) | 35 (81.4) | |
35+ years | 19 (11.8) | 17 (14.4) | 2 (4.7) | |
Mother's race/ethnicity (n = 160) | 0.112 | |||
White, non-Hispanic | 22 (13.8) | 19 (16.2) | 3 (7.0) | |
Black, non-Hispanic | 94 (58.8) | 67 (57.3) | 27 (62.8) | |
Hispanic | 37 (23.1) | 24 (20.5) | 13 (30.2) | |
Other | 7 (4.3) | 7 (6.0) | 0 (0.0) | |
Mother's education: less than HS (n = 158) | 73 (46.2) | 51 (43.6) | 22 (53.7) | 0.266 |
Mother's nativity: US-born (n = 154) | 113 (73.4) | 83 (72.8) | 30 (75.0) | 0.787 |
Health insurance: Medicaid (n = 161) | 116 (72.0) | 84 (70.6) | 32 (76.2) | 0.487 |
Infant sex: male (n = 167) | 91 (54.5) | 61 (50.0) | 30 (66.7) | 0.055 |
Age at death (n = 167) | 0.565 | |||
Under 28 days | 22 (13.2) | 14 (11.5) | 8 (17.8) | |
28 Days to 4 months | 114 (68.3) | 85 (69.7) | 29 (64.4) | |
4 to 12 months | 31 (18.6) | 23 (18.9) | 8 (17.8) | |
Gestational age: 37+ weeks (n = 161) | 126 (78.3) | 91 (77.1) | 35 (81.4) | 0.561 |
Ever in NICU: no (n = 158) | 119 (75.3) | 85 (73.3) | 34 (81.0) | 0.323 |
Risk factors | ||||
Sleep position: non-supine (n = 158) | 88 (55.7) | 62 (53.0) | 26 (63.4) | 0.248 |
Sleep surface (n = 167) | 0.616 | |||
Adult bed | 143 (85.6) | 106 (86.9) | 37 (82.2) | |
Couch/sofa | 14 (8.4) | 10 (8.2) | 4 (8.9) | |
Other | 10 (6.0) | 6 (4.9) | 4 (8.9) | |
Bed-sharing (n = 167) | 135 (80.8) | 96 (78.7) | 39 (86.7) | 0.245 |
Excess beddinga (n = 139) | 109 (78.4) | 84 (80.0) | 25 (73.5) | 0.425 |
Infant's most recent feeding (n = 151) | 0.193 | |||
Breast milk | 26 (17.2) | 17 (15.5) | 9 (22.0) | |
Formula | 114 (75.5) | 87 (79.1) | 27 (65.9) | |
Other | 11 (7.3) | 6 (5.5) | 5 (12.2) | |
Season of death (n = 167) | 0.493 | |||
Winter | 43 (25.7) | 33 (27.0) | 10 (22.2) | |
Spring | 46 (27.5) | 35 (28.7) | 11 (24.4) | |
Summer | 35 (21.0) | 22 (18.0) | 13 (28.9) | |
Fall | 43 (25.7) | 32 (26.2) | 11 (24.4) |
. | Total, n (%) . | Crib, n (%) . | No crib, n (%) . | p Value . |
---|---|---|---|---|
Maternal and infant characteristics | ||||
Mother's age (n = 161) | ||||
Under 20 years | 25 (15.5) | 19 (16.1) | 6 (14.0) | 0.197 |
20–34 years | 117 (72.7) | 82 (69.5) | 35 (81.4) | |
35+ years | 19 (11.8) | 17 (14.4) | 2 (4.7) | |
Mother's race/ethnicity (n = 160) | 0.112 | |||
White, non-Hispanic | 22 (13.8) | 19 (16.2) | 3 (7.0) | |
Black, non-Hispanic | 94 (58.8) | 67 (57.3) | 27 (62.8) | |
Hispanic | 37 (23.1) | 24 (20.5) | 13 (30.2) | |
Other | 7 (4.3) | 7 (6.0) | 0 (0.0) | |
Mother's education: less than HS (n = 158) | 73 (46.2) | 51 (43.6) | 22 (53.7) | 0.266 |
Mother's nativity: US-born (n = 154) | 113 (73.4) | 83 (72.8) | 30 (75.0) | 0.787 |
Health insurance: Medicaid (n = 161) | 116 (72.0) | 84 (70.6) | 32 (76.2) | 0.487 |
Infant sex: male (n = 167) | 91 (54.5) | 61 (50.0) | 30 (66.7) | 0.055 |
Age at death (n = 167) | 0.565 | |||
Under 28 days | 22 (13.2) | 14 (11.5) | 8 (17.8) | |
28 Days to 4 months | 114 (68.3) | 85 (69.7) | 29 (64.4) | |
4 to 12 months | 31 (18.6) | 23 (18.9) | 8 (17.8) | |
Gestational age: 37+ weeks (n = 161) | 126 (78.3) | 91 (77.1) | 35 (81.4) | 0.561 |
Ever in NICU: no (n = 158) | 119 (75.3) | 85 (73.3) | 34 (81.0) | 0.323 |
Risk factors | ||||
Sleep position: non-supine (n = 158) | 88 (55.7) | 62 (53.0) | 26 (63.4) | 0.248 |
Sleep surface (n = 167) | 0.616 | |||
Adult bed | 143 (85.6) | 106 (86.9) | 37 (82.2) | |
Couch/sofa | 14 (8.4) | 10 (8.2) | 4 (8.9) | |
Other | 10 (6.0) | 6 (4.9) | 4 (8.9) | |
Bed-sharing (n = 167) | 135 (80.8) | 96 (78.7) | 39 (86.7) | 0.245 |
Excess beddinga (n = 139) | 109 (78.4) | 84 (80.0) | 25 (73.5) | 0.425 |
Infant's most recent feeding (n = 151) | 0.193 | |||
Breast milk | 26 (17.2) | 17 (15.5) | 9 (22.0) | |
Formula | 114 (75.5) | 87 (79.1) | 27 (65.9) | |
Other | 11 (7.3) | 6 (5.5) | 5 (12.2) | |
Season of death (n = 167) | 0.493 | |||
Winter | 43 (25.7) | 33 (27.0) | 10 (22.2) | |
Spring | 46 (27.5) | 35 (28.7) | 11 (24.4) | |
Summer | 35 (21.0) | 22 (18.0) | 13 (28.9) | |
Fall | 43 (25.7) | 32 (26.2) | 11 (24.4) |
aExcess bedding adhered to the CDC-developed definition used in the Pregnancy Risk Assessment Monitoring System (PRAMS) and indicated the presence of any pillows or stuffed toys in the sleep environment.
. | Total, n (%) . | Crib, n (%) . | No crib, n (%) . | p Value . |
---|---|---|---|---|
Maternal and infant characteristics | ||||
Mother's age (n = 161) | ||||
Under 20 years | 25 (15.5) | 19 (16.1) | 6 (14.0) | 0.197 |
20–34 years | 117 (72.7) | 82 (69.5) | 35 (81.4) | |
35+ years | 19 (11.8) | 17 (14.4) | 2 (4.7) | |
Mother's race/ethnicity (n = 160) | 0.112 | |||
White, non-Hispanic | 22 (13.8) | 19 (16.2) | 3 (7.0) | |
Black, non-Hispanic | 94 (58.8) | 67 (57.3) | 27 (62.8) | |
Hispanic | 37 (23.1) | 24 (20.5) | 13 (30.2) | |
Other | 7 (4.3) | 7 (6.0) | 0 (0.0) | |
Mother's education: less than HS (n = 158) | 73 (46.2) | 51 (43.6) | 22 (53.7) | 0.266 |
Mother's nativity: US-born (n = 154) | 113 (73.4) | 83 (72.8) | 30 (75.0) | 0.787 |
Health insurance: Medicaid (n = 161) | 116 (72.0) | 84 (70.6) | 32 (76.2) | 0.487 |
Infant sex: male (n = 167) | 91 (54.5) | 61 (50.0) | 30 (66.7) | 0.055 |
Age at death (n = 167) | 0.565 | |||
Under 28 days | 22 (13.2) | 14 (11.5) | 8 (17.8) | |
28 Days to 4 months | 114 (68.3) | 85 (69.7) | 29 (64.4) | |
4 to 12 months | 31 (18.6) | 23 (18.9) | 8 (17.8) | |
Gestational age: 37+ weeks (n = 161) | 126 (78.3) | 91 (77.1) | 35 (81.4) | 0.561 |
Ever in NICU: no (n = 158) | 119 (75.3) | 85 (73.3) | 34 (81.0) | 0.323 |
Risk factors | ||||
Sleep position: non-supine (n = 158) | 88 (55.7) | 62 (53.0) | 26 (63.4) | 0.248 |
Sleep surface (n = 167) | 0.616 | |||
Adult bed | 143 (85.6) | 106 (86.9) | 37 (82.2) | |
Couch/sofa | 14 (8.4) | 10 (8.2) | 4 (8.9) | |
Other | 10 (6.0) | 6 (4.9) | 4 (8.9) | |
Bed-sharing (n = 167) | 135 (80.8) | 96 (78.7) | 39 (86.7) | 0.245 |
Excess beddinga (n = 139) | 109 (78.4) | 84 (80.0) | 25 (73.5) | 0.425 |
Infant's most recent feeding (n = 151) | 0.193 | |||
Breast milk | 26 (17.2) | 17 (15.5) | 9 (22.0) | |
Formula | 114 (75.5) | 87 (79.1) | 27 (65.9) | |
Other | 11 (7.3) | 6 (5.5) | 5 (12.2) | |
Season of death (n = 167) | 0.493 | |||
Winter | 43 (25.7) | 33 (27.0) | 10 (22.2) | |
Spring | 46 (27.5) | 35 (28.7) | 11 (24.4) | |
Summer | 35 (21.0) | 22 (18.0) | 13 (28.9) | |
Fall | 43 (25.7) | 32 (26.2) | 11 (24.4) |
. | Total, n (%) . | Crib, n (%) . | No crib, n (%) . | p Value . |
---|---|---|---|---|
Maternal and infant characteristics | ||||
Mother's age (n = 161) | ||||
Under 20 years | 25 (15.5) | 19 (16.1) | 6 (14.0) | 0.197 |
20–34 years | 117 (72.7) | 82 (69.5) | 35 (81.4) | |
35+ years | 19 (11.8) | 17 (14.4) | 2 (4.7) | |
Mother's race/ethnicity (n = 160) | 0.112 | |||
White, non-Hispanic | 22 (13.8) | 19 (16.2) | 3 (7.0) | |
Black, non-Hispanic | 94 (58.8) | 67 (57.3) | 27 (62.8) | |
Hispanic | 37 (23.1) | 24 (20.5) | 13 (30.2) | |
Other | 7 (4.3) | 7 (6.0) | 0 (0.0) | |
Mother's education: less than HS (n = 158) | 73 (46.2) | 51 (43.6) | 22 (53.7) | 0.266 |
Mother's nativity: US-born (n = 154) | 113 (73.4) | 83 (72.8) | 30 (75.0) | 0.787 |
Health insurance: Medicaid (n = 161) | 116 (72.0) | 84 (70.6) | 32 (76.2) | 0.487 |
Infant sex: male (n = 167) | 91 (54.5) | 61 (50.0) | 30 (66.7) | 0.055 |
Age at death (n = 167) | 0.565 | |||
Under 28 days | 22 (13.2) | 14 (11.5) | 8 (17.8) | |
28 Days to 4 months | 114 (68.3) | 85 (69.7) | 29 (64.4) | |
4 to 12 months | 31 (18.6) | 23 (18.9) | 8 (17.8) | |
Gestational age: 37+ weeks (n = 161) | 126 (78.3) | 91 (77.1) | 35 (81.4) | 0.561 |
Ever in NICU: no (n = 158) | 119 (75.3) | 85 (73.3) | 34 (81.0) | 0.323 |
Risk factors | ||||
Sleep position: non-supine (n = 158) | 88 (55.7) | 62 (53.0) | 26 (63.4) | 0.248 |
Sleep surface (n = 167) | 0.616 | |||
Adult bed | 143 (85.6) | 106 (86.9) | 37 (82.2) | |
Couch/sofa | 14 (8.4) | 10 (8.2) | 4 (8.9) | |
Other | 10 (6.0) | 6 (4.9) | 4 (8.9) | |
Bed-sharing (n = 167) | 135 (80.8) | 96 (78.7) | 39 (86.7) | 0.245 |
Excess beddinga (n = 139) | 109 (78.4) | 84 (80.0) | 25 (73.5) | 0.425 |
Infant's most recent feeding (n = 151) | 0.193 | |||
Breast milk | 26 (17.2) | 17 (15.5) | 9 (22.0) | |
Formula | 114 (75.5) | 87 (79.1) | 27 (65.9) | |
Other | 11 (7.3) | 6 (5.5) | 5 (12.2) | |
Season of death (n = 167) | 0.493 | |||
Winter | 43 (25.7) | 33 (27.0) | 10 (22.2) | |
Spring | 46 (27.5) | 35 (28.7) | 11 (24.4) | |
Summer | 35 (21.0) | 22 (18.0) | 13 (28.9) | |
Fall | 43 (25.7) | 32 (26.2) | 11 (24.4) |
aExcess bedding adhered to the CDC-developed definition used in the Pregnancy Risk Assessment Monitoring System (PRAMS) and indicated the presence of any pillows or stuffed toys in the sleep environment.
Risk factor characteristics
Aside from placing infants on unsafe sleep surfaces such as adult beds or couches, there are a number of other known or suspected risk factors for sleep-related infant injury death related to the sleep environment. These include placing the infant in a non-supine (back) sleep position, bed-sharing and the presence of excess and soft bedding (Scheers et al., 1998; Kemp et al., 2000; Hauck et al., 2003; Carpenter et al., 2004; Pasquale-Styles et al., 2007; Fu et al., 2008; Vennemann et al., 2009; Schnitzer et al., 2012).
Table 1 presents these risk factors among the 167 infants found dead on an unsafe sleep surface, by the presence of a crib or bassinet in the household. In addition, the infants' most recent meal (e.g. breast milk, formula or other) and season of death were also analyzed. Overall, over half of the infants were found in an unsafe, i.e. non-supine position (55.7%), and most were found sleeping on an adult bed (85.6%), were bed-sharing (80.8%) or had excess bedding (78.4%). The majority of infants were fed formula at their last feeding (75.5%), and time of death was distributed equally across four seasons. As with the maternal and infant characteristics, χ2 analysis comparing those 122 infants who were known to have a crib or bassinet in the home and the 45 who did not revealed that there was no statistically significant difference associated with these risk factors. Of note, infants who had a crib or bassinet in the home were not found to be bed-sharing more or less than those who did not have a crib or bassinet in the home, nor had they been breastfeeding more.
In sum, among 167 infants who died while sleeping on an unsafe sleep surface, there was no statistically significant difference between those who were known to have a crib or bassinet in the home and those who did not, neither in terms of maternal and child characteristics nor in other behavioral risk factors. Thus closer examination of the environmental circumstances at the time of death may provide important contextual detail as to why, in 122 cases, infants were placed on an unsafe sleep surface despite the presence of a crib or bassinet in the home.
Emerging qualitative themes related to physical environment
A comprehensive qualitative analysis was conducted of the 122 cases where infants were sleeping on an unsafe sleep surface when a crib or bassinet was known to be present to explore why they were not used. One of the major themes revealed was conditions related to the physical environment. These included crowded living spaces, ambient temperature concerns and rodent and pest infestations. Figure 1 presents these constituent sub-themes and examples.
Lack of space (n = 23, 19% of cases)
Crowded living conditions, with many people sharing a room or apartment, may have been a contributing factor as to why infants were placed to sleep in an unsafe sleep environment. Although there were cribs or bassinets in these homes, crowded living conditions often led to the cribs being used for other purposes to maximize space, often with the infant sharing an adult bed. In the case of one household, which consisted of two adults and three children in a two-bedroom apartment, the investigator noted that the infant was, ‘Co-sleeping but there was a bassinet in apartment; appeared in adequate condition, apparently not used—filled with clothes and other clutter’ (Three-week-old boy found dead while bed-sharing with 24-year-old mother and 37-year-old father). Moreover, some households had multiple young children, and cribs were sometimes occupied by older siblings. In one case where an infant was placed to sleep alone on an adult bed and had fallen and become wedged between the wall and bed, the investigator reported that the parents, ‘Had crib in apartment that was used by 2-year-old sibling. Mother sleeps with deceased (in bed) and 2-year-old sister in crib’ (Four-month-old girl with 29-year-old mother).
Room temperature (n = 5, 4% of cases)
In some instances, parents did not use a crib or bassinet in the home in an effort to keep infants at a safe and comfortable temperature. A lack of heat in the apartment overall led to sharing the bed with an infant for warmth. In the case of a mid-December death of a 5-month-old girl who was bed-sharing with her parents rather than sleeping in the crib in the bedroom, the investigator noted, ‘They slept with the decedent between them because there had been no heat in the apartment for 2 days' (a 5-month-old girl found bed-sharing with a 30-year-old mother and a 26-year-old father). There were also cases of high temperatures, and infants being placed in the one room in the household where air-conditioning was available. In one late-June death, the investigator noted, ‘There was a crib and portable bassinet in one of the bedrooms meant for decedent and one-year-old sister. Decedent usually sleeps in that bassinet but sometimes put in parents’ bed (which is in the living room) when it is hot. Parents have air-conditioning in the living room’ (2-month-old boy found bed-sharing with 22-year-old mother and 32-year-old father).
Rodents and pests in the home (n = 7, 6% of cases)
Another sub-theme identified suggested that the presence of rodents and other pests motivated parents to remove infants from a crib or bassinet in order to protect them from bites or contamination. Infestations of roaches, mice or rats were noted by investigators in a number of cases; in two cases parents identified fear of infants being harmed by these pests as the reason for not using their crib or bassinet. The investigation report explained the infant was, ‘Co-sleeping despite crib in room. … One of the reasons the mother had baby out of crib was because of mouse infestation’ (2-week-old girl found bed-sharing with 23-year-old mother). In another case, an infant boy was found to be bed-sharing with his parents despite having a bassinet in the room. The investigator reported, ‘Parents noticed rats in the apartment and were afraid to put baby to sleep in crib’ (2-month-old boy found bed-sharing with 42-year-old mother and 32-year-old father).
It is important to note that many of the issues related to the physical environment overlapped. For example, crowded living environments often also evidenced problems with heat, or pest infestation. In one household which consisted of two parents and three children sharing a small one-bedroom apartment, a 2-month-old boy was found dead while bed-sharing with his 24-year-old mother. Although there was a crib in the apartment, it was occupied by his 4-year-old and 16-month-old siblings. Moreover, the investigator reported, ‘The mother states sometimes the other children also sleep in the bed with her because there was no heat in the apartment’. The investigator also noted that, although the apartment was neat and clean, ‘Roaches were visible on the walls and floor’.
DISCUSSION
The goal of this study was to examine the characteristics of families of infants who died of sleep-related injuries in NYC, and the housing conditions they experienced. Specifically, this research sought to explore how these factors may have contributed to infants being placed in an unsafe sleep environment, despite having a crib or bassinet in the home. The data overall suggest that access to a safe sleep surface does not ensure that it will be used, as indicated by the high number of such cases. In addition, among infants who died while sleeping outside a crib or bassinet, there were no demographic or risk behavior differences between those who had one in the home and those who did not, suggesting that there are other possible reasons for this practice. Deleterious housing conditions emerged as a possible determinant of health outcomes, in this case, influencing infant care-givers' potentially health-harming decision to place the infant outside of a safe sleep surface. Thus this study suggests pathways by which these living conditions may lead to unsafe infant sleeping environments.
Crowded conditions were identified as an emerging theme in our analysis and a possible factor influencing parental choice about the use of an existing crib or bassinet. In NYC, families similar to the population in this study (e.g. young, African American, less than high school education, low socio-economic status) face an inhospitable housing market. It is estimated that over 80% of all low-income households pay more than 30% of their incomes on rent (New York City Comptroller, 2012). For those who qualify, public housing vacancies are scarce, and federally funded housing subsidy programs have been suspended. The majority of the sample in this study (58.8%) were infants born to African American mothers. Some previous research has indicated that lack of adequate space may be a reason why African American mothers bed-share (Weimer et al., 2002; Joyner et al., 2010), although other studies have not found a relationship between bed-sharing and crowded home conditions (Brenner et al., 2003; Vemulapalli et al., 2004). Of note, these studies dealt specifically with the practice of bed-sharing. The findings in this study suggest that, among sleep-related infant injury deaths in NYC, concerns about crowding and housing quality may influence the use of unsafe sleep surfaces overall, regardless of the intent to bed-share. Moreover, this study included a diverse racial/ethnic sample, thus both expanding on existing research with African American mothers and offering additional insight on non-African American mothers in the urban context.
Concerns about room temperature were also identified as a sub-theme that may explain why some infants were not placed in an existing crib or bassinet. Compared with the group of infants who did not have a crib or bassinet, season of death was not found to be significant, nor was the use of excess bedding. However, these variables may not have captured the complexity of how parents react to unsafe ambient temperatures. In NYC, particularly in low-income communities, tenants often have little control over the temperature inside individual apartments (Morrissey, 2012).
Parents' concerns about infant safety also extended to the need to protect them from pests in the home. In NYC, low-income residents are more likely to report mice or rats in their building; among low-income groups, a higher percentage of Black and Hispanic residents report mice or rats, as compared with low-income Whites (Karpati et al., 2004). Again, the themes identified among some of the families in this study are in concordance with previous findings that concern about vermin may influence African American mothers' decisions to bed-share (Chianese et al., 2009; Joyner et al., 2010) and goes further to indicate that these conditions and reactions may be present regardless of race or bed-sharing status.
Overall, in over four-fifths of the cases examined in this study, infants were known to be bed-sharing and nearly as many evidenced excess bedding, which, in larger studies on infant care practices, has been associated with bed-sharing (Willinger et al., 2003; Colson et al., 2013). Recent research on sleep-related infant deaths has emphasized addressing the multiple levels that influence bed-sharing with infants, such as the use of a socio-ecological model to account for household and societal influences on decisions to bed-share (Salm Ward, 2014), as well as the health belief model to incorporate factors associated with caretaker behavior (Chu et al., 2015). Other researchers have argued for bed-sharing to be considered a non-modifiable infant care practice that is strongly influenced by cultural norms (Owens, 2005) and argue that ethnic and subcultural identity need to inform and shape risk reduction messages (Ball and Volpe, 2013). The findings from this study support health promotion efforts that take an integrated approach to addressing why parents bed-share with their infants, an approach that may include factors related to experiential and socio-cultural characteristics such as convenience, sleep quality and perceived effectiveness of infant care advice, but may also encompass environmental conditions (Hauck et al., 2011; Salm Ward, 2014; Salm Ward and Doering, 2014).
In summary, the three sub-themes explored in this study suggest that social determinants of health-like poverty and housing inequality, rather than socio-cultural beliefs or other infant care practices (such as bed-sharing and breastfeeding) alone, may have a relationship to sleep-related infant deaths in NYC. The WHO's ‘Health in all Policies’ framework proscribes multisectoral action in public policy that promotes health equity (World Health Organization, 2014). These findings suggest that, as new low-income housing units are developed in NYC and other urban areas, health, housing and social welfare policies need to consider how the housing environment influences infant sleep location options for vulnerable families, and how reducing the risk of sleep-related infant deaths may be among the health benefits of ameliorating deleterious living conditions.
CONCLUSION
Sleep-related infant injury deaths are a growing public health concern in the USA and this exploratory study of death cases suggests a link between this type of infant mortality and housing conditions. The prominence of structural-level factors, such as crowded living space, lack of control over ambient room temperature and rodent and pest infestation, and overall poverty indicate that health promotion efforts to reduce the increasing rate of sleep-related injury deaths must encompass the improvement of living conditions in the populations that are most vulnerable in urban communities such as NYC.
In the USA, the evidence of neighborhood contexts as a social determinant of health has been widely discussed (Heymann and Fischer, 2003; Sampson, 2003; Jacob et al., 2013). In urban areas especially, poor housing conditions and poor health have been linked for over a century, with harmful health outcomes disproportionately affecting low-income families (Krieger and Higgins, 2002). The findings of this study suggest that poor or unsafe living conditions experienced by the primarily minority, low-income families of the deceased infants may have rendered the use of the crib or bassinet in the home problematic.
Health promotion efforts that solely discourage bed-sharing or other high-risk behaviors through risk reduction recommendations may not adequately address the overarching context in which these infant deaths occur. Environmental conditions in the home such as indoor air quality and chemical exposures have long been a focus of child health interventions (Sattler et al., 2001; Takaro et al., 2004). We argue that infant injury deaths should fall under a similar rubric. Future promotion efforts should look beyond a health education framework and address the explicit interaction of factors such as housing and income inequality to promote healthier homes and safer conditions for infants. As these infant injury deaths in NYC are not equally distributed among parents who evidence behavioral risk factors, upstream causes that may moderate or mediate environmental conditions in the home need to be investigated and addressed.
ACKNOWLEDGEMENTS
The authors wish to acknowledge the Bureau of Vital Statistics (New York City Department of Health and Mental Hygiene), the Bureau of Maternal Infant and Reproductive Health (New York City Department of Health and Mental Hygiene) and the New York City Office of the Chief Medical Examiner.