Using approximated ambient temperature for the date and geographic location of the examination in UAVCW and STRIDE, a rise in ambient temperature of one degree Celsius correlated with 0.001 degree (p<0.001) and 0.0004 degree (p=0.013) increases in body temperature in UAVCW and STRIDE, respectively. The month of the year had a relatively small, though statistically significant, effect on temperature in all three cohorts, but no consistent pattern emerged ( Figure 1-figure supplement 5).
In both STRIDE and a one-third subsample of NHANES, we confirmed the known relationship between later hour of the day and higher temperature: temperature increased 0.02☌ per hour of the day in STRIDE compared to 0.01☌ in NHANES ( Figure 1, Figure 1-figure supplement 2, Figure 1-figure supplement 4). We speculated that the differences observed in temperature between the 19 th century and today are real and that the change over time provides important physiologic clues to alterations in human health and longevity since the Industrial Revolution. Human body temperature is a crude surrogate for basal metabolic rate which, in turn, has been linked to both longevity (higher metabolic rate, shorter life span) and body size (lower metabolism, greater body mass). The question of whether mean body temperature is changing over time is not merely a matter of idle curiosity. These infectious diseases and other causes of chronic inflammation may well have influenced the ‘normal’ body temperature of that era. Wunderlich obtained his measurements in an era when life expectancy was 38 years and untreated chronic infections such as tuberculosis, syphilis, and periodontitis afflicted large proportions of the population ( Murray et al., 2015 Tampa et al., 2014 Richmond, 2014).
oral today) or the quality of thermometers and their calibration ( Mackowiak, 1997). Remaining unanswered is whether the observed difference between Wunderlich’s and modern averages represents true change or bias from either the method of obtaining temperature (axillary by Wunderlich vs. Recently, an analysis of more than 35,000 British patients with almost 250,000 temperature measurements, found mean oral temperature to be 36.6☌, confirming this lower value ( Obermeyer et al., 2017). A compilation of 27 modern studies, however ( Sund-Levander et al., 2002), reported mean temperature to be uniformly lower than Wunderlich’s estimate. In 1851, the German physician Carl Reinhold August Wunderlich obtained millions of axillary temperatures from 25,000 patients in Leipzig, thereby establishing the standard for normal human body temperature of 37☌ or 98.6 ☏ (range: 36.2–37.5☌ ) ( Mackowiak, 1997 Wunderlich and Sequin, 1871).
0 kommentar(er)
