Abstract
Objective
To investigate the effect of vitamin D deficiency on the laryngopharyngeal tract.
Study design
Prospective cohort study.
Setting
Tertiary care center.
Subjects and methods
A total of 38 human subjects were prospectively recruited, equally divided into two groups. The Vitamin D deficiency group defined as 25-OH < 25 ng/dl and the control subjects with normal vitamin D level defined as 25-OH > 25 ng/dl. The presence and severity of vocal tract symptoms was assessed using the Vocal Tract Discomfort score.
Results
There was no significant difference in vocal tract discomfort score for frequency and severity between patients with Vitamin D deficiency and patients with no vitamin D deficiency ( p value 0.272). However there was a significant difference in the mean frequency of burning, aching, soreness and lump sensation ( p value < 0.05) in patients with vitamin D deficiency compared to those with no vitamin D deficiency. There was also a significant difference in the means of vocal tract severity symptoms, namely for burning and aching between patients with vitamin D deficiency compared to patients with no vitamin D deficiency ( p value < 0.05).
Conclusion
Subjects with vitamin D deficiency do not have a higher vocal tract discomfort score than subjects with no vitamin D deficiency. However the frequency and severity of certain vocal tract discomfort symptoms was higher and can be based hypothetically on the similarity in structure between the laryngopharyngeal complex and the musculoskeletal system.
1
Introduction
More than 20.000 articles have appeared in the medical database correlating vitamin D deficiency with adverse health problems, increased morbidity and mortality across all ages . It has been associated with congestive heart failure and elevated blood levels of inflammatory factors, including C-reactive protein and interleukin-10. The risk for multiple sclerosis has been shown to decrease by 41% for every increase of 20 ng per milliliter in 25-hydroxyvitamin D above 24 ng per milliliter . Vitamin D has also been shown to affect the brain with the presence of a link between an increased incidence of schizophrenia and depression in patients with vitamin D deficiency . Hypovitaminosis D has equally been shown to have an effect on rheumatoid arthritis and osteoarthritis and has been incriminated in reducing cellular proliferation of normal cells and cancerous cells. As such it has been linked to numerous health conditions that include arthritis, diabetes, mental disorders, cognitive behavior, multiple sclerosis, cardiovascular diseases, cancer and last but not least diseases of the musculoskeletal system.
Of interest to the authors is the effect of Vitamin D deficiency on bones and muscles. Numerous observations have led researchers to believe there is an association between Vitamin D levels and muscle function. Indeed, the most important one came from studying populations of children with rickets and adults with osteomalacia . It was found that they all suffered from a myopathy typically characterized by proximal muscle weakness, hypotonia and generalized muscular pain that manifested itself as waddling gait, difficulty climbing stairs and standing up . Glerup et al. suggested that only a prolonged vitamin D deficiency can lead to muscle weakness in the general population. Visser et al. demonstrated that patients with Vitamin D deficiency were more likely to report weakness of grip strength . Similarly, the OPRA study showed an association between Vitamin D levels and thigh strength, Romberg balance test and gait speed . When present, the musculoskeletal symptoms in patients with vitamin D deficiency can be attributed either to the condition termed osteomalacic myopathy characterized by skeletal mineralization defect secondary to low vitamin D or to another entity referred to as Hypovitaminosis D myopathy without the presence of osteomalacic bone involvement. This constellation of symptoms has been attributed to morphological changes at a cellular level, namely a decrease in muscle fiber diameter and in the number of vitamin D receptor. These changes have been reported in the muscles of the lower extremities. At the level of the muscle itself, this vitamin D-deficient muscular impairment is translated into delayed muscle relaxation, and longer times to reach peak muscle contraction . Gilsanz et al. demonstrated fat infiltration in the muscles of 90 asymptomatic females with low levels of Vitamin D . Similarly much earlier reports have demonstrated that patients with osteomalacia-related muscle weakness had electromyographic changes compared to healthy controls. Those changes were reversible once Vitamin D levels were corrected .
The high prevalence of hypovitaminosis D and its impact on the musculoskeletal system have intrigued the authors of this manuscript to explore the effects of vitamin D deficiency on the laryngo-pharynegal complex using a validated questionnaire. Given the similarity of the anatomical structures of the laryngopharyngeal complex to the musculoskeletal system in the body, the hypothesis is that patients with vitamin D deficiency have more frequent and more severe vocal tract discomfort symptoms than subjects with normal vitamin D level.
2
Subjects and methods
A total of 38 subjects, 19 with vitamin D deficiency (25-OH < 25 ng/dl) and 19 subjects with normal vitamin D level (25-OH > 25 ng/dl) were recruited for this study after having read the informed consent approved by the Institution Review Board. All subjects underwent fiberoptic or telescopic laryngeal examination prior to their enrollment in this study. Patients with recent history of laryngeal manipulation, respiratory tract infection and/or abnormal laryngeal examination were excluded.
The participants’ severity and frequency of vocal tract discomfort symptoms were subjectively assessed using the Vocal Tract Discomfort scale first described by Woznicka et al. It is a questionnaire that assesses both the severity and frequency of 8 commonly encountered vocal tract symptoms (lump sensation, burning, itching, tight, dry, aching, sore, irritable) using a 0–6 Likert scale for each. The total score ranges between 0 and 48 for each of the severity and frequency of the 8 symptoms. A higher score is translated into more severe and more frequent symptoms .
Descriptive statistics were used to compute the means and the standard deviation of the continuous variables and the frequencies of the categorical variables. Mann-Whitney U test was used to compare the means of the continuous variables between patients and controls. As for the categorical variables, Pearson’s Chi square was used to compute the p value for the categorical variables and Fisher exact test was reported when more than 20% of the cells has a cell count < 5. For the Vocal tract discomfort scale, the four categories that describe the frequency and severity of the symptoms (0: never; 1–3: sometimes; 4–5:often) were reduced to two because the last two categories had many zero’s. All statistical analysis was performed using IBM SPSS Statistics for Windows, Version 22. (Armonk, NY: IBM Corp, Released 2013)
2
Subjects and methods
A total of 38 subjects, 19 with vitamin D deficiency (25-OH < 25 ng/dl) and 19 subjects with normal vitamin D level (25-OH > 25 ng/dl) were recruited for this study after having read the informed consent approved by the Institution Review Board. All subjects underwent fiberoptic or telescopic laryngeal examination prior to their enrollment in this study. Patients with recent history of laryngeal manipulation, respiratory tract infection and/or abnormal laryngeal examination were excluded.
The participants’ severity and frequency of vocal tract discomfort symptoms were subjectively assessed using the Vocal Tract Discomfort scale first described by Woznicka et al. It is a questionnaire that assesses both the severity and frequency of 8 commonly encountered vocal tract symptoms (lump sensation, burning, itching, tight, dry, aching, sore, irritable) using a 0–6 Likert scale for each. The total score ranges between 0 and 48 for each of the severity and frequency of the 8 symptoms. A higher score is translated into more severe and more frequent symptoms .
Descriptive statistics were used to compute the means and the standard deviation of the continuous variables and the frequencies of the categorical variables. Mann-Whitney U test was used to compare the means of the continuous variables between patients and controls. As for the categorical variables, Pearson’s Chi square was used to compute the p value for the categorical variables and Fisher exact test was reported when more than 20% of the cells has a cell count < 5. For the Vocal tract discomfort scale, the four categories that describe the frequency and severity of the symptoms (0: never; 1–3: sometimes; 4–5:often) were reduced to two because the last two categories had many zero’s. All statistical analysis was performed using IBM SPSS Statistics for Windows, Version 22. (Armonk, NY: IBM Corp, Released 2013)
3
Results
3.1
Demographics
The mean age of the total group was 47.29 years with a SD of 13.52 years with a range of 20 years to 65 years. Nineteen patients had Vitamin D deficiency and 19 subjects had normal levels of vitamin D. The mean age and range of both groups are listed in Table 1 . Males and females were equally distributed in the two groups: 57.9% Females and 42.1% Males. No statistical difference in age and gender was identified ( p > 0.05). An alpha level of 0.05 for all statistical tests was used.
| All patients ( N = 38) | Patients with vitamin D deficiency ( N = 19) | Patients with normal vitamin D ( N = 19) | p -Value | |
|---|---|---|---|---|
| Means ± SD | ||||
| Age | 47.29 ± 13.52 | 44.32 ± 14.24 | 50.26 ± 12.42 | 0.209 |
| 20–65 | [Range: 23–63] | [Range: 20–65] | ||
| Frequency (percentage) | ||||
| Gender | 1.000 | |||
| Female | 22(57.9%) | 11(57.9%) | 11(57.9%) | |
| Male | 16(42.1%) | 8(42.1%) | 8(42.1%) | |
| Smoking | 16(42.1%) | 6 (31.6%) | 10 (52.6%) | 0.189 |
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