WEATHER TEMPERATURES AND SUDDEN-INFANT-DEATH-SYNDROME - A REGIONAL STUDY OVER 22 YEARS IN NEW-ZEALAND

Study objective-To examine and identify relationships between the sudd en infant death syndrome (SIDS) and environmental temperature in Cante rbury, New Zealand. Design-A retrospective epidemiological study combi ning details of regional hourly temperature and reported SIDS cases. S etting-Canterbury, New Zealand, between 1968 and 1989 inclusively. Par ticipants-All infants reported as dying from SIDS within the Canterbur y region. Main results-The SIDS incidence increased after months with prolonged colder minimum temperatures, confirming the seasonality of S IDS. After adjusting for this seasonality, days that showed little cha nge in hourly temperature and days with warmer minimum temperatures re corded were seen to have a significantly increased the incidence of SI DS. No evidence was found for other relationships between the SIDS inc idence and various measures of daily temperatures on the day of death, over the preceding eight days or between these days. Infants aged 12 weeks and over were more susceptible to SIDS on days when small hourly temperature changes were recorded than their younger counterparts; no other age differences emerged. Conclusions-This study confirmed that the incidence of SIDS is affected by seasonality and temperature on th e day of death. In particular, after a prolonged period of cold minimu m temperatures, infants were most at risk from SIDS on days on which e ither a warmer minimum temperature or little hourly variation in tempe rature were recorded. No other daily or lagged daily temperature facto r (lagged up to eight days before the day of death) was statistically associated with the SIDS incidence. It is suspected that the inconsist ent previously published lag effect findings actually describe some ot her phenomenon such as parental behaviour or infant thermoregulation.