Does breastfeeding reduce the risk of sudden infant death syndrome?

BACKGROUND: In the last 20 years, the prevention campaigns to reduce the risk of sudden infant death syndrome were very successful. In some countries the advice to breastfeed is included in the campaigns' messages, but in other countries it is not. OBJECTIVE: To examine the association between type of infant feeding and sudden infant death syndrome. METHODS: The German Study of Sudden Infant Death is a case-control study of 333 infants who died of sudden infant death syndrome and 998 age-matched controls. RESULTS: A total of 49.6% of cases and 82.9% of controls were breastfed at 2 weeks of age. Exclusive breastfeeding at 1 month of age halved the risk, partial breastfeeding at the age of 1 month also reduced the risk of sudden infant death syndrome, but after adjustment this risk was not significant. Being exclusively breastfed in the last month of life/before the interview reduced the risk, as did being partially breastfed. Breastfeeding survival curves showed that both partial breastfeeding and exclusive breastfeeding were associated with a reduced risk of sudden infant death syndrome. CONCLUSIONS: This study shows that breastfeeding reduced the risk of sudden infant death syndrome by approximately 50% at all ages throughout infancy. We recommend including the advice to breastfeed through 6 months of age in sudden infant death syndrome risk-reduction messages.

Prone sleeping position increases the risk of SIDS in the day more than at night.

BACKGROUND: SIDS mortality is higher during the night than in the day. AIM: (1) To examine risk factors for SIDS by time of day and (2) to see if the proportion of deaths at night has changed from prior to the 'Back to Sleep' campaign, which recommended infants sleep supine. METHODS: A large population-based SIDS matched case-control (GeSID) study conducted from 1998 to 2001 (when the prevalence of infants placed prone to sleep was 4.1%). The reference sleep of the controls was matched for the estimated time of death for the case. Risk factors for SIDS were examined for night-time and day-time deaths. The estimated time of death was compared with that from an earlier study in Germany (1990-1994 when prevalence of prone sleeping was 32.2%). RESULTS: There were 333 SIDS cases and 998 matched controls. The increased risk with placed prone to sleep was significantly different during the day [adjusted OR = 18.15 (95% CI = 5.91-55.69)] compared with during the night [adjusted OR = 3.49 (95% CI = 1.46-8.39; p-value for interaction = 0.011)]. There was no significant difference in the other risk factors examined by time of day in the multivariate analysis. The mean time found dead was 09:07. In the earlier study the mean time found dead was 08:54 and the difference was not significant (p = 0.57). CONCLUSIONS: This study confirms previous observations that prone sleeping position carries a greater risk during the day than at night. However, the reduction in infants sleeping prone has not been associated with a reduced number of deaths in the day in Germany.

Nicotine and cotinine in infants dying from sudden infant death syndrome.

The aim of this component of the German Study on Sudden Infant Death was to determine (1) nicotine concentrations in hair (NCH), as a marker of long standing exposure to tobacco, (2) cotinine concentrations in pericardial fluid (CCP) and (3) cotinine concentrations in liquor cerebrospinalis (CCL), the latter measures being markers of recent exposure to tobacco in the last few hours of life. The results obtained were compared with data on parental smoking revealed from interviews. In 100 cases of sudden infant death syndrome, material was taken at autopsy to determine NCH. In 41 cases, NCH and CCP, and in 70 cases, NCH and CCL were determined. Infants of mothers who stated having smoked during pregnancy had higher NCH than infants of non-smoking mothers (p = 0.008). Furthermore, there was a weak but statistically significant relationship between NCH's and the daily cigarette consumption of the mother during pregnancy (n = 64, r = 0.24, p = 0.05). In 43% of infants, nicotine could be detected in their hair, although the mothers had said at the interview that they did not smoke during pregnancy. On the other hand, in 33% of infants whose mother stated they had smoked during pregnancy nicotine was not detectable in the infant's hair. CCP's were strongly correlated with CCL's (r = 0.62, p = 0.0027). For this reason, both parameters were treated as equivalent for the detection of tobacco smoke exposure in the last hours before death. The influence of breast-feeding was evaluated by comparison of the nicotine concentrations in breast fed and non-breast-fed infants from smokers and non-smokers. Fivefold higher nicotine concentrations were determined in non-breast-fed infants of parents who smoked as compared to all other groups. It can be concluded that nicotine intake by passive smoking is much more important than by breast-feeding. We conclude that both interview data and biochemical measures should be sought to understand the true exposure to tobacco smoke.

Do immunisations reduce the risk for SIDS? A meta-analysis.

BACKGROUND: There are claims that immunisations cause sudden infant death syndrome (SIDS), but some studies have found either no association or that they are associated with a reduced risk of SIDS. AIMS: To conduct a meta-analysis examining the relationship between immunisation and SIDS. METHODS: Nine case-controls studies were identified examining this association, of which four adjusted for potential confounders. RESULTS: The summary odds ratio (OR) in the univariate analysis suggested that immunisations were protective, but the presence of heterogeneity makes it difficult to combine these studies. The summary OR for the studies reporting multivariate ORs was 0.54 (95% CI=0.39-0.76) with no evidence of heterogeneity. CONCLUSIONS: Immunisations are associated with a halving of the risk of SIDS. There are biological reasons why this association may be causal, but other factors, such as the healthy vaccinee effect, may be important. Immunisations should be part of the SIDS prevention campaigns.

Sudden infant death syndrome: no increased risk after immunisation.

BACKGROUND: Although previous studies have shown either no association between immunisation and SIDS or even a decreased risk of SIDS, adverse effects, including death, from immunisations continue to cause concern, especially when a new vaccine is introduced. METHODS: A large case control study with immunisation data on 307 SIDS cases and 971 controls. RESULTS: SIDS cases were immunised less frequently and later than controls. Furthermore there was no increased risk of SIDS in the 14 days following immunisation. There was no evidence to suggest the recently introduced hexavalent vaccines were associated with an increased risk of SIDS. CONCLUSIONS: This study provides further support that immunisations may reduce the risk of SIDS.

Are autopsies of help to the parents of SIDS victims? A follow-up on SIDS families.

Little is known about what bereaved parents feel about the autopsy performed on their child. A multi-centre case control study of sudden infant death syndrome (SIDS) victims was carried out in Germany between 1998 and 2001, in which all infants had been autopsied. We performed a follow-up study 4-7 years after the parents had lost their child. A total of 141 parents filled in the questionnaire, which were sent to them by the study centre. Of these, 71% had had another child after the SIDS/sudden unexpected death in infancy. The majority (83%) of the participating parents found the autopsy helped them to cope better with the death. A large proportion (46%) did not want any professional help after the death, and 55% did not wish to have any contact with a self-help group. We conclude that the autopsy is helpful to the majority of bereaved parents. Professional help and self-help groups should be offered to the parents even if the majority in our study did not want to use either.

Infection, health problems, and health care utilisation, and the risk of sudden infant death syndrome.

AIM: To examine whether symptoms suggestive of infection, health problems, and health care utilisation are risk factors for SIDS. METHODS: Matched case-control study with 333 SIDS infants and 998 control infants matched for region, age, gender, and reference sleep. Information was obtained by parental interview, paediatrician completed questionnaire, and hospital admission data. RESULTS: No symptoms were associated with SIDS after adjustment for potential confounders. Illness in the last four weeks as reported by the paediatrician did not differ between cases and controls. Developmental problems and special investigations at any stage of life significantly increased the risk of SIDS (adjusted OR = 2.14 and 2.07). Admission to hospital after the first week of life was associated with an increased risk of SIDS (adjusted OR = 1.88). CONCLUSION: Symptoms of infection and illness are no longer risk factors for SIDS in communities such as Germany where few infants sleep prone. The increased risk of SIDS with developmental problems may indicate that infants which subsequently die of SIDS are abnormal or in some way vulnerable.