Olfactory acuity as a function of age and gender: a comparison of African and American samples

A frequently reported finding in age-related sensory impairment is that olfaction shows consistent and uniform decline with age. In most studies, discerning whether loss in olfaction is due to aging per se or to factors extrinsic to the aging process (e.g., smoking, chemical exposure, head injury) is difficult. Moreover, studies of olfaction have generally relied on data collected from samples drawn primarily from Western societies. As such, little is known regarding differences in olfaction involving non-Western cultures. Using international data from the 1986 National Geographic Smell Survey, responses of 19,219 American respondents and 3,204 respondents from Africa were analyzed. All respondents were screened for factors negatively affecting olfaction. Measures of olfactory acuity included odor detection, identification, intensity, and quality. The odor of interest was androstenone, a scent produced by bacteria on the human body and appearing in sweat. The results indicate that some measures of olfactory acuity tend to decline across age groups, but that this decline is less marked than reported in previous studies. The most important finding is that loss of olfaction is not consistent or uniform between geographic regions of America or Africa, between male vs. female respondents, or among the four measures of olfactory acuity. African respondents (both men and women) had significantly higher percentages of detection than did American respondents, women generally reported higher levels of olfactory functioning than did men, and some measures of olfaction were stable across age groups, or were higher among older respondents (e.g., odor identification).