Principal Contact
Abstract:
Multiple Sclerosis (MS) is the most common cause of neurological disability in young adults.It is estimated that more than two million people have MS worldwide. This study aimed to assess the incidence of MSand its associated factors in Shiraz,Southwestern Iran.Data related to the inci-dence of MSwere obtainedfrom the MS center of Shiraz University of Medical Sciences from 2001to2014. The study participants were allresidents of Shiraz. The subjects were diagnosed with MS by neurologists(all newly diagnosed patients from 2001-2014) and were registered in MS cen-ter to receivetreatment.Descriptive statistics andunivariate and multivariate Poisson regression. During the study period, 2637 eligible patients were identified. The highest incidence of MS oc-curred in 2011 and 2012 (17.62, 95%CI: 8.02-38.72 and 16.92, 95%CI: 6.23-45.88per 100,000 respectively). Besides,the female to male ratio was 2.95 and44.71% of the MS patients(1070 cases) were in the 20-30 years’age group. In addition, the mean age of the patients was 30.18±8.86 years. The results showed a significant difference among different age and sex groups regarding the incidence of MS (p=0.01). Moreover, a significant relationship was observed betweeneducation level and incidence of MS (p=0.03).The incidence of MS has increasedin the south of Iran more than other regions.
Key words:Multiple sclerosis, Incidence, Young adults, Iran.
Key words:Multiple sclerosis, Incidence, Young adults, Iran.
Introduction:
Multiple Sclerosis (MS)is a chronic inflammato-ry demyelinating diseaseof the central nervous system1-3 with complex aetiology and still un-known causes, which affects individuals in their productive years.4 Up to now,multiple putative aetiologic factors have been recognized for MS, butthe main etiology of the disease has remaine-dunknown.3
The mean age at onset of MS is 30 years (ranging from 20 to 40 years). In other words,the disease onset typically occurs in young adults, thus leading to long-term physical effects.5 This diseasehas also considerable social impacts and economic consequences.6,7 Individuals with MS can expe-rience high levels of disability and impaired quality of life for prolonged periods.8
MS is recognized worldwide; however, the re-ported incidence and prevalence rates vary con-siderably among regions and populations.9 The observed patterns appear consistent with diffe-rential genetic predispositions and also implicate environmental risk factors that modulate the risk of MS at the population level.10 The highest pre-valence of MS is related to Europe and North America. However, evidence has shown an in-crease in the incidence of this disease in arid regions and developing countries.11 The incidence of MS was 6.96/100,000 in Europe,12 4.28/100,000 in France13 11.2/100,000 in United Kingdom,14 and 9.1/100,000 in all regions of Iran in 2013.11 Several population-based studies have also shown a sharp increase in the prevalence and incidence of MS in Iran.11 Beside, a study in Iran showed thatthe incidence and prevalence of MS have increased rapidly, especially in females, in Iran.11Up to now, some studies have surveyed the incidence and prevalence of MS in Iran; however, this issue has not been investigated in south of the country. Shiraz, located in southwest of Iran, is one of the largest and most populous cities of the country. Nevertheless, no studies have been conducted on the incidence of MS in this area until now. Besides, a study conducted in Iran showed that future research should focus on de-termining the epidemiological features of MS in the neglected provinces, especially in south.11 Overall, it is important to have accurate and up to date information regarding the inci-dence of MS in Iranin order to understand the impact of this disease and to ensure that adequate resources are provided regionally for individuals affected by MS.8
Therefore,the presentstudy aimed to assess thein-cidence of MS in Shiraz from 2001 to 2014.It is important for the health system and community to know about the epidemiological aspects of MS. The study findings will present information about the disease trend, which can be used by health system managers for predicting services and planning for controlling and decreasing the disease incidence in the region.
Multiple Sclerosis (MS)is a chronic inflammato-ry demyelinating diseaseof the central nervous system1-3 with complex aetiology and still un-known causes, which affects individuals in their productive years.4 Up to now,multiple putative aetiologic factors have been recognized for MS, butthe main etiology of the disease has remaine-dunknown.3
The mean age at onset of MS is 30 years (ranging from 20 to 40 years). In other words,the disease onset typically occurs in young adults, thus leading to long-term physical effects.5 This diseasehas also considerable social impacts and economic consequences.6,7 Individuals with MS can expe-rience high levels of disability and impaired quality of life for prolonged periods.8
MS is recognized worldwide; however, the re-ported incidence and prevalence rates vary con-siderably among regions and populations.9 The observed patterns appear consistent with diffe-rential genetic predispositions and also implicate environmental risk factors that modulate the risk of MS at the population level.10 The highest pre-valence of MS is related to Europe and North America. However, evidence has shown an in-crease in the incidence of this disease in arid regions and developing countries.11 The incidence of MS was 6.96/100,000 in Europe,12 4.28/100,000 in France13 11.2/100,000 in United Kingdom,14 and 9.1/100,000 in all regions of Iran in 2013.11 Several population-based studies have also shown a sharp increase in the prevalence and incidence of MS in Iran.11 Beside, a study in Iran showed thatthe incidence and prevalence of MS have increased rapidly, especially in females, in Iran.11Up to now, some studies have surveyed the incidence and prevalence of MS in Iran; however, this issue has not been investigated in south of the country. Shiraz, located in southwest of Iran, is one of the largest and most populous cities of the country. Nevertheless, no studies have been conducted on the incidence of MS in this area until now. Besides, a study conducted in Iran showed that future research should focus on de-termining the epidemiological features of MS in the neglected provinces, especially in south.11 Overall, it is important to have accurate and up to date information regarding the inci-dence of MS in Iranin order to understand the impact of this disease and to ensure that adequate resources are provided regionally for individuals affected by MS.8
Therefore,the presentstudy aimed to assess thein-cidence of MS in Shiraz from 2001 to 2014.It is important for the health system and community to know about the epidemiological aspects of MS. The study findings will present information about the disease trend, which can be used by health system managers for predicting services and planning for controlling and decreasing the disease incidence in the region.
Materials and Methods:
Thedata related to MS patients were obtained from MS monitoring center of Shiraz University of Medical Sciences between 2001 and 2014.The MS monitoring center is the only institution, which delivers services to MS patients in south of Iran. Thus, most probably, all MS patients refer to this center for treatment follow-up. However, few patients may travel to other provinces for treatment.
Shiraz,located in southwest of Iran,isthe fifth most populous city of Iran and the capital of Farsprovince with a population of over two million. This city is the patient referral centrein south of Iran.15 MS registry in Shiraz was run at the beginning of June 1995; therefore, this research included the patients who were diagnosed with MS between January 2001 and December 2014. A total of 2393 patients diagnosed with MS were enrolled in the study.
The inclusion criteria of this study werediagnosi-sof MSby neurologists, registry of residence ad-dress in the patients' records, and access to im-age-supported neurological diagnosis.
In order to calculate the incidence rate of MS in each year, the average population wasobtained-based on the census performed in Iran in 2006 and 2011 (Iran's statistical center). For other years, the average population was estimated by Nt=N0(1+r)t (Nt = population size at time t; No = original population size, r = intrinsic rate of increase, and t = time).16
The data were analyzed using Excel (2013) and Stata-SE (version 11) software programs through descriptive statistics andunivariate and multivariate Poisson regression. The association between each of the explanatory variables, including age, sex, and education level, and incidence rate of MS was determined using univariate and multivariate Poisson regression.Then, the final model of Poisson regression was fitted by all the factors that were statistically significant in the univariate analysis.The findings have been shown as inci-dence rates and 95% confidence intervals (CI95%). Besides, the significance level was set at 0.05.
The research was conducted in accordance with the Helsinki Declaration and it was approved by the Ethics Committeeof Shiraz University of Medical Sciences, Shiraz, Iran.
Thedata related to MS patients were obtained from MS monitoring center of Shiraz University of Medical Sciences between 2001 and 2014.The MS monitoring center is the only institution, which delivers services to MS patients in south of Iran. Thus, most probably, all MS patients refer to this center for treatment follow-up. However, few patients may travel to other provinces for treatment.
Shiraz,located in southwest of Iran,isthe fifth most populous city of Iran and the capital of Farsprovince with a population of over two million. This city is the patient referral centrein south of Iran.15 MS registry in Shiraz was run at the beginning of June 1995; therefore, this research included the patients who were diagnosed with MS between January 2001 and December 2014. A total of 2393 patients diagnosed with MS were enrolled in the study.
The inclusion criteria of this study werediagnosi-sof MSby neurologists, registry of residence ad-dress in the patients' records, and access to im-age-supported neurological diagnosis.
In order to calculate the incidence rate of MS in each year, the average population wasobtained-based on the census performed in Iran in 2006 and 2011 (Iran's statistical center). For other years, the average population was estimated by Nt=N0(1+r)t (Nt = population size at time t; No = original population size, r = intrinsic rate of increase, and t = time).16
The data were analyzed using Excel (2013) and Stata-SE (version 11) software programs through descriptive statistics andunivariate and multivariate Poisson regression. The association between each of the explanatory variables, including age, sex, and education level, and incidence rate of MS was determined using univariate and multivariate Poisson regression.Then, the final model of Poisson regression was fitted by all the factors that were statistically significant in the univariate analysis.The findings have been shown as inci-dence rates and 95% confidence intervals (CI95%). Besides, the significance level was set at 0.05.
The research was conducted in accordance with the Helsinki Declaration and it was approved by the Ethics Committeeof Shiraz University of Medical Sciences, Shiraz, Iran.
Result:
This study was performed on 2393 MS patients with the mean age of 30.18±8.86 years (CI95%: 30.16-30.88). Additionally, the mean age of male and female patients was 30.67±8.89 (CI95%: 30.04-31.64) and 30.05±8.86 years (CI95%: 30.04-30.83), respectively. Also, approximately 78.81% of the MS patients (n=1886) were female.
In all the MS patients, the important drugs pre-scribed based on physicians’ orders were Cinno-vex(n=771, 2.21%), Betaferon (n= 412, 13.67%), Recigen (n= 365, 15.26%), Rebif (n=327, 13.67%), and Avonex (n=296, 12.37%). Also, the lowest number of patients were treated with Zifron (n=18, 0.75%). The mean dose of the drugs used by the patients was 8.81±5.63 dosages per month.
The highest incidence of MS was detected in 2011 (312 cases). Other characteristics of the patients and the relationships between their cha-racteristics and theincidence of MS have been presented.
According totable I, the highestincidence of MSoccurred in the 20-30 years’ age group(1070 cases, 44.71%), while the lowest incidence was detected in the above-50-years age group. More-over, the finding of Poisson regressionshoweda significant difference among the age groups re-garding the incidence of MS(p=0.01). The results also revealed a significant difference between the males and females concerning the incidence of MS (p=0.01). Accordingly, the incidence rate of MS was attained as12.66 and 6.81 per 100,000 in females and males, respectively.
As shown in table I,most of the patients had aca-demic education (46.21%) followed by diploma (26.45%). Besides, the incidence of MS was significantly associatedwitheducation level (p=0.02); the highest incidence of MS (13.15) was related to the patients with academic educa-tion. Also, the most prevalent type of MS was the relapsing-remitting form (12.22).
The incidence rate of MS based on various years under studyhas beenindicated in table II.
The average population was obtainedbased on the census performed in Iran in 2001, 2006 and 2011. For other years, it was estimated by Nt=N0(1+r)t.
According totable II, the highest incidence rate of MS was related to 2011(17.6292per 100,000) and 2012 (16.92per 100,000). On the other hand, the lowest incidence rates were related to 2001-2006. The results showed a significant difference among the incidence rates of MS in the study years (p=0.01).The trend of MSincidence based on sex has been presented in figure 1.
Figure oneshowed the increasing trend of MSin-cidence in Shiraz from 2001 to 2014. Besides, this increasing trend was partly similar in male and female patients. However, theincidence rate of MS was quite higher in women than in men. The association between the explanatory va-riables (age, sex, education level, and year) and incidence of MS using multivariate Poisson re-gression has been shown in table III.
As shown in table III, in the multivariate model, age, sex, education level (academic/under diplo-ma), and year were significantlyassociated with the incidence of MS. However, no significant difference was observed between the patients with diploma and under diploma degrees regard-ing the incidence of MS (p =0.35). In addition, sex was the most important predictor of inci-dence of MS.
Ebrahimi found a negative association between the prevalence of MS and average environment temperature. Accordingly,the prevalence of the disease was lower intheareas with higher annual averagetemperature.21 However, the incidence of MS was higher in Shirazwithhotanddryweather-comparedtonorth of Iran with cold weather. Moreover, Ching-Piao Tsai found that 54.03% of MS patients lived in north of Taiwan.22 Therefore, the results of our study were in contrast to those obtained by Ebrahimi.
In the current study, the female to male ratio was 2.95 and women comprised the majority of the MS patients insouth of Iran. This finding has been confirmed in all the studies conducted in this field. Women accounted for 71% of the incident cases in UK.14 Besides, the crude female to male ratio was 2.26 in Sweden.18
Etemadifar found that the incidence and preva-lence of MS increased rapidly, especially in fe-males, in Iran.11In north of Iran,73.1% of the MS patients were female.7 In another study in Iran, the female tomale ratio was 3.1.21 The ratio was also reported to be 3.3 in Taiwan and Italy 22,17 and 2.2 in Norway.19 Considering such high incidence rates in women, it is suggested to survey the gender-related factors to decrease and prevent MS in Iran. According tothis study findings, female to male ratio has been stable over time. Benjaminsen also confirmed this result and found that the ratio remained unchanged from 1990.19 Other studies have also shown sex ratio stability over time.23,24 However, there has been an increase in this ratio across the world.25,26
The findings of the present study demonstrateda-simultaneous increase in population and MS in-cidence.The results also indicated that the highest incidenceof MS was related to the 20-30 years’ age group. However, a previous study showed thatthe peak incidence of MS occurred at the age of 40 years in women and 45 years in men in UK.14 Additionally,the mean age at MS diagno-sis was 37.9 years in Taiwan.22 Also, the mean age of the patients was 33.4 years in north of Iran.7 This implies that age of MS morbidity has decreased in thetwenty-firstcenturyand this dis-tributional peak has shifted to the age group of 20–24 years.11 Since more than half of Iran’s population are less than 35 years old, MS is a critical disease thatthreatens this age group, es-pecially women.11
The results of the current study showed that most of the patients had academic degrees. This shows that educated women might be more exposed to MS compared to other women. It should be mentioned that 17.4 of the women in Iran have academic degrees.16 However, this variable has been investigated only in few studies. Two studies performed in Irancame to the same results as ours.27,28 However,Riise found a marked and linear inverse relationship between the level of education and the risk of MS in anoil company in Norway.29
According to the finding of the present study, the relapsing-remitting form of MS was detected in most of the patients (59.60%). Another study in north of Iran alsoreportedthe relapsing-remitting form of the disease in 67.7% of the patients.7 Therefore, health workers should pay special attention to this form of the disease and investigate its causes to decrease and prevent MS relapse.
In Shiraz,most of theMS patientsusedCinnovex as the dominant drug. In another study,most of the patients used beta-interferon for a period of at least fouryears.30 Hence,future studies are rec-ommended to investigate the effectiveness of MS drugs in Iran.
Conclusion: The incidence of MS has rapidly risen in south of Iran compared to other regions.This incidence was similar to that reported in many western countries.Moreover, the incidence of MS in women was two folds higher than thatinmen, which is warning for Iran’shealth sys-tem.Therefore, future researches should focus on MS risk factors, especially in women, and strate-gies to decrease the incidenceof the disease. It is also necessary to increase the awareness of health managers and health policymakers about the increasing risk of MS in Iranian population.
Acknowledgement: The authors would like to thank Ms. A. Keivanshekouh at the Research Improvement Center of Shiraz University of Medical Sciences for improving the use of Eng-lish in the manuscript.
Conflicts of interest: The authors declare that they have no conflicts of interest.
This study was performed on 2393 MS patients with the mean age of 30.18±8.86 years (CI95%: 30.16-30.88). Additionally, the mean age of male and female patients was 30.67±8.89 (CI95%: 30.04-31.64) and 30.05±8.86 years (CI95%: 30.04-30.83), respectively. Also, approximately 78.81% of the MS patients (n=1886) were female.
In all the MS patients, the important drugs pre-scribed based on physicians’ orders were Cinno-vex(n=771, 2.21%), Betaferon (n= 412, 13.67%), Recigen (n= 365, 15.26%), Rebif (n=327, 13.67%), and Avonex (n=296, 12.37%). Also, the lowest number of patients were treated with Zifron (n=18, 0.75%). The mean dose of the drugs used by the patients was 8.81±5.63 dosages per month.
The highest incidence of MS was detected in 2011 (312 cases). Other characteristics of the patients and the relationships between their cha-racteristics and theincidence of MS have been presented.
Table I: MS patients’ characteristics and their relationship with the incidence of MS in Shiraz
Variables |
Classification |
Frequency (Percentage) |
Incidence rate (per 100,000) |
CI |
p |
Patients’ age (at the time of diagnosis) |
Lower than 20 |
296(12.37) |
7.25 |
(5.12-7.16) |
0.01 |
20-30 |
1070(44 |
10.25 |
(6.12-12. |
||
30-40 |
695(29.04) |
8.86 |
5.12-10.02 |
||
40-50 |
285(11.91) |
3.39 |
2.22-5.20 |
||
Higher than50 |
47(1.96) |
0.92 |
0.22-1.55 |
||
Sex |
Female |
1886(78. |
12.66 |
9.66-15.69 |
0.01 |
Male |
507(21.19) |
6.81 |
4.58-8.21 |
||
Education level |
Lower than Diploma |
617(27.34) |
6.25 |
4.02-8.36 |
0.03 |
Diploma |
597(26.45) |
9.02 |
6.23-12.09 |
||
Academic |
1043(46. |
13.15 |
9.98-17.65 |
||
MS status |
CIS |
693(29.02) |
9.25 |
6.25-14.58 |
0.02 |
Relapsing-remitting |
1431(59 |
12.22 |
8.58-15.71 |
||
Progressive-relapsing |
112(4.69) |
5.22 |
3.56-7.25 |
||
Primary progressive |
48(2.01) |
1.23 |
0.96-2.09 |
||
Secondary progressive |
104(4.36) |
2.36 |
1.10-3.99 |
According totable I, the highestincidence of MSoccurred in the 20-30 years’ age group(1070 cases, 44.71%), while the lowest incidence was detected in the above-50-years age group. More-over, the finding of Poisson regressionshoweda significant difference among the age groups re-garding the incidence of MS(p=0.01). The results also revealed a significant difference between the males and females concerning the incidence of MS (p=0.01). Accordingly, the incidence rate of MS was attained as12.66 and 6.81 per 100,000 in females and males, respectively.
As shown in table I,most of the patients had aca-demic education (46.21%) followed by diploma (26.45%). Besides, the incidence of MS was significantly associatedwitheducation level (p=0.02); the highest incidence of MS (13.15) was related to the patients with academic educa-tion. Also, the most prevalent type of MS was the relapsing-remitting form (12.22).
The incidence rate of MS based on various years under studyhas beenindicated in table II.
Table II:Incidence rate of MS in Shiraz in various years (2001-2014)
Year |
n |
Population average (Shiraz)* |
Incidence rate (per 100,000) |
CI95% |
2001 |
62(2.59) |
1576688 |
3.93 |
2.06-7.48 |
2002 |
61(2.55) |
1596525 |
3.82 |
1.48-9.83 |
2003 |
78(3.26) |
1616362 |
4.83 |
2.37-9.81 |
2004 |
91(3.80) |
1636199 |
5.56 |
1.18-26.12 |
2005 |
125(5.22) |
1656036 |
7.55 |
1.81-31.42 |
2006 |
106 |
1675873 |
6.33 |
3.54-11.27 |
2007 |
170(7.10) |
1695481 |
10.03 |
3.55-28.34 |
2008 |
221(9.50) |
1715318 |
12.88 |
3.50-47.39 |
2009 |
161(6.73) |
1735387 |
9.28 |
3.87-22.21 |
2010 |
236 |
1749926 |
13.49 |
2.50-72.56 |
2011 |
312 |
1770400 |
17.62 |
8.02-38.72 |
2012 |
303 |
1791114 |
16.92 |
6.23-45.88 |
2013 |
238 |
1812070 |
13.13 |
7.16-24.06 |
2014 |
229 |
1833271 |
12.49 |
4.20-37.10 |
The average population was obtainedbased on the census performed in Iran in 2001, 2006 and 2011. For other years, it was estimated by Nt=N0(1+r)t.
According totable II, the highest incidence rate of MS was related to 2011(17.6292per 100,000) and 2012 (16.92per 100,000). On the other hand, the lowest incidence rates were related to 2001-2006. The results showed a significant difference among the incidence rates of MS in the study years (p=0.01).The trend of MSincidence based on sex has been presented in figure 1.
Figure oneshowed the increasing trend of MSin-cidence in Shiraz from 2001 to 2014. Besides, this increasing trend was partly similar in male and female patients. However, theincidence rate of MS was quite higher in women than in men. The association between the explanatory va-riables (age, sex, education level, and year) and incidence of MS using multivariate Poisson re-gression has been shown in table III.
Table III: Multivariate Poisson regression for the relationship between the explanatory factors and incidence of MS in Shiraz
Variables |
Incidence rate |
SE |
Z |
p-value |
CI95% |
Patients’ age (at the time of diagnosis) |
0.62 |
0.88 |
7.05 |
0.01 |
0.08-0.33 |
Sex (female/male) |
2.95 |
0.95 |
3.37 |
0.01 |
1.57-5.55 |
Education |
1.55 |
0.31 |
2.20 |
0.02 |
1.04-2.31 |
Education |
1.44 |
0.58 |
0.92 |
0.35 |
0.65-3.17 |
Year |
1.07 |
0.11 |
6.71 |
0.01 |
1.05-1.09 |
As shown in table III, in the multivariate model, age, sex, education level (academic/under diplo-ma), and year were significantlyassociated with the incidence of MS. However, no significant difference was observed between the patients with diploma and under diploma degrees regard-ing the incidence of MS (p =0.35). In addition, sex was the most important predictor of inci-dence of MS.
Discussion
Based on the present study results, the incidence rate of MSin Shiraz varied from 3.93 per 100,000in 2001 to 17.62 per 100,000 in 2014.Besides, the highest rateswererelated to 2011 and 2012 (17.62 and 16.92per 100,000, respectively), which werehigher compared toEu-rope (6.96Enrique Alcalde-Cabero1),12 France (4.28),13 United Kingdom (11.2),14 Italy (6.4),17 Sweden (10.2),18 Norway (10.1 in 2009)19, and all regions of Iran (9.1 in 2013).11 Although the incidence of MS decreased in 2014, it was still highercompared to other regions in Iran and others countries.Overa11, the study results showed that MS incidence had in-creased in the last decade, which is critical for Iran’shealth system. The increase in the inci-dence of MS in Shiraz might be due to the in-crease in MSpatients’ referral to this city. One study conducted in the center of Iran (Isfahan) indicated that MS incidence had approximately changed from 9.1 to 9.2 from 2009 to 2011.11 Besides,mortalityhas significantly increased in MS patientscompared to the generalpopula-tion.20Therefore, the incidence of MS is high in Shiraz, which is warning for Iran’shealth system. Thus, health managers should take this disease and its related aspects into account.Ebrahimi found a negative association between the prevalence of MS and average environment temperature. Accordingly,the prevalence of the disease was lower intheareas with higher annual averagetemperature.21 However, the incidence of MS was higher in Shirazwithhotanddryweather-comparedtonorth of Iran with cold weather. Moreover, Ching-Piao Tsai found that 54.03% of MS patients lived in north of Taiwan.22 Therefore, the results of our study were in contrast to those obtained by Ebrahimi.
In the current study, the female to male ratio was 2.95 and women comprised the majority of the MS patients insouth of Iran. This finding has been confirmed in all the studies conducted in this field. Women accounted for 71% of the incident cases in UK.14 Besides, the crude female to male ratio was 2.26 in Sweden.18
Etemadifar found that the incidence and preva-lence of MS increased rapidly, especially in fe-males, in Iran.11In north of Iran,73.1% of the MS patients were female.7 In another study in Iran, the female tomale ratio was 3.1.21 The ratio was also reported to be 3.3 in Taiwan and Italy 22,17 and 2.2 in Norway.19 Considering such high incidence rates in women, it is suggested to survey the gender-related factors to decrease and prevent MS in Iran. According tothis study findings, female to male ratio has been stable over time. Benjaminsen also confirmed this result and found that the ratio remained unchanged from 1990.19 Other studies have also shown sex ratio stability over time.23,24 However, there has been an increase in this ratio across the world.25,26
The findings of the present study demonstrateda-simultaneous increase in population and MS in-cidence.The results also indicated that the highest incidenceof MS was related to the 20-30 years’ age group. However, a previous study showed thatthe peak incidence of MS occurred at the age of 40 years in women and 45 years in men in UK.14 Additionally,the mean age at MS diagno-sis was 37.9 years in Taiwan.22 Also, the mean age of the patients was 33.4 years in north of Iran.7 This implies that age of MS morbidity has decreased in thetwenty-firstcenturyand this dis-tributional peak has shifted to the age group of 20–24 years.11 Since more than half of Iran’s population are less than 35 years old, MS is a critical disease thatthreatens this age group, es-pecially women.11
The results of the current study showed that most of the patients had academic degrees. This shows that educated women might be more exposed to MS compared to other women. It should be mentioned that 17.4 of the women in Iran have academic degrees.16 However, this variable has been investigated only in few studies. Two studies performed in Irancame to the same results as ours.27,28 However,Riise found a marked and linear inverse relationship between the level of education and the risk of MS in anoil company in Norway.29
According to the finding of the present study, the relapsing-remitting form of MS was detected in most of the patients (59.60%). Another study in north of Iran alsoreportedthe relapsing-remitting form of the disease in 67.7% of the patients.7 Therefore, health workers should pay special attention to this form of the disease and investigate its causes to decrease and prevent MS relapse.
In Shiraz,most of theMS patientsusedCinnovex as the dominant drug. In another study,most of the patients used beta-interferon for a period of at least fouryears.30 Hence,future studies are rec-ommended to investigate the effectiveness of MS drugs in Iran.
Conclusion: The incidence of MS has rapidly risen in south of Iran compared to other regions.This incidence was similar to that reported in many western countries.Moreover, the incidence of MS in women was two folds higher than thatinmen, which is warning for Iran’shealth sys-tem.Therefore, future researches should focus on MS risk factors, especially in women, and strate-gies to decrease the incidenceof the disease. It is also necessary to increase the awareness of health managers and health policymakers about the increasing risk of MS in Iranian population.
Acknowledgement: The authors would like to thank Ms. A. Keivanshekouh at the Research Improvement Center of Shiraz University of Medical Sciences for improving the use of Eng-lish in the manuscript.
Conflicts of interest: The authors declare that they have no conflicts of interest.
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- Frohman EM, Racke MK, Raine CS: Multiple scle-rosis – the plaque and its pathogenesis. N Engl J Med .2006; 354: 942–55.
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