Abstract â–¡ 103

Most cot deaths in the UK now occur in babies living under deprived circumstances. Although many known risk factors are more prevalent in this group, there is some evidence that deprivation per se may be significant, perhaps because of the stress of living under chaotic conditions. Vulnerability must be associated with physiological changes. We have shown previously that risk factors for cot death alter the development of body temperature patterns1, and patterns of urinary excretion of cortisol. In this study we have examined the development of babies from a deprived inner city area.

Babies from a deprived inner city area of Leicester (Jarman index 64.1) were recruited at birth. For each case two controls matched for gestation, parental smoking and birth weight were chosen from our data-base of previous studies. For both cases and controls, the overnight pattern of rectal temperature was monitored at home with a data logger on at least four occasions between 6 and 20 weeks of age, including the night after first routine immunisation against Diphtheria, Tetanus, Pertussis & HIB. At the same time, urine was collected overnight and analysed for cortisol, creatinine and cotinine. Full demographic and perinatal data were collected on each infant, together with a diary of events such as illness and significant life events. Ethical approval and informed consent was obtained for the studies.

In all subjects the minimum rectal temperature at night fell with age. As in our previous work, control infants reached an adult-like night time temperature pattern at about 11 weeks of age2. In the deprived group, temperature fell more slowly with age, so in the range 10-13 weeks, the deprived babies had significantly higher rectal temperatures (P<0.01 Students t-test). At all ages cases excreted significantly more cortisol than controls (P<0.02, Mann Whitney U test), with some deprived infants excreting quantities of cortisol typical of babies under great physical stress (eg such as after surgery). All subjects had significantly elevated rectal temperatures and excreted more cortisol the night after immunisation (p<0.001, Students t-test and P<0.02 Mann Whitney U test respectively). Deprived babies, however, reached significantly higher temperatures and excreted significantly more cortisol (P<0.01 in each case).

Babies living under deprived conditions therefore develop physiological functions more slowly than controls matched for two main risk factors, parental smoking and birth weight, suggesting an effect of deprivation per se. The pattern of urinary excretion of cortisol in these infants suggests considerable physiological stress, perhaps resulting from a chaotic lifestyle. The deprived infants also react significantly more vigorously to the standard immunological challenge of immunisation, suggesting that the development of their immune systems are also different. These differences may relate to their increased vulnerability to cot death.