Effects of meteorological factors on the onset of Bell's palsy

Association of sudden sensorineural hearing loss with meteorological factors: a time series study in Hefei, China, and a literature review

Air pollution can cause disease and has become a major global environmental problem. It is currently believed that air pollution may be related to the progression of SSNHL. As a rapidly developing city in recent years, Hefei has serious air pollution. In order to explore the correlation between meteorological variables and SSNHL admissions, we conducted this study. This study investigated the short-term associations between SSNHL patients admitted to the hospital and Hefei climatic variables. The daily data on SSNHL-related hospital admissions and meteorological variables containing mean temperature (T-mean; °C), diurnal temperature range (DTR; °C), atmospheric pressure (AP; Hp), and relative humidity (RH; %), from 2014 to 2021 (2558 days), were collected. A time-series analysis integrating distributed lag non-linear models and generalized linear models was used. PubMed, Embase, Cochrane Library, and Web of Science databases were searched. Literature published up to August 2023 was reviewed to explore the potential impact mechanisms of meteorological factors on SSNHL. The mechanisms were determined in detail, focusing on wind speed, air pressure, temperature, humidity, and air pollutants. Using a median of 50.00% as a baseline, the effect of exceedingly low T-mean in the single-day hysteresis effect model began at a lag of 8 days (RR = 1.032, 95% CI: 1.001 ~ 1.064). High DTR affected the admission rate for SSNHL on lag 0 day. The significance of the effect was the greatest on that day (RR = 1.054, 95% CI: 1.007 ~ 1.104) and then gradually decreased. High and exceedingly high RH affected the admission rate SSNHL on lag 0 day, and these effects lasted for 8 and 7 days, respectively. There were significant associations between all grades of AP and SSNHL. This is the first study to assess the effect of meteorological variables on SSNHL-related admissions in China using a time-series approach. Long-term exposures to high DTR, RH values, low T-mean values, and all AP grades enhance the incidence of SSNHL in residents. Limiting exposure to extremes of ambient temperature and humidity may reduce the number of SSNHL-related hospital visits in the region. It is advisable to maintain a suitable living environment temperature and avoid extreme temperature fluctuations and high humidity. During periods of high air pollution, it is recommended to stay indoors and refrain from outdoor exercise.

A Retrospective Review of Seasonal Patterns of Idiopathic Facial Nerve Paralysis in a Tertiary Care Center

Background The objective of this retrospective study was to investigate the seasonal patterns of idiopathic facial nerve paralysis, specifically Bell's palsy, in Riyadh, Saudi Arabia. The study aimed to determine if there is a correlation between cold weather and the incidence of Bell's palsy, as well as to examine the relationship between age, gender, comorbidities, and the development of the disease. Methodology Data were collected from King Abdulaziz Medical City in Riyadh, Saudi Arabia, between 2016 and 2021. Electronic medical records of adult patients diagnosed with idiopathic facial paralysis were reviewed. Patients with facial paralysis caused by known illnesses were excluded. Demographic information, clinical characteristics, and the course of the disease were analyzed using SPSS version 25 (IBM Corp., Armonk, NY, USA). Results The study included 136 Bell's palsy patients, with a mean age of 39.9 years. Males represented 58.1% (79) of the sample, and the right side of the face was more commonly affected in 71 (52.2%) patients. The majority of patients had House-Brackmann grade III (51, 37.5%). The monthly distribution showed a higher number of Bell's palsy cases during the winter months, particularly December, October, and November, but the seasonal distribution did not yield a statistically significant difference in incidence. Conclusions While this study observed a higher incidence of Bell's palsy during the winter months, it did not establish a statistically significant correlation between cold temperatures and the onset of Bell's palsy in Riyadh, Saudi Arabia. Furthermore, the study found that Bell's palsy predominantly affects middle-aged males, and comorbidities did not appear to be significant risk factors for the development of the disease. This research lays the groundwork for future investigations into the relationship between weather and the pathogenesis of Bell's palsy in the region.

Monthly Variation in Bell's Palsy Based on Population Data of Korea

INTRODUCTION

Several studies have reported that the number of patients with Bell's palsy varied significantly by month and season. However, few studies have reported the monthly variation in Bell's palsy based on the whole population. We investigated the monthly variation in Bell's palsy in Korea during a long-term period based on whole population data.

METHODS

This retrospective study used the data of the National Health Insurance Service of Korea, which included the entire Korean population from 2008 to 2020. The monthly incidence of Bell's palsy per 100,000 was evaluated in total and according to sex, age, and residence.

RESULTS

The total average monthly incidence differed significantly by month, with the highest observed in January (9.1 per 100,000) and the lowest in June (7.7 per 100,000) (p < 0.001). The average monthly incidence according to sex, age, and residence also varied significantly by month, with most of the highest values noted in January and the lowest in June.

CONCLUSION

There was significant monthly variation in the incidence of Bell's palsy, with the highest in January during the winter and the lowest in June during the summer, based on whole population data over a long-term period in Korea.

Effect of temperature and air pressure on the incidence of Bell's palsy in Hangzhou: a distributed lag non-linear analysis

The etiology of Bell's palsy (BP) is currently unknown, and the findings from previous studies examining the association between seasonal or meteorological factors and BP have been inconsistent. This research aims to clarify this relationship by analyzing a larger dataset and employing appropriate statistical methods. Data from 5387 patients with BP treated at Zhejiang Provincial Hospital of Traditional Chinese Medicine in Hangzhou, Zhejiang Province, from May 1, 2018, to June 30, 2023, was gathered. We assessed the temporal distribution of meteorological factors and the incidence of BP across seasons and months. A distributed lag non-linear model was used to further investigate the lagged and overall effects of temperature and air pressure on the onset of BP. The temporal distribution of BP incidence revealed the highest average number of cases occurring in December and the lowest in June. A correlation existed between BP episodes and temperature or air pressure. The model revealed a higher relative risk during periods of low temperature and high air pressure, characterized by a time lag effect. This correlation was notably more pronounced in female patients and individuals in the young and middle-aged groups. Our findings suggest that exposure to low temperatures and high air pressure constitute risk factors for BP development.

Sunshine duration and solar radiation contributed to severe Bell's palsy: An 11-year time series analysis based on a distributed lag non-linear model model

Although previous studies have suggested that meteorological factors are associated with Bell's palsy, articles on this topic are rare and the results are inconsistent. We aim to reveal the relationship between exposure to different meteorological factors and the onset of severe Bell's palsy (SBP) with daily data. A case-crossover study based on time-series data was applied, and the minimum risk value of each climatic factor was set as the reference value. We fitted a distributed lag non-linear model (DLNM) which applied quasi-Poisson regression to evaluate the exposure-response association and the lag-response association of meteorological factors on the occurrence of SBP. The mode value and per-decile interval value of each meteorological factor were all included in the analysis. Sensitivity analyses were conducted to test the robustness of results. A total of 863 SBP patients (474 males and 389 females) from 7 hospitals in the Shenzhen Futian District were selected from January 2009 to February 2020. The highest relations effect was tested in the cumulative exposure-response result shown as follows; mean temperature at the minimum value 15.3°C with RR of 10.370 (1.557-69.077) over lag 0 to 13; relative humidity at the 30th value 71% with RR of 8.041 (1.016-63.616) over lag 0 to 14; wind speed at the 90th value 31 (0.1 m/s) with RR of 1.286 (1.038-1.593) over lag 0; mean air pressure at the 30th value 1001.4 (pa) with RR of 9.052 (1.039-78.858) over lag 0 to 5; visibility at the 80th value 26.5 (km) with RR of 1.961 (1.005-1.423) over lag 0 to 2; average total cloud cover at the max value 100 (%) with RR 1.787 (1.014-3.148) over lag 0 to 2; sunshine duration at the 10th value 0.1 (h) with RR of 4.772 (1.018-22.361); daily evaporation shows no relationship in the cumulative result; daily average solar radiation at the minimum value 0 (W/m2) with RR of 5.588 (1.184-26.382). There is a relationship between wind speed and the onset of SBP, while mean air pressure, visibility, and average total cloud cover, especially sunshine duration and solar radiation which showed a strong effect, may be associated with severe clinical symptoms of SBP. Mean temperature and relative humidity may affect the course of SBP.

Seasonal Distribution of Bell's Palsy

Bell's palsy (BP) is the most frequently diagnosed acute partial or complete paralysis of the facial nerve which has an unclear etiology and mostly affects one side of the face. Adverse weather conditions are considered to increase the likelihood of developing BP. The retrospective study included 199 BP patients aged 2-82 years that presented to the Ear, Nose, and Throat (ENT) clinics at Kumluca State Hospital and Serik State Hospital, Antalya, Turkey and received treatment between January 2017 and December 2020. The 199 patients comprised 106 (53.3%) men and 93 (46.7%) women with a mean age of 42.23 ± 12.99 years. The highest incidence of BP was observed in winter (December-February) (35%), followed by fall (23%), summer (22%), and spring (20%) (p < 0.05). Accordingly, the incidence of BP was significantly higher in November, December, January and February compared to other months of the year (p < 0.05). The results indicated that BP shows seasonal variation and its peak incidence is in winter (December-February). Further studies are needed to explain the reasons for seasonal differences in BP.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12070-021-02796-2.

Population-based study and a scoping review for the epidemiology and seasonality in and effect of weather on Bell's palsy

The association between weather-related variables or seasons and the development of Bell’s palsy (BP) is controversial. This study aimed to evaluate the incidence and clinical characteristics of BP and assess the effects of meteorological factors on seasonal and monthly incidence. This retrospective population-based study used data from the Korean Health Insurance claims database (NHICD) from 2010 to 2018, in which annual, seasonal, and monthly incidence rates and age and sex distributions were calculated. A multivariate linear regression and autoregressive integrated moving average (ARIMA) model was used to determine the association between the seasonal and monthly incidence of BP and meteorological factors, including average wind speed, temperature, relative humidity, and atmospheric pressure. We also conducted a scoping review of the literature on epidemiological and seasonality studies of BP in the past 30 years and summarized them in a table for easy comparison with other studies. In this study, the incidence rate of BP increased over 9 years (from 12.86 to 19.92 per 100,000 persons) and was the highest in patients in their 60s (31.6/100,000 persons). The seasonal incidence of BP was the highest in autumn and showed a significant difference compared with spring (coefficient − 0.318, p = 0.003) and summer (coefficient − 0.463, p < 0.001), adjusting the year. In the ARIMA analysis, the autocorrelation of the monthly and seasonal lag in the raw data disappeared after adjustment of the seasonal (or monthly) and longitudinal changes, indicating no additional trends outside the seasonal (or monthly) longitudinal changes. The seasonal and monthly incidence of BP was related to low temperature (p = 0.002), high atmospheric pressure (p = 0.034), and low relative humidity (p < 0.001) in the multivariate linear regression. In contrast, in the ARIMA analysis, after adjusting for seasonality, month, and trends, there were no significant meteorological factors associated with the monthly or seasonal incidence rate. In the past 30 years, 12 studies have reported on the prevalence or incidence of BP, and 14 have reported on the relationship between seasons, weather, and incidence. These results indicate that BP is more common among the elderly, and the incidence of BP is increasing due to an aging society, increased medical accessibility, and lifestyle changes. The data also indicate that the onset of BP is associated with low temperature and humidity; however, in the climate zone with extreme temperature and humidity differences between the coldest and hottest months, it is assumed that the marked decrease in temperature (autumn) has more influence on the outbreak of BP than does the actual cold temperature (winter).

Positive Tests for Lyme Disease and Emergency Department Visits for Bell's Palsy Patients

BACKGROUND

Etiologies for Bell's palsy include herpes viruses and Lyme disease, with highest incidence in the colder and warmer months, respectively. In New Jersey, a Lyme-endemic area, the months with the most Lyme disease (80% of cases) are May through October ("Lyme months").

OBJECTIVE

Our aim was to determine whether positive tests for Lyme disease and visits are greater in the Lyme months than the rest of the year for patients with Bell's palsy in New Jersey emergency departments (EDs).

METHODS

We conducted a retrospective chart review from two New Jersey suburban EDs with consecutive patients from February 1, 2013 to January 31, 2018.We identified patients having Bell's palsy using the emergency physician diagnosis. We tabulated positive Lyme tests and visits for Bell's palsy by month of year. We calculated the ratio of positive tests and visits between the Lyme months and the rest of the year along with 95% confidence intervals (CIs).

RESULTS

There were 442 visits for Bell's palsy, 359 (81%) of these patients were tested for Lyme disease and 57 (16%) of the tests were positive. The Lyme months had 7.1 (95% CI 3.5-14.4) times more positive tests and 1.3 (95% CI 1.1-1.4) times more Bell's palsy visits than the rest of the year. Both measures peaked in July.

CONCLUSIONS

In a Lyme-endemic area, positive Lyme tests and ED visits for Bell's palsy are greatest in the Lyme months, peaking in July. This finding can help guide testing and treatment for patients in the ED with Bell's palsy during various months of the year.

Air pollution by NO2 is associated with the risk of Bell's palsy: A nested case-controlled study

This study investigated the relationship of weather and air pollution with the onset of Bell’s palsy. The Korean Health Insurance Review and Assessment Service-National Sample Cohort (HIRA-NSC) data from 2002 through 2013 were used. The 3,935 Bell’s palsy patients were matched with 15,740 control participants. The meteorological data, including daily mean temperature (°C), daily mean highest temperature (°C), daily mean lowest temperature (°C), daily mean temperature difference (°C), relative humidity (%), spot atmospheric pressure (hPa), sulfur dioxide (SO₂) (ppm), nitrogen dioxide (NO₂) (ppm), ozone (O₃) (ppm), carbon monoxide (CO) (ppm), and PM₁₀ (particulate matter ≤ 10 μg/m³) for 60 days, 30 days, 14 days, 7 days, and 3 days prior to the index date were analyzed for Bell’s palsy cases and controls. Conditional logistic regression analysis was used to estimate the odds ratios (ORs) of the association between the meteorological data and Bell’s palsy. The mean NO₂ and PM₁₀ concentrations for 60 days were higher, while that of O₃ was lower in the Bell’s palsy group than in the control group (both P < 0.001). The Bell’s palsy group showed 16.63-fold higher odds of NO₂ for 60 days (0.1 ppm) than the control group (95% CI = 10.18–27.16, P < 0.001). The ORs of PM₁₀, and O₃ for 60 days showed inconsistent results according to the included variables. Bell’s palsy was related to high concentrations of NO₂.

Immune-related gene expression profiles of hypothermia adipocytes: Implications for Bell's palsy

OBJECTIVE

To identify immune-related gene expression profiles of adipocytes under low temperatures with RNA sequencing as a model for Bell's palsy implications.

METHODS

Adipocytes were harvested from the white adipose tissue of male Sprague-Dawley rats and cultured under different acute-grade cold exposure conditions of 30, 20, and 10°C, and their genomes were sequenced for RNA sequencing analysis. The differentially expressed genes (DEGs) were validated with reverse transcription polymerase chain reaction.

RESULTS

In total, 55 (35 upregulated and 20 downregulated), 121 (76 upregulated and 45 downregulated), and 92 (64 upregulated and 28 downregulated) DEGs were identified under 30, 20, and 10°C compared with the control, respectively. KEGG and GO analysis revealed that the DEGs were considerably enriched in immune-related pathways (leukocyte transendothelial migration and platelet activation) and infection (bacterial invasion of epithelial cells and Salmonella infection). The levels of key inflammatory chemokines (CSF1, CXCL1, CCL2, and CCL7) were enhanced after cold exposure.

CONCLUSION

These findings broaden our understanding of the immune responses to cold exposure in adipocytes. The molecular profiles of adipocyte immune function will help clarify the potential mechanism impacting myelin, which might contribute to the development of strategies to control Bell's palsy.

The etiology of Bell's palsy: a review

Bell’s palsy is the most common condition involving a rapid and unilateral onset of peripheral paresis/paralysis of the seventh cranial nerve. It affects 11.5–53.3 per 100,000 individuals a year across different populations. Bell’s palsy is a health issue causing concern and has an extremely negative effect on both patients and their families. Therefore, diagnosis and prompt cause determination are key for early treatment. However, the etiology of Bell’s palsy is unclear, and this affects its treatment. Thus, it is critical to determine the causes of Bell’s palsy so that targeted treatment approaches can be developed and employed. This article reviews the literature on the diagnosis of Bell’s palsy and examines possible etiologies of the disorder. It also suggests that the diagnosis of idiopathic facial palsy is based on exclusion and is most often made based on five factors including anatomical structure, viral infection, ischemia, inflammation, and cold stimulation responsivity.

Effects of Wind Chill Factor, Temperature and Other Meteorological Parameters on the Incidence of Bell's Palsy: Results Based on a Retrospective, 7-Year Long, Greek Population Study

BACKGROUND

The etiology of Bell's palsy (BP), the most common type of dysfunction of the facial nerve, remains unclear despite vigorous research. Data concerning the effects of meteorological factors (MFs) on its appearance are inconclusive. The aim of our study was to examine the demographics of a convenience sample of patients with BP and to determine the effects of several MFs in the recorded number of cases per month (cpm).

METHODS

We retrospectively reviewed 568 files of BP patients and concomitant data of MFs during an 84-month observation period. Information collected included age, gender, diabetic status, number of cpm (months further categorized as winter or summer), mean daily and monthly temperatures and wind speeds and monthly values of wind chill factor (WCF), a measure dependent on both temperature and wind speed. Potential correlations were estimated by univariate analyses (p = 0.05).

RESULTS

Demographics were in line with previous research regarding age and diabetic status, but indicative of slight male preponderance. Summer months and mean monthly temperatures showed significant negative correlations with cpm (p = 0.002 and <0.000, respectively) and strong positive correlation with WCF (p < 0.000).

CONCLUSIONS

MFs can substantially influence the possibility for BP appearance. We propose WCF as a novel, reliable estimator of the overall MF-derived risk.

Meteorological conditions related to the onset of idiopathic sudden sensorineural hearing loss

PURPOSE

The objective of this study was to evaluate the effect of meteorological factors on the onset of idiopathic sudden sensorineural hearing loss (ISSHL).

MATERIALS AND METHODS

Meteorological data from 2005 to 2011 were obtained from the web-based "Monthly Weather Reports of the Meteorological Administration" database. Patients with ISSHL who visited our hospital during this same period and presented the precise day on which hearing loss developed were included in this retrospective study. Twelve meteorological factors were analyzed between the days when ISSHL onset was observed as well as the days when ISSHL did not occur. The weather conditions occurring 1-7 days before ISSHL onset were also analyzed to assess any possible delayed effects of meteorological factors on the onset of ISSHL.

RESULTS

During the study period, 607 patients were included for the study. Although mean and maximal wind velocities were higher for the days when ISSHL occurred than the days without ISSHL onset, after adjusting the value for multiple comparisons, we cannot find any significant relationship between any of meteorological factors and the onset of ISSHL. However, in analysis of time lag effect of the weather conditions, we found that there was still a significant difference in maximum wind speed on 5 days before ISSHL onset even after applying Bonferroni correction.

CONCLUSION

The result of this study suggests that stronger wind speed may be related to the occurrence of ISSHL.