In a recent study published in the journal Dr Scientific reportResearchers have used self-report and wearable sensors to investigate the relationship between body temperature and depression, examining small differences between waking and sleeping body temperatures and diurnal body temperature amplitudes.
Depression is a significant health problem in the United States, with significant costs for adolescents and young adults. Antidepressant use has expanded in Western countries, yet the effectiveness of existing pharmacologic drugs is limited. Understanding the mechanisms that cause depressive symptoms and identifying modifiable ones is important for developing innovative therapies. Identifying abnormalities associated with depression may lead to a biologically homogeneous subgroup that responds better to therapies targeting specific abnormalities.
Study: Elevated body temperature is associated with depressive symptoms: results from the TemperaturePredict Study. Image credit: DimaBerlin/Shutterstock
About the study
In the current study, researchers explored the relationship between body temperature and depression using data from the TemperaturePredict study, which included more than 20,000 individuals over seven months. Eligible participants were adults who could speak English and had mobile phones that could link to wearable sensors.
The researchers investigated whether higher self-measured body temperature, lower daytime distal body temperature amplitude, and small differences between waking and sleep distal body temperatures were associated with depression severity. The team collected data on self-measured body temperature, wearable sensor-recorded minute-level distal-region body temperature, and self-reported depressive symptoms. Participants measured body temperature once a day with standard thermometers, and wearable sensors recorded minute-level remote temperature measurements using negative temperature coefficient (NTC) thermistors.
The team sent monthly surveys to participants via email along with the Patient Reported Outcome Medical Information System (PROMIS) profile tool for depressive symptoms experienced in the previous month. They converted raw PROMIS depression summary scores to T-scores. In the baseline survey, participants self-reported demographic information such as age and gender.
Researchers used linear regression models to generate odds ratios (ORs) to investigate the relationship between average daily self-reported body temperature and PROMIS T-scores. They calculated the E-value for sensitivity analysis. The team calculated the difference between daily maximum and minimum distal body temperature for all individuals to determine the amplitude for daytime distal body temperature.
The mean age of study participants who self-reported their body temperature was 47 years, 53% were male. Participants completed 3.60 of the seven available PROMIS depression tests. The sensor-recorded body temperature sample consisted of 21,064 participants, with a mean age of 47 years and 56% male. In both unadjusted and adjusted models, the researchers found a positive association between body temperature and depression T-scores. E-values were higher for the effects of age, sex, and body temperature on depression in the linear models.
Average self-reported body temperature by time of day. The figure shows the expected pattern of daily self-reported body temperature reported in the early morning and higher self-reported body temperature during the day. Note. Blue line depicts average self-reported body temperature by time of day (right y axis); Blue shading indicates standard error of the mean. Red shading indicates the number of responses (left Y axis) given per minute (X axis).
Adjusted regressions revealed that body temperature accounted for unique variance in PROMIS T-scores, when known variance was accounted for by age and sex. The OR value for having a mean PROMIS T-score in the moderate versus normal range increased significantly with every 0.10°C increase in mean body temperature (OR, 1.0). PROMIS T-scores (OR, 1.1) were higher in the moderate and severe range than in the normal range.
The team used receiver-operating characteristic (ROC) curves to analyze PROMIS T-scores, revealing improved differentiation between severe, moderate, and mild depression severity levels with ROC curve values of 0.8, 0.7, and 0.6, respectively. Based on the revised model, Youden’s index has 86% sensitivity but only 34% specificity in identifying PROMIS T-scores for depression in the severe range. The unadjusted model performed best (with 63% specificity) with 97% sensitivity to detect PROMIS T-scores in the moderate range.
Distal body temperature during waking hours varied mildly to moderately from the normal range, with the most marked shift occurring from WNL to severe depressive symptoms. Associated statistical tests revealed significant differences in distal body temperature during wakefulness, sleep-wake differences in distal body temperature, and amplitude for daytime distal body temperature, comparing these metrics between participants with severe symptoms and normal ranges. Individuals with severe depressive symptoms showed the highest difference in distal body temperature compared to those with depressive symptoms within the normal range.
Overall, the results of the study showed depressive symptoms to be associated with higher waking body temperatures. Collection of thermometer-measured and wearable sensor-recorded body temperatures supports the association. Distal temperature during sleep was comparable across categories of depression and higher than distal body temperature during wakefulness, suggesting that the sleep-wake discrepancy decreased with increasing severity of depressive symptoms. Those directly targeting the thermoregulatory system have reported antidepressant effects.
- Mason, AE, Kasl, P., Soltani, S., et al. Elevated body temperature is associated with depressive symptoms: results from the TemperaturePredict Study. Science representative 14, 1884 (2024), DOI: 10.1038/s41598-024-51567-w, https://www.nature.com/articles/s41598-024-51567-w