Effect of seasonal fluctuation of ambient temperature on fatigue in multiple sclerosis patients living in Attica, Greece

Thoughts on Fatigue in Multiple Sclerosis Patients

Chronic fatigue is a common symptom in people with multiple sclerosis (PwMS) and presents as a reversible motor and cognitive impairment with reduced motivation and a desire to rest. The presentation of fatigue symptomatology in PwMS can be spontaneous or induced by mental or physical activity, temperature and humidity fluctuations, acute infections, and even food ingestion. Even though the exacerbation of fatigue symptomatology due to heat reaction is well established, the role of environmental temperature (ambient temperature and relative humidity) is not yet fully understood, and there is not enough systematic evidence regarding its effect. In this article, we present our opinion (based on the current literature and clinical experience) regarding the role of environmental temperature in the manifestation of fatigue symptomatology in PwMS.

The Dimensionality of the Multidimensional Fatigue Inventory (MFI-20) Derived From Healthy Adults and Patient Subpopulations: A Challenge for Clinicians

Introduction: Fatigue is associated with various diseases of different origins extending from immune disorders to cancer. The purpose of this study was to explore the psychometric properties/dimensionality of the Multidimensional Fatigue Inventory (MFI-20) questionnaire in samples of healthy adults and patient subgroups in Greece.

Methods: This was a multicenter cross-sectional study that included 80 women with breast cancer, 108 patients with multiple sclerosis (MS), 100 people with thalassemia diagnosis, and 185 healthy adults, aged 18-45 years. All patients were adults. Patients were recruited from a breast surgery clinic, a neurological clinic, and a thalassemia unit, while healthy adults were recruited from the University of West Attica students and personnel. The MFI-20, the modified fatigue impact scale (MFIS), the fatigue severity scale (FSS), and the Hamilton anxiety-depression scale (HANDS) were used. Internal consistency, repeatability, test-retest reliability, construct, and convergent validity were investigated.

Results: MFI-20 exhibited excellent reliability properties (internal consistency: Cronbach’s alpha MFI-20 subscales ranged from 0.83 to 0.94; repeatability: Pearson’s r = 0.335 [p < 0.001]). Significant correlations were found between MFI-20 and MFIS: Pearson’s r = 0.870, FSS: Pearson’s r = 0.582 - 0.335, and HANDS: Pearson’s r = 0.734 - 0.442 (all p-values < 0.0001) on all subsamples. However, its dimensionality is questionable depending on the subpopulation tested, and the one-dimension perspective is possible. MS patients exhibited the highest total score (55.26 ± 16.53), while thalassemia patients exhibited the lowest score (45.09 ± 13.54). In all subscales, thalassemia patients differed statistically significantly from the MS patients (p < 0.01), while in the reduced activity subscale, thalassemia patients differed significantly from all other groups (p < 0.01).

Conclusions: As strict fatigue subscale classification is questionable, the use of MFI-20 total score is suggested for the assessment of fatigue in clinical populations. As MFI-20 is a very useful research tool for studying fatigue, the use of the total and/or partial scores depends on the clinical population. Total score instead of (or additionally) partial scores is suggested in clinical practice.

The Seasonal Fluctuation of Fatigue in Multiple Sclerosis

Background

Fatigue is a common symptom in patients with multiple sclerosis. Several studies suggest that outdoor temperature can impact fatigue severity, but a systematic study of seasonal variations is lacking.

Methods

Fatigue was assessed with the Fatigue Scale for Motor and Cognitive Functions (FSMC) in a temperate climatic zone with an average outdoor temperature of 8.8°C. This study included 258 patients with multiple sclerosis from 572 visits temporally distributed over the year. The data were adjusted for age, sex, cognition, depression, disease severity, and follow-up time. Linear regression models were performed to determine whether the temporal course of fatigue was time-independent, linearly time dependent, or non-linearly time dependent.

Results

Fatigue was lowest during January (mean FSMC: 49.84) and highest during August (mean FSMC: 53.88). The regression analysis showed the best fit with a model that included months + months2, which was a non-linear time dependency. Mean FSMC per month correlated significantly with the average monthly temperature (ρ = 0.972; p &lt; 0.001).

Conclusion

In multiple sclerosis, fatigue showed a natural temporal fluctuation. Fatigue was higher during summer compared to winter, with a significant relationship of fatigue with outdoor temperature. This finding should be carefully taken into account when clinically monitoring patients over time to not interpret higher or lower scores independent of seasonal aspects.

Heat Exposure and Multiple Sclerosis-A Regional and Temporal Analysis

Multiple sclerosis (MS) is a neurological disorder that progressively distorts the myelination of axons within the central nervous system (CNS). Increased core body temperature or metabolism as a result of exercise are common causes of short-term exacerbations of neurological symptoms in MS. About 60–80% of patients with MS experience a worsening of their symptoms when exposed to heat. In comparison, less data are available on the relationship between ambient meteorological conditions (e.g., temperature and relative humidity (RH)) and fluctuations in such variables in relation to MS symptoms. Thus, this study examined associations between time-lagged exposure to meteorological conditions and risk of a clinic visit due to MS among US veterans between 2010 and 2013. This study leveraged data from the Veterans Affairs (VA) and National Climactic Data Center (NCDC) for the continental US, partitioned into eight climate zones. We used a case crossover design to assess the risk of a MS clinic visit with respect to several meteorological conditions. Location-specific time-lagged daily (ambient) exposure to temperature, RH, and temperature variations (standard deviation (SD) of temperature) were computed (up to 30 days) for each case (i.e., day of MS visit) and control (a randomly assigned date ± 90–270 days prior to visit). Statistical analyses were conducted to examine independent associations between the selected meteorological conditions and risk of MS visits at the national and regional levels. A total of 533,066 patient visits received a MS diagnosis (International Classifications of Diseases (ICD)-9 code = 340). The Northeast (NE) and Upper Midwest (UMW) regions reported the highest frequency of clinic visits due to MS. Clinic visits were 9% more likely to occur in the spring, summer, and fall months (March–October) than in the winter (OR = 1.089; 95% CI = 1.076–1.103; p < 0.01). In the univariate analyses, the SD of temperature, temperature, and temperature–RH interaction were positively associated with an elevated risk of a MS clinic visit, while the RH was negatively associated with the risk for a clinic visit. In multivariate analyses, the strongest association of a MS clinic visit was observed with the SD of the temperature (OR = 1.012; 95% CI 1.008–1.017; p < 0.01). These associations between MS clinic visits and meteorological conditions varied across climate regions, with the strongest associations being observed in the LMW, UMW, DSW, and NE zones. The SD of the temperature was again the strongest associated predictor when examined regionally. Temperature variations and temperature–RH interactions (a proxy of the heat index) showed significant associations with MS clinic visits. These associations varied across climate regions when examined geographically. Our findings have implications for the management of MS in severe or recurrent cases, especially considering the impending changes in the daily temperature variations and intensity of the heatwaves expected with the intensification of global warming.

Exposure to suboptimal ambient temperature during specific gestational periods and adverse outcomes in mice

Exposure to suboptimal ambient temperature during pregnancy has been reported as a potential teratogen of fetal development. However, limited animal evidence is available regarding the impact of extreme temperatures on maternal pregnancy and the subsequent adverse pregnancy outcomes. Our objective in this study is to investigate the relationship between temperature and maternal stress during pregnancy in mice. This study used the Naval Medical Research Institute (NMRI) mice during the second and third pregnant weeks with the gestational day (GD) (GD 6.5-14.5 and GD 14.5-17.5). Mice were exposed to suboptimal ambient temperature (1 °C, 5 °C, 10 °C, 15 °C, 40 °C, 42 °C, 44 °C, 46 °C, and 48 °C for the experimental group and 23 °C for the control group) 1 h per day, 7 days a weekin each trimester. Measurements of placental development (placental weight [PW] and placental diameter [PD]) and fetal growth (fetal weight [FW] and crown-to-rump length [CRL]) between experimental and control groups were compared using analysis of variance (ANOVA). Data on the occurrence of preterm birth (PTB) and abnormalities were also collected. The results showed that exposure to both cold and heat stress in the second and third weeks of pregnancy caused significant decreases in measurements of placental development (PW and PD) and fetal growth (FW and CRL). For all temperature exposures, 15 °C was identified as the optimal temperature in the development of the embryo. Most PTB occurrences were observed in high-temperature stress groups, with the highest PTB number seen in the exposure group at 48 °C, whereas PTB occurred only at 1 °C among cold stress groups. In the selected exposure experiments, an approximate U-shaped relation was observed between temperature and number of abnormality occurrence. The highest percentage of these anomalies occurred at temperatures of 1 °C and 48 °C, while no abnormalities were observed at 15 °C and in the control group. Our findings strengthened the evidence that exposure to suboptimal ambient temperatures may trigger adverse pregnancy outcomes and worsen embryo and fetal development in mice.

Safety and efficacy of amantadine, modafinil, and methylphenidate for fatigue in multiple sclerosis: a randomised, placebo-controlled, crossover, double-blind trial

BACKGROUND

Methylphenidate, modafinil, and amantadine are commonly prescribed medications for alleviating fatigue in multiple sclerosis; however, the evidence supporting their efficacy is sparse and conflicting. Our goal was to compare the efficacy of these three medications with each other and placebo in patients with multiple sclerosis fatigue.

METHODS

In this randomised, placebo-controlled, four-sequence, four-period, crossover, double-blind trial, patients with multiple sclerosis who reported fatigue and had a Modified Fatigue Impact Scale (MFIS) score of more than 33 were recruited at two academic multiple sclerosis centres in the USA. Participants received oral amantadine (up to 100 mg twice daily), modafinil (up to 100 mg twice daily), methylphenidate (up to 10 mg twice daily), or placebo, each given for up to 6 weeks. All patients were intended to receive all four study medications, in turn, in one of four different sequences with 2-week washout periods between medications. A biostatistician prepared a concealed allocation schedule, stratified by site, randomly assigning a sequence of medications in approximately a 1:1:1:1 ratio, in blocks of eight, to a consecutive series of numbers. The statistician and pharmacists had no role in assessing the participants or collecting data, and the participants, caregivers, and assessors were masked to allocation. The primary outcome measure was the MFIS measured while taking the highest tolerated dose at week 5 of each medication period, analysed by use of a linear mixed-effect regression model. This trial is registered with ClinicalTrials.gov, NCT03185065 and is closed.

FINDINGS

Between Oct 4, 2017, and Feb 27, 2019, of 169 patients screened, 141 patients were enrolled and randomly assigned to one of four medication administration sequences: 35 (25%) patients to the amantadine, placebo, modafinil, and methylphenidate sequence; 34 (24%) patients to the placebo, methylphenidate, amantadine, and modafinil sequence; 35 (25%) patients to the modafinil, amantadine, methylphenidate, and placebo sequence; and 37 (26%) patients to the methylphenidate, modafinil, placebo, and amantadine sequence. Data from 136 participants were available for the intention-to-treat analysis of the primary outcome. The estimated mean values of MFIS total scores at baseline and the maximal tolerated dose were as follows: 51·3 (95% CI 49·0-53·6) at baseline, 40·6 (38·2-43·1) with placebo, 41·3 (38·8-43·7) with amantadine, 39·0 (36·6-41·4) with modafinil, and 38·6 (36·2-41·0) with methylphenidate (p=0·20 for the overall medication effect in the linear mixed-effect regression model). As compared with placebo (38 [31%] of 124 patients), higher proportions of participants reported adverse events while taking amantadine (49 [39%] of 127 patients), modafinil (50 [40%] of 125 patients), and methylphenidate (51 [40%] of 129 patients). Three serious adverse events occurred during the study (pulmonary embolism and myocarditis while taking amantadine, and a multiple sclerosis exacerbation requiring hospital admission while taking modafinil).

INTERPRETATION

Amantadine, modafinil, and methylphenidate were not superior to placebo in improving multiple sclerosis fatigue and caused more frequent adverse events. The results of this study do not support an indiscriminate use of amantadine, modafinil, or methylphenidate for the treatment of fatigue in multiple sclerosis.

FUNDING

Patient-Centered Outcomes Research Institute.

Association between temperature and maternal stress during pregnancy

BACKGROUND

Maternal psychological stress during pregnancy has essentially been conceptualized as a teratogen. However, little is known about the effect of temperature on maternal stress during pregnancy. The aim of this study is to investigate the relationship between temperature and maternal stress during pregnancy.

METHODS

In 2010, a total of 1931 eligible pregnant women were enrolled across Shanghai from four prenatal-care clinics during their mid-to-late pregnancy. Maternal life-event stress and emotional stress levels during pregnancy were assessed by the "Life Event Scale for Pregnant Women" (LESPW) and "Symptom Checklist-90-Revised Scale" (SCL-90-R), respectively. Exposure to ambient temperature was evaluated based on daily regional average in different moving average and lag days. The generalized estimating equations were used to evaluate the relationship between daily average temperature/temperature difference and maternal stress.

RESULTS

After adjusting for relevant confounders, an U-shaped relationship was observed between daily average temperature and maternal Global-Severity-Index (GSI) of the SCL-90-R. Cumulative exposures to extremely low temperatures (< P5, 1.4-10.5℃, lag 0-1 days, 0-2 days and 0-5 days) and extremely high temperatures (≥ P95, 31.2-34.1℃, lag 0-1 days and 0-2 days), and acute exposures to extremely low (lag day 0, 1, 2 and 3) and high (lag day 0, 1) temperatures, all induced higher risks of high GSI (the highest tertile), compared to the risk induced by exposed to an optimal temperature range (20-25℃) (P< 0.05). Increased temperature difference was associated with high maternal GSI (P< 0.05). However, non-significant associations were observed between daily average temperatures/temperature differences and maternal log-transferred LESPW scores.

CONCLUSIONS

Cumulative and acute exposures to extremely low/high temperatures may both induce emotional stress during pregnancy.

No relevant impact of ambient temperature on disability measurements in a large cohort of patients with multiple sclerosis

BACKGROUND AND PURPOSE

Many patients with multiple sclerosis (MS) report a worsening of symptoms due to high ambient temperatures, but objective data about this association are rare and contradictory. The aim of this study was to investigate the influence of ambient temperature on standard clinical tests.

METHODS

We extracted the Symbol Digit Modality Test, Nine Hole Peg Test, Timed 25 Foot Walk (T25FW), Timed Tandem Walk, Expanded Disability Status Scale (EDSS) and quality-of-life items on cognition, fatigue and depression from our clinical database and matched them to historical temperatures. We used linear mixed-effect models to investigate the association between temperature and outcomes.

RESULTS

A total of 1254 patients with MS (mean age, 42.7 years; 69.9% females; 52.1% relapsing-remitting MS, mean EDSS, 3.8) had 5751 assessments between 1996 and 2012. We observed a worsening in the T25FW with higher ambient temperatures in moderately disabled patients (EDSS ≥ 4) but not in less disabled patients. However, an increase of 10°C prolonged the T25FW by just 0.4 s. Other outcomes were not associated with ambient temperatures.

CONCLUSIONS

Higher ambient temperature might compromise walking capabilities in patients with MS with a manifest walking impairment. However, effects are small and not detectable in mildly disabled patients. Hand function, cognition, mood and fatigue do not appear to be correlated with ambient temperature.

1-year course of fatigue in patients on chronic hemodialysis

PURPOSE

Fatigue is common in end-stage renal disease patients receiving hemodialysis, reduces significantly their quality of life and is associated with all-cause and cardiac-related mortality. Unfortunately, little is known about the course of fatigue in patients on chronic hemodialysis.

METHODS

The Vitality Subscale of the SF-36 (SF-36 VS), Short-Form Health Survey, was administered to 45 patients in January (T1), June (T2) and November (T3) 2015.

RESULTS

The score of the SF-36 VS did not differ significantly among T1, T2 and T3. Similarly, the 1-year course of the SF-36 Vitality Subscale score did not differ significantly among T1, T2 and T3 after stratification of patients for sex, age, BMI, IADL and Charlson. Between T1 and T2, 21 out of 45 patients (46.6%) changed their fatigue status: 8 fatigued patients became not-fatigued and 13 not-fatigued patients became fatigued. Between T2 and T3, 12 out of 45 (26.6%) patients changed their fatigue status: 5 fatigued patients became not-fatigued and 7 not-fatigued patients became fatigued. Between T1 and T3, 19 out of 45 patients (42.2%) changed their fatigue status: 6 fatigued patients became not-fatigued and 13 not-fatigued became fatigued.

CONCLUSION

The present study is the first to identify variations in fatigue status among patients on chronic hemodialysis during 1-year course. These findings suggest to frequently assess the presence and severity of fatigue in patients on chronic hemodialysis.