The rate and magnitude of atmospheric pressure change that aggravate pain-related behavior of nerve injured rats

Goreisan regulates cerebral blood flow according to barometric pressure fluctuations in female C57BL/6J mice

Goreisan is a Kampo medicine used to treat headaches associated with climate change. Here, by using an implantable complementary metal-oxide-semiconductor (CMOS) device, we evaluated the effects of Goreisan and loxoprofen on cerebral blood flow (CBF) dynamics associated with barometric pressure fluctuations in freely moving mice. In the vehicle group, decreasing barometric pressure increased CBF that was prevented by Goreisan and loxoprofen. Notably, Goreisan, but not loxoprofen, reduced CBF after returning to atmospheric pressure. These results indicate that, unlike the mechanism of action of antipyretic analgesics, Goreisan normalizes CBF abnormalities associated with barometric pressure fluctuations by actively reducing CBF increase.

Pain and Weather associations - Action Mechanisms; Personalized profiling

It is a well-known hypothesis that weather can influence human health, including pain sensation. The primary meteorological factors are atmospheric pressure, wind, humidity, precipitation, and temperature, which vary from the climate and seasons, but the parameters of space weather (e.g., geomagnetic and cosmic ray activities) also may affect our body condition. Despite a significant number of experimental studies, reviews, and meta-analyses concerning the potential role of weather in pain sensitivity, the findings are heterogeneous and lack consensus. Therefore, rather than attempting a comprehensive analysis of the entire literature on the effects of weather on different pain types, this study highlights the potential action mechanisms of the meteorological factors, and the possible causes of the controversial results. The few data available about the individual evaluations are discussed in detail to reveal the significance of the personalized analysis of the possible relationships between the most available weather parameters and the pain scores. The use of special algorithms may enable the individual integration of different data for a precise outcome concerning the link between pain sensitivity and weather parameters. It is presumed that despite the high level of interindividual differences in response to meteorological parameters, the patients can be clustered in different groups based on their sensitivity to the weather parameters with a possible disparate treatment design. This information may help patients to control their daily activities and aid physicians to plan more valuable management for patients with pain states when the weather conditions change.

Retrospective Longitudinal Study on Changes in Atmospheric Pressure as a Predisposing Factor for Odontogenic Abscess Formation

In our retrospective longitudinal study based on the data from 292 patients, we wanted to investigate whether there was an association between weather conditions and the occurrence of odontogenic abscesses (OA) requiring hospitalization. In the adult group (249 patients), the incidence of severe OA was highest in winter (32.9%) during January (11.6%), with the most common localizations being the perimandibular (35.7%) and submandibular (23.3%) regions. We found that changes in mean daily atmospheric pressure five days before hospitalization showed a positive association with the occurrence of OA, especially pressure variations greater than 12 hPa. Atmospheric pressure changes two and five days before hospitalization were also found to be moderate predictors of complications during treatment. Antibiogram analysis revealed resistance of streptococci to clindamycin in 26.3%. In the pediatric group, OA were also most frequent in winter (30.2%), and the perimandibular region (37.2%) and the canine fossa (20.9%) were the most frequent abscess localizations, while an association with meteorological parameters was not demonstrated. Clinical experience teaches us that weather change influences the occurrence of severe OA requiring hospitalization, which we confirmed in this research. To our knowledge, our study is the first to provide a threshold and precise time frame for atmospheric pressure changes.

To tolerate weather and to tolerate pain: two sides of the same coin? The Tromsø Study 7

ABSTRACT

It is a common belief that weather affects pain. Therefore, we hypothesized that weather can affect pain tolerance. This study used data from over 18,000 subjects aged 40 years or older from the general population, who participated in the Tromsø Study 7. They underwent a one-time assessment of cuff algometry pressure pain tolerance (PPT) and cold pain tolerance (CPT), tested with a cold pressor test. The results showed a clear seasonal variation in CPT. The rate of withdrawal in the cold pressor test was up to 75% higher in months in the warmer parts of the year compared with January 2016. There was no seasonal variation in PPT. The study not only found a nonrandom short-term variation in PPT but also indications of such a variation in CPT. The intrinsic timescale of this short-term variation in PPT was 5.1 days (95% % confidence interval 4.0-7.2), which is similar to the observed timescales of meteorological variables. Pressure pain tolerance and CPT correlated with meteorological variables, and these correlations changed over time. Finally, temperature and barometric pressure predicted future values of PPT. These findings suggest that weather has a causal and dynamic effect on pain tolerance, which supports the common belief that weather affects pain.

Does change in barometric pressure per given time at high altitude influence symptoms of acute mountain sickness on Mount Fuji? A pilot study

Background

Acute mountain sickness (AMS) is a common, transient condition characterized primarily by headaches, and it can also be associated with fatigue, dizziness, and nausea with vomiting. The symptoms of AMS are most pronounced after the first night spent at a new altitude. At sea level, changes in barometric pressure per given time have been associated with migraine headaches. We sought to investigate whether changes in barometric pressure, subjective sleep quality index, and other candidates contributed to the risk of developing AMS on Mount Fuji in Japan.

Method

We surveyed 353 trekkers who stayed overnight at a mountain lodge before summitting Mount Fuji. We collected information regarding sex, age, sleeping altitude at the hut, and perceived sleep quality index including sleep time. AMS was assessed with the Lake Louise Scoring system. Barometric pressure and ambient temperature were collected at the 5th station (2305 m) and at the summit (3776 m).

Result

The overall prevalence of AMS in our cohort was 41.4% (Lake Louise Score ≥ 3 with headache, n=146). Using logistic regression, three factors were combined to generate a robust model for determining the risk of AMS (with or without AMS). These included (1) Δ barometric pressure during ascent per hour, (2) sleepiness on rising, and (3) sleep refreshment assessed by perceived sleep quality index.

Conclusion

These results suggest that climbers who stay overnight at the lodge should keep a better physical condition of sleep, and would pay attention to information of barometric pressure condition to decrease their risk of AMS at the summit of Mount Fuji. Our observatory data indicated that an overnight staying in half way up to the summit does not necessarily reduce the AMS risk in both sexes and irrespective of age, at least, until 3776 m elevation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40101-021-00256-y.

Craniofacial sensations induced by transient changes of barometric pressure in healthy subjects – A crossover pilot study

Background:

Changes in atmospheric pressure are suggested to trigger headaches. This pilot study was made to determine craniofacial sensations accompanying short phases of changing barometric pressure.

Methods:

In a crossover design, 15 adult healthy subjects were exposed in a climate chamber to 8 min phases of barometric pressure lowering by 0, 20 and 40 hPa. The subjects rated their sensations of ear pressure, head compression and the occurrence of headache every minute on a visual analogue scale (VAS, range 0–10). Pulse rate was recorded as a parameter for autonomic functions.

Results:

Nearly all subjects experienced ear pressure and half of them compression of their head at variable degrees. These sensations started in most subjects during the phase of lowering barometric pressure and increased to an average rating of about 3 VAS when returning to ambient atmospheric pressure. Heart rate slightly decreased during this phase. Three subjects reported mild to moderate headache for various durations within these phases.

Conclusions:

Changes in barometric pressure can be associated with sensations of ear pressure and head compression and may trigger headaches. The generation of these sensations is discussed with regard to convergent trigeminal innervation of the ear, the paranasal sinuses and the cranial meninges.

Micro- and Macroenvironmental Conditions and Stability of Terrestrial Models

Environmental variables can have profound effects on the biological responses of research animals and the outcomes of experiments dependent on them. Some of these influences are both predictable and unpredictable in effect, many are challenging to standardize, and all are influenced by the planning and conduct of experiments and the design and operation of the vivarium. Others are not yet known. Within the immediate environment where the research animal resides, in the vivarium and in transit, the most notable of these factors are ambient temperature, relative humidity, gaseous pollutant by-products of animal metabolism and physiology, dust and particulates, barometric pressure, electromagnetic fields, and illumination. Ambient temperatures in the animal housing environment, in particular those experienced by rodents below the thermoneutral zone, may introduce degrees of stress and thermoregulatory compensative responses that may complicate or invalidate study measurements across a broad array of disciplines. Other factors may have more subtle and specific effects. It is incumbent on scientists designing and executing experiments and staff responsible for animal husbandry to be aware of, understand, measure, systematically record, control, and account for the impact of these factors on sensitive animal model systems to ensure the quality and reproducibility of scientific studies.

A hypothetical proposal for association between migraine and Meniere's disease

Meniere's disease (MD) is a chronic condition affecting the inner ear whose precise etiology is currently unknown. We propose the hypothesis that MD is a migraine-related phenomenon which may have implications for future treatment options for both diseases. The association between MD and migraine is both an epidemiological and a mechanistic one, with up to 51% of individuals with MD experiencing migraine compared to 12% in the general population. The presence of endolymphatic hydrops in those with MD may be the factor that unites the two conditions, as hydropic inner ears have an impaired ability to maintain homeostasis. Migraine headaches are theorized to cause aura and symptoms via spreading cortical depression that ultimately results in substance P release, alterations in blood flow, and neurogenic inflammation. Chronically hydropic inner ears are less able to auto-regulate against the changes induced by active migraine attacks and may ultimately manifest as MD. This same vulnerability to derangements in homeostasis may also explain the common triggering factors of both MD attacks and migraine headaches, including stress, weather, and diet. Similarly, it may explain the efficacy of common treatments for both diseases: current migraine treatments such as anti-hypertensives and anti-convulsants have shown promise in managing MD. Though the etiology of both MD and migraine is likely multifactorial, further exploration of the association between the two conditions may illuminate how to best manage them in the future. MD is likely a manifestation of cochleovestibular migraine, which occurs as a result of migraine related changes in both the cochlea and vestibule.

Blame it on the weather? The association between pain in fibromyalgia, relative humidity, temperature and barometric pressure

Self-reported pain levels in patients with fibromyalgia may change according to weather conditions. Previous studies suggest that low barometric pressure (BMP) is significantly related to increased pain, but that the contribution of changes in BMP has limited clinical relevance. The present study examined whether BMP influenced variability in perceived stress, and if stress levels moderated or mediated the relationship between BMP and pain. Forty-eight patients with fibromyalgia enrolled in a randomized controlled trail (RCT) reported pain and emotional state three times daily with mobile phone messages for a 30-consecutive day period prior to the start of the treatment in the RCT. The patients were unaware that weather data were collected simultaneously with pain and emotional reports. The results showed that lower BMP and increased humidity were significantly associated with increased pain intensity and pain unpleasantness, but only BMP was associated with stress levels. Stress levels moderated the impact of lower BMP on pain intensity significantly, where higher stress was associated with higher pain. Significant individual differences were present shown by a sub-group of patients (n = 8) who reacted opposite compared to the majority of patients (n = 40) with increased pain reports to an increase in BMP. In sum, lower BMP was associated with increased pain and stress levels in the majority of the patients, and stress moderated the relationship between BMP and pain at the group-level. Significant individual differences in response to changes in BMP were present, and the relation between weather and pain may be of clinical relevance at the individual level.

Lowering barometric pressure induces neuronal activation in the superior vestibular nucleus in mice

Weather changes accompanied by decreases in barometric pressure are suggested to trigger meteoropathy, i.e., weather-related pain. We previously reported that neuropathic pain-related behavior in rats is aggravated by lowering barometric pressure, and that this effect is abolished by inner ear lesions. These results suggest that mechanisms that increase vestibular neuronal activity may parallel those that contribute to meteoropathy generation. However, it remains unknown whether changes in barometric pressure activate vestibular neuronal activity. To address this issue, we used expression of c-Fos protein as a marker for neural activation. Male and female mice were placed in a climatic chamber, and the barometric pressure was lowered by 40 hPa, from 1013 hPa, for 50 min (LP stimulation). The total number of c-Fos-positive cells in the vestibular nuclei was counted bilaterally after LP stimulation. We also video-recorded mouse behaviors and calculated the total activity score during the LP stimulation. LP stimulation resulted in significant c-Fos expression in the superior vestibular nucleus (SuVe) of male and female mice. There was no effect of LP stimulation on the total activity score. These data show that distinct neurons in the SuVe respond to LP stimulation. Similar mechanisms may contribute to the generation of meteoropathy in humans.

Seasonal Variation in the Prevalence of Common Orthopaedic Upper Extremity Conditions

Introduction  Seasonal variation in disease processes and injuries have been reported, but it is unclear if this variation exists in upper extremity disorders. The goal of this study is to characterize seasonal and weather variations in common upper extremity orthopaedic conditions. Methods  This cross-sectional study reviewed 68,943 consecutive, new patient visits from January 2010 to September 2015 for carpal tunnel syndrome (CTS), trigger finger (TF), DeQuervain's tenosynovitis (DeQ), lateral epicondylitis (LE), hand arthritis (OA), and distal radius fractures (DRF). Presentation rates for each condition were compared across month, season, and various weather parameters. Results  DRF, OA, and LE had a higher rate of presentation in the winter compared with all other seasons ( p  < 0.001). TF and DeQ showed no statistically significant seasonal differences. Higher barometric pressures were associated with higher rates of all of the diagnoses. Higher humidity was associated with lower rates of CTS, TF, DeQ, LE, and DRF ( p  < 0.001). There was no significant association between temperature levels or amount of precipitation. Discussion  Although the precise mechanism remains unclear, there does appear to be an impact of winter, increased barometric pressure, and higher humidity on presentation rates. Further studies are needed to determine more conclusively why this occurs. Level of Evidence  Level IV, cross-sectional study.

Meteorological factors, air pollutants, and emergency department visits for otitis media: a time series study

AbstractOtitis media (OM) is a very common disease in children, which results in a significant economic burden to the healthcare system for hospital-based outpatient departments, emergency departments (EDs), unscheduled medical examinations, and antibiotic prescriptions. The aim of this retrospective observational study is to investigate the association between climate variables, air pollutants, and OM visits observed in the 2007-2010 period at the ED of Cuneo, Italy. Measures of meteorological parameters (temperature, humidity, atmospheric pressure, wind) and outdoor air pollutants (particulate matter, ozone, nitrous dioxide) were analyzed at two statistical stages and in several specific steps (crude and adjusted models) according to Poisson's regression. Response variables included daily examinations for age groups 0-3, 0-6, and 0-18. Control variables included upper respiratory infections (URI), flu (FLU), and several calendar factors. A statistical procedure was implemented to capture any delayed effects. Results show a moderate association for temperature (T), age 0-3, and 0-6 with P < 0.05, as well as nitrous dioxide (NO₂) with P < 0.005 at age 0-18. Results of subsequent models point out to URI as an important control variable. No statistical association was observed for other pollutants and meteorological variables. The dose-response models (DLNM-final stage) implemented separately on a daily and hourly basis point out to an association between temperature (daily model) and RR 1.44 at age 0-3, CI 1.11-1.88 (lag time 0-1 days) and RR 1.43, CI 1.05-1.94 (lag time 0-3 days). The hourly model confirms a specific dose-response effect for T with RR 1.20, CI 1.04-1.38 (lag time range from 0 to 11 to 0-15 h) and for NO₂ with RR 1.03, CI 1.01-1.05 (lag time range from 0 to 8 to 0-15 h). These results support the hypothesis that the clinical context of URI may be an important risk factor in the onset of OM diagnosed at ED level. The study highlights the relevance of URI as a control variable to be included in the statistical analysis in association with meteorological factors and air pollutants. The study also points out to a moderate association of OM with low temperatures and NO₂, with specific risk factors for this variable early in life. Further studies are needed to confirm these findings, particularly with respect to air pollutants in larger urban environments.

Nature's wrath-The effect of weather on pain following orthopaedic trauma

BACKGROUND

Despite frequent complaints by orthopaedic trauma patients, to our knowledge there is no data regarding weather's effect on pain and function following acute and chronic fracture. The aim of our study was to investigate the influence of daily weather conditions on patient reported pain and functional status.

METHODS

We retrospectively examined prospectively collected data from 2369 separate outpatient visits of patients recovering from operative management of acute tibial plateau fractures, acute distal radius fractures, and chronic fracture nonunions. Pain and functional status were assessed using a visual analogue scale (VAS) and the DASH and SMFA functional indexes. For each visit date, the mean temperature, difference between mean temperature and expected temperature, dew point, mean humidity, amount of rain, amount of snow, and barometric pressure were recorded. Statistical analysis was run to search for associations between weather data and patient reported pain and function.

RESULTS

Low barometric pressure was associated with increased pain across all patient visits (p=0.007) and for patients at 1-year follow-up only (p=0.005). At 1-year follow-up, high temperature (p=0.021) and high humidity (p=0.030) were also associated with increased pain. No significant association was noted between weather data and patient reported functional status at any follow-up interval.

CONCLUSIONS

Patient complaints of weather influencing pain after orthopaedic trauma are valid. While pain in the immediate postoperative period is most likely dominated by incisional and soft tissue injuries, as time progresses barometric pressure, temperature, and humidity impact patient pain levels. Affirming and counseling that pain may vary based on changing weather conditions can help manage patient expectations and improve satisfaction.

The frequency of dental abscesses increases in periods of low barometric pressure

Bioclimatic conditions are thought to have an impact on the frequency of dental abscesses but previous studies have suffered from small patient cohorts, methodological obstacles, and restriction to a single site resulting in limited geographic and meteorological variability. The aim of the present study was to investigate the influence of environmental temperature and barometric pressure on the frequency of dental abscesses. Three maxillofacial and two dental clinics in Vienna retrospectively provided a total of 19,218 patients with dentoalveolar abscesses who were treated by intraoral incision between 1998 and 2011. Daily records from six local meteorological stations were consulted to assess daily meteorological parameters. Univariate and multivariate hurdle count regression models were fitted to estimate the effect of daily average barometric pressure and temperature on registered abscess frequencies. Temporal confounders causing variance of the observed abscess frequencies - such as weekday, business day, and month - were taken into consideration. On days of low barometric pressure a significant rise in dental abscess frequency was observed, even when adjusting for confounders. Environmental temperature, in contrast, did not show any effect. In conclusion, bioclimatic conditions affect health as low barometric pressure increases the number of patients with dental abscesses.

Intracanal molar barometric pressure differentials at simulated altitude conditions - proof of concept study

AIM

To evaluate whether objective data could be obtained regarding internal pressure conditions of a molar tooth with canals prepared but not filled exposed to reduced barometric pressures that could be experienced by aircrew.

METHODOLOGY

The root canals of five mandibular molars were prepared but not filled. Root apices were sealed with a resin-modified glass-ionomer liner and root surfaces sealed with a dental adhesive. The sealed root surfaces were then coated with a polyvinylsiloxane (PVS) adhesive and the teeth inserted into cylinders of PVS impression material to the level of the cervical enamel junction. Barometric pressure transducers were placed in the pulp chambers with the endodontic access sealed with cotton and a provisional restoration. The specimens were then subjected to a manually controlled, atmospheric altitude challenge consisting of a slow ascent and descent to a simulated 25 000 feet above sea level followed by a rapid altitude climb and descent. The real-time difference between intracanal and simulated atmospheric pressures were recorded and correlated (Pearson's, P = 0.05).

RESULTS

No tooth material fractured, and there was no failure of the provisional restorations. Barometric pressures inside the closed prepared molar canals and the ambient atmospheric pressure were found to correlate (r(2)  = 0.97-0.99; P < 0.0001), but pressure equalization lags were observed. However, no differences greater than six pounds per square inch (310 torr) were noted.

CONCLUSION

This pilot study established a protocol that demonstrated that objective data regarding barometric pressures within the prepared canals of molars can be obtained at simulated altitude conditions.

Do weather changes influence pain levels in women with fibromyalgia, and can psychosocial variables moderate these influences?

The aim of this study was to examine the association between fibromyalgia pain and weather, and to investigate whether psychosocial factors influence this relationship. Women with chronic widespread pain/fibromyalgia (N = 50) enrolled in a larger study, were recruited from a 4-week inpatient rehabilitation program in Norway ( 2009-2010), and reported their pain and psychological factors up to three times per day (morning, afternoon, evening) for 5 weeks. These ratings were then related to the official local weather parameters. Barometric pressure recorded simultaneously impacted pain significantly while temperature, relative humidity, and solar flux did not. No psychological variables influenced the weather-pain interaction. No weather parameter predicted change in the subsequent pain measures. The magnitude of the inverse association between pain and barometric pressure was very small, and none of the psychological variables studied influenced the association between pain and barometric pressure. All in all, the evidence for a strong weather-pain association in fibromyalgia seems limited at best.

Associations between weather conditions and clinical symptoms in patients with hip osteoarthritis: a 2-year cohort study

The goal of this study was to assess whether there is an association between ambient weather conditions and patients' clinical symptoms in patients with hip osteoarthritis (OA). The design was a cohort study with a 2-year follow-up and 3-monthly measurements and prospectively collected data on weather variables. The study population consisted of 222 primary care patients with hip OA. Weather variables included temperature, wind speed, total amount of sun hours, precipitation, barometric pressure, and relative humidity. The primary outcomes were severity of hip pain and hip disability as measured with the Western Ontario and McMasters University Osteoarthritis Index (WOMAC) pain and function subscales. Associations between hip pain and hip disability and the weather variables were assessed using crude and multivariate adjusted linear mixed-model analysis for repeated measurements. On the day of questionnaire completion, mean relative humidity was associated with WOMAC pain (estimate 0.1; 95% confidence interval=0.0-0.2; P=.02). Relative humidity contributed < or = 1% to the explained within-patient variance and between-patient variance of the WOMAC pain score. Mean barometric pressure was associated with WOMAC function (estimate 0.1; 95% confidence interval=0.0-0.1; P=.02). Barometric pressure contributed < or = 1% to the explained within-patient variance and between-patient variance of the WOMAC function score. The other weather variables were not associated with the WOMAC pain or function score. Our results support the general opinion of OA patients that barometric pressure and relative humidity influence perceived OA symptoms. However, the contribution of these weather variables (< or = 1%) to the severity of OA symptoms is not considered to be clinically relevant.

Atmospheric pressure and suicide attempts in Helsinki, Finland

The influence of weather on mood and mental health is commonly debated. Furthermore, studies concerning weather and suicidal behavior have given inconsistent results. Our aim was to see if daily weather changes associate with the number of suicide attempts in Finland. All suicide attempts treated in the hospitals in Helsinki, Finland, during two separate periods, 8 years apart, were included. Altogether, 3,945 suicide attempts were compared with daily weather parameters and analyzed with a Poisson regression. We found that daily atmospheric pressure correlated statistically significantly with the number of suicide attempts, and for men the correlation was negative. Taking into account the seasonal normal value during the period 1971-2000, daily temperature, global solar radiation and precipitation did not associate with the number of suicide attempts on a statistically significant level in our study. We concluded that daily atmospheric pressure may have an impact on suicidal behavior, especially on suicide attempts of men by violent methods (P < 0.001), and may explain the clustering of suicide attempts. Men seem to be more vulnerable to attempt suicide under low atmospheric pressure and women under high atmospheric pressure. We show only statistical correlations, which leaves the exact mechanisms of interaction between weather and suicidal behavior open. However, suicidal behavior should be assessed from the point of view of weather in addition to psychiatric and social aspects.