SENSITIZATION TO EARLY-LIFE STRESS AND RESPONSE TO CHEMICAL ODORS IN OLDER ADULTS

This study examined the hypothesis that older persons who currently re port illness from environmental chemical odors (cacosmia) may have exp erienced higher levels of stress early in life than did noncacosmic co ntrols. The hypothesis derives from a time-dependent sensitization (TD S) model for cacosmia (Bell et al 1992) that predicts a relative inter changeability of stress and chemicals in inducing and eliciting sensit ized responses in vulnerable individuals. Subjects were selected from those in the top 24% (cacosmic) and bottom 27% (noncacosmic) of a samp le of 192 older adults (mean age 73.8 years) for self-reported frequen cy of illness from the odors of pesticide, car exhaust, paint, perfume , and new carpet. As in previous investigations, cacosmics were younge r, more depressed, and more shy; cacosmics also included a higher prop ortion of women (83% versus 61%). As predicted, cacosmics rated themse lves higher in stress for the first four decades of their lives, but n ot the recent past or present, even after controlling for depression, anxiety, hostility, shyness, age, and gender. Cacosmics reported incre ased prevalence of physician-diagnosed nasal allergies, breast cysts, hypothyroidism, sinusitis, food sensitivities, irritable bowel, and mi graine headache. Only 4% of the overall sample (including 9% of the ca cosmics) acknowledged the controversial physician diagnosis of ''chemi cal sensitivity.'' The replicated observation of greater shyness in ca cosmics is consistent with the ability of hyperreactivity to novelty t o predict enhanced susceptibility to TDS from low levels of pharmacolo gical agents in animals. The findings support a TDS model for cacosmia and suggest that cacosmia as a symptom identifies a large subset of t he nonindustrial population with significant psychophysiological healt h problems that merit further objective examination.