1. Socio-economic determinants of bedsharing in a population-based survey of new Oregon mothers: Analysis of the 1998-1999 Oregon PRAMS Dataset Martin B. Lahr, M.D., M.P.H.* Kenneth D. Rosenberg, M.D., M.P.H. †‡ Jodi A. Lapidus, Ph.D. ‡ * Oregon Department of Human Services, Disability Determination Services † Oregon Department of Human Services, Office of Family Health ‡ Oregon Health & Science University, Dept. of Public Health and Preventive Medicine Eleventh Annual Maternal and Child Health Epidemiology Conference Miami, FL, December 9, 2005

2. BACKGROUND METHODS RESULTS DISCUSSION

3. Bedsharing in context Bedsharing has become a controversial practice, despite its growing prevalence. There is little population-based U.S. data on who bedshares. This information would be useful to: –interpret the significance of case series and anecdotal reports of SIDS deaths. –inform public policy. –guide clinical practice. –help to focus research.

4. BACKGROUND METHODS RESULTS DISCUSSION

5. Oregon PRAMS “Oregon PRAMS, the Pregnancy Risk Assessment Monitoring System, is a project of the DHS Office of Family Health with support from the national Centers for Disease Control and Prevention (CDC). PRAMS collects data on maternal attitudes and experiences prior to, during, and immediately after pregnancy for a sample of Oregon women.”

6. Oregon PRAMS Stratified, random within strata, over-sampling of first five strata 1.Hispanics 2.Non-Hispanic (NH) blacks 3.NH Asians & Pacific Islanders 4.NH American Indians & Alaskan Natives 5.NH whites with low birthweight babies 6.NH whites with normal birthweight babies Weighted 1) to Oregon’s population, 2) for non-response, and 3) for non-coverage

7. Oregon PRAMS Monthly sample from birth certificates Nov. 1998-Oct. 1999 2919 surveys mailed 1867 surveys completed Mixed mode: 1 st mailing – 1308 responses 2 nd mailing - 230 Computer-assisted telephone interview – 329 73.5% strata-weighted response

8. PRAMS Response 1867 completed 53 excluded –babies were no longer alive and/or no longer living with mother 38 excluded –did not indicate whether or not their babies were alive and living with mother 1776 eligible for analysis. 32 did not answer bedsharing question 1758 (99% of those eligible) included in the analysis.

9. PRAMS Question 62. Maternal-infant bedsharing. 62. How often does your new baby sleep in the same bed with you? Check only one.  Always  Almost always  Sometimes  Never “Always” and “almost always” responses combined as “frequent” bedsharing for logistic regression. “Sometimes” and “never” responses combined as “infrequent” bedsharing for logistic regression.

10. Potential factors Race/ethnicity Maternal education Maternal age Parity Marital status Urban vs. mixed density vs. rural county of residence Initiation of prenatal care Adequacy of prenatal care WIC enrollment Birthing hospitals by size Insurance - at labor & delivery and current Family income Infant gender Infant birthweight Bed-sharing status Breastfeeding duration Smoker before, during or after pregnancy PRAMS mode of administration Analysis performed using SUDAAN 8.0.1 Multivariable analysis using reverse stepwise regression, entry p.10

11. BACKGROUND METHODS RESULTS DISCUSSION

12. Bedsharing prevalence among respondents

13. Statistically significant predictors of bedsharing Race/ethnicity Younger maternal age Single marital status Less maternal education Lower annual family income Type of insurance at delivery & currently Longer breastfeeding duration Timing of prenatal care WIC enrollment Prenatal care site Usual infant sleep position Not parity Not maternal smoking

14. Bedsharing & race/ethnicity, univariable logistic regression CharacteristicCrude Odds Ratio (95% CI) Hispanic3.03 (2.29-4.01) Black †4.12 (2.96-5.72) Asian/Pacific Islander †1.90 (1.41-2.56) American Indian/Alaskan Native †1.66 (1.21-2.28) White †1.00 (referent) † non-Hispanic

15. Bedsharing & maternal age & education, univariable logistic regression CharacteristicOdds Ratio (95% CI) Maternal Age 13-19 years2.17 (1.32-3.57) 20-25 years1.05 (0.71-1.56) 26-30 years1.00 (referent) 31-48 years0.85 (0.56-1.31) Maternal Education < 12 years2.77 (1.89-4.05) 12 years1.48 (1.02-2.13) > 12 years1.00 (referent)

16. Bedsharing & marital status & income, univariable logistic regression CharacteristicOdds Ratio (95% CI) Marital Status Single/Divorced2.09 (1.51-2.89) Married/Separated1.00 (referent) Annual family income < $30,0003.06 (1.93-4.85) $30,000-49,9991.43 (0.82-2.48) ≥ $50,0001.00 (referent)

17. Bedsharing & breastfeeding, initiation of prenatal care & WIC CharacteristicOdds Ratio (95% CI) Breastfeeding More than 4 weeks2.11 (1.43-3.09) No more than 4 weeks1.00 (referent) Initiation of prenatal care After the first trimester or none1.46 (1.01-2.10) First trimester1.00 (referent) WIC enrollment Yes2.52 (1.81-3.51) No1.00 (referent)

18. Bedsharing & parity, univariable logistic regression CharacteristicOdds Ratio (95% CI) Parity Firstborn1.00 (referent) Second born0.75 (0.53-1.08) Third born0.91 (0.58-1.42) Fourth or higher0.88 (0.51-1.52)

19. Multivariable logistic, reverse stepwise regression, frequent bedsharing † non-Hispanic CharacteristicOdds Ratio (95% CI) Race/Ethnicity Hispanic1.69 (1.17 – 2.43) Black†3.11 (2.03 – 4.76) Asian/Pacific Islander†2.14 (1.51 – 3.03) American Indian/Alaskan Native†1.17 (0.80 – 1.71) White†1.00 (referent) Breastfeeding  4 weeks 2.65 (1.72 – 4.08) < 4 weeks1.00 (referent) Annual Family Income < $30,0002.44 (1.44 – 4.15) $30,000-49,9991.57 (0.88 – 2.82)  $50,000 1.00 (referent) CharacteristicOdds Ratio (95% CI) Prenatal care site Health Department clinic2.41 (1.41 – 4.14) Private doctor’s or HMO clinic 1.00 (referent) Hospital clinic1.11 (0.67 – 1.85) Other1.68 (0.88 – 3.19) Marital Status Single/divorced1.55 (1.03 – 2.35) Married/separated1.00 (referent)

20. Multivariable logistic regression, frequent bedsharing among respondents with annual family income ≥ $30,000 CharacteristicOdds Ratio (95% CI) Race/Ethnicity Hispanic1.58 (0.79 – 3.16) Black †2.77 (1.43 – 5.36) Asian/Pacific Islander †2.36 (1.47 – 3.78) American Indian/Alaskan Native †1.66 (0.90 – 3.04) White †1.00 (referent) Breastfeeding  4 weeks 2.40 (1.11 – 5.20) < 4 weeks1.00 (referent) Marital Status Single/divorced3.66 (1.62 – 8.27) Married/separated1.00 (referent) † non-Hispanic

21. BACKGROUND METHODS RESULTS DISCUSSION

22. Conclusions Bedsharing is very common in Oregon, as elsewhere. Low income, single, breastfeeding mothers are more likely to bedshare than others. Black and Asian women are more likely to bedshare than others, and this appears to be independent of income level. Hispanics are also more likely to bedshare but SES status is an influence. Non-economic, as well as economic, factors are important determinants of maternal-infant bedsharing. Bedsharing is not solely due to lack of access to cribs and provision of cribs will not eliminate bedsharing.

23. Published studies on SIDS & bedsharing Summary of studies –8 uncontrolled case series raising a question of risk –9 large case control studies 3 did not report results stratified by maternal smoking status but none found an association between bedsharing & SIDS (1,2,3) 6 provided stratified results –3 found no association between SIDS and bedsharing among nonsmoking mothers; among smoking mothers, risk was increased (4,5,6) –1 found an increased risk for infants 11 weeks old; and an increased risk for smoking mothers but not nonsmokers (7) –2 found no association between SIDS and bedsharing among nonsmoking mothers of infants > 11 weeks old but did find a risk for infants < 8-11 weeks old and for all infants of smoking mothers (8,9)

24. SIDS and diagnostic drift There is good evidence of diagnostic drift –The decline in overall postneonatal mortality has been less than that of SIDS mortality –Since 1999, SIDS mortality has continued to fall, while postneonatal mortality has been flat and other causes of sudden unexpected death have risen The evidence regarding bedsharing is clear and consistent and unlikely to have been significantly affected by diagnostic drift Further studies must take this phenomenon into account

25. Crib provision programs Valuable public health campaign? Culturally insensitive? Supported by scientific evidence? Bedsharing appears to be the result of combination of economic, cultural and racial/ethnic factors Follow up study in St. Louis found that less than half of those given cribs were using them regularly

26. Recommendations The popularity of bedsharing must be considered when evaluating uncontrolled studies or anecdotal reports. The relative importance of cultural and economic factors in choice of bedsharing should be further explored. Bedsharing recommendations should be based on the best available scientific evidence, not prejudice or “common sense.”

27. Recommendations Cultural values should not be imposed on diverse groups, without good scientific evidence; bedsharing should be a matter of choice, unless and until there is scientific justification to discourage all bedsharing. –There is strong evidence that bedsharing by smoking mothers is a significant risk for SIDS. –There is some evidence that bedsharing with infants < 3 months of age by nonsmoking mothers is a risk for SIDS and this practice should be discouraged based on current scientific evidence. –There is no evidence that maternal bedsharing with infants > 3 months of age by nonsmoking mothers is a significant risk for SIDS. –Cribs should be a choice and an option, not an obligation

28. References 1. Klonoff-Cohen H, Edelstein SL. Bed sharing and the sudden infant death syndrome. Br Med J 1995;311:1269-72. 2. Hauck FR, Herman SM, Donovan M, al. et. Sleep environment and the risk of Sudden Infant Death Syndrome in an urban population: the Chicago Infant Mortality Study. Pediatrics 2003;111:1207-14. 3. Brooke H, Gibson A, Tappin D, Brown H. Case control study of sudden infant death syndrome in Scotland, 1992-1995. Br Med J 1997;314:1516-20. 4. Scragg RK, Mitchell EA, Taylor BJ, al. et. Bed sharing, smoking, and alcohol in the sudden infant death syndrome. Br Med J 1993;307:1312-8. 5. Mitchell EA, Tuohy PG, Brunt JM, et al. Risk factors for sudden infant death syndrome following the prevention campaign in New Zealand: a prospective study. Pediatrics 1997;100:835-40. 6. Fleming PJ, Blair PS, Bacon C, et al. Environment of infants during sleep and risk of the sudden infant death syndrome: results of 1993-5 case-control study for confidential inquiry into stillbirths and deaths in infancy. Br Med J 1996;313:191-5. 7. McGarvey C, McDonnell M, Hamilton K, O’Regan M, Matthews T. An eight-year study of risk factors for SIDS: Bedsharing vs. non bed-sharing. Arch Dis Child 2005 (doi:10.1136/adc.2005.074674):1-7. 8. Carpenter RG, Irgens LM, Blair PS, et al. Sudden unexplained infant death in 20 regions in Europe: case control study. Lancet 2004;363:185-91 9. Tappin D, Ecob R, Brooke H. Bedsharing, roomsharing, and Sudden Infant Death Syndrome in Scotland: a case-control study. J Pediatr 2005;147:32-7.