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Osteoarthritis (OA) is the most common form of arthritis and one of the causes of pain and disability. The hair graying characteristic correlates strictly with chronological aging and take places to varying degrees in all individuals, disregarding gender or race.
Comparison of the degrees of clinical and radiologic severity of the knee OA in individuals with early hair graying compared to ordinary individuals.
A total of 60 patients with knee OA and similar demographic characteristics were enrolled in this study. All patients were classified in to 3 age subgroups in each of the case and control groups (30-40 year, 41-50 year, 51-60 year). In the case group, the patients must had early hair graying, too. Knee OA were classified using the Kellgren-Lawrence (KL) grading scale. Western Ontario McMaster University Osteoarthritis index (WOMAC) was applied to assess clinical severity of the knee OA.
The mean ± SD of WOMAC index in the case group was 60.7 ± 15.9 and in the control group was 55.3 ± 15.3 (P = 0.1). The mean rank of KL scale in case group was 35.3 and in the control group was 25.6 (P = 0.02).
Even at the same age of OA onset, the rate of progression of radiological findings and the grade of joint destruction in individuals with early hair graying are greater than normal individuals. However, clinical and functional relevant remain unclear.
Osteoarthritis (OA) is the most common form of arthritis and one of the causes of pain and disability.[1,2] It is estimated that 27 million of adults in US suffer from OA, more than nine million of whom have symptomatic knee OA. The prevalence of OA is expected to increase as the population ages; it affects women more than men. From an individual standpoint, symptomatic OA is correlated with chronic pain and difficulty in performing the usual daily activities necessary to live independence. From a social standpoint, OA has a high impact on direct and indirect costs in community.
OA risk factors include genetic risk factors, constitutional risk factors such as: Ageing, female sex, obesity; and biomechanical risk factors. Reactive oxygen species (ROS) have been implicated in directly promoting catabolic processes, matrix degradation and chondrocyte apoptosis. The findings of this apoptotic acceleration (promotion of the process of programmed cell death) and premature aging in OA confirm that the disease is age dependent, mechanically driven, and chemically, particularly ROS mediated.
The hair graying characteristic correlates strictly with chronological aging and take places to varying degrees in all individuals, disregarding gender or race. Age of the onset also seems to be hereditary, with onset commonly in the late fourth decade. The average age is mid-30s for whites, late-30s for Asians, and mid-40 s for Africans. There is a traditional 50/50/50 rule of thumb, which states that “at age 50 years, 50% of the population has at least 50% gray hair.” However, in a recent study calculating the percentage of people showing at least 50% gray hair coverage at age 50 years, leads to a global range of 6-23%, according to ethnic, geographical origin and natural hair color that this percentage has been well below that expressed by the ‘50’ rule of thumb.
Hair is said to gray prematurely if graying occurs before the age of 20 in Caucasian, before 25 in Asians and before 30 in Africans. ROS alter Deoxyribonucleic acid (nuclear and mitochondrial), result in the accumulation of mutations, cause oxidative stress and also cause anti-oxidant mechanisms. ROS have been involved in melanocyte damage in mice with BCL-2 (B-cell lymphoma 2) deficiency.
Whether hair graying, early or otherwise, is a risk factor/predictor for diseases is controversial. Previous studies have shown a correlation of early hair graying with osteopenia and coronary artery disease.[7,8,9] Based on our clinical observation, we have a hypothesis indicating that individuals with early hair graying as compared to usual individuals experience greater degrees of OA. The aim of the present study was to compare the degrees of clinical and radiologic severity of the knee OA in individuals with early hair graying compared to ordinary individuals.
Sixty patients aged between 30 and 60 years were recruited from those who referred to our outpatient clinics due to knee pain (from October 2010 to December 2011). This study included patients with knee OA diagnosed using the American College of Rheumatology criteria for OA.
Exclusion criteria were rheumatologic, metabolic, or endocrine disease; obesity (body mass index >30); recurrent trauma to the knee (occupational trauma); previous trauma to the knee; vitiligo; pernicious anemia; congenital anomaly.
In all patients with knee OA who had the inclusion criteria, the age of the onset of hair graying was determined. Furthermore, they were asked “at what age most (>70%) hair graying occurred?.” The patients whose hair graying onset was before the age of 25 year or most (>70%) of hair graying had occurred before the age of 40 years were included in the present study as case group.
Anteroposterior and lateral radiographs of the symptomatic knee were obtained. The radiographs were scored by an experienced radiologist using the Kellgren-Lawrence (KL) grading scale. This scale shows the severity of the knee OA in x-ray and includes five grades (0-4).
The pain level and functional state of each patient were evaluated using Western Ontario McMaster University Osteoarthritis index (WOMAC). WOMAC consists of three subscales: Pain, stiffness, and physical function. A higher score on this index indicates poorer function or greater pain.
The data of study were arranged according to the patient age, KL grade, and WOMAC score related to the patient. The degrees of clinical and radiologic severity of knee OA in individuals with early hair graying compared to ordinary individuals, were analyzed.
The patients were classified into two groups:
Patients in each group were sub-classified in three age groups: 30-40 year, 41-50 year, and 51-60 year. We compared all the subgroups with each other in case and control groups.
For analysis of data, SPSS, version 15 was used. Comparison of the WOMAC score of those with early hair graying with those of control group was made using the Student's t test. Furthermore, comparison of the KL grade of the case group with those of control group was made using the Mann Whiteny U test. P < 0.05 was considered as statistically significant in this study.
A total of 63 patients enrolled in the present study; 33 patients in the case group and 30 in the control group. All the patients were classified into three age subgroups in each of case and control groups as follows [Table 1]. Both case and control groups had the same demographic characteristics.
The age group 30-40 year, due to low sample size in the case group and lack of sample in the control group, we could not analyze their data and this group excluded from our study.
The amount of WOMAC index in two groups was compared and as it has been shown in Table 2 (60.7 ± 15.9 in case group vs. 55.3 ± 15.3 in control group) there was no significant statistical difference between these two groups (P < 0.1). Furthermore, the amount of WOMAC index distribution among each subgroup of case and control patients was also obtained that there were no significant statistical differences between these two subgroups [Table 3].
As illustrated in Table 4, the score of KL scale in two groups (35.3 in case group vs. 25.6 in control group) was compared and the difference between them was significant (P < 0.02). The score of KL scale among each subgroup was also obtained and just in subgroup of 41-50 year the difference between case and control groups (19.2 vs. 11.7) was significant (P < 0.01).
While numerous papers have reported on the biological mechanisms of human hair pigmentation and graying, epidemiological description of graying process and especially the definition of early hair graying remain scarce.
Although there are some arguments, a rule of thumb is that by 50 years, 50% of people have 50% gray hair.[5,10] As previously stated, graying is related to ethnic and geographical origin and indeed, hair is said to gray prematurely only if graying occurs before the age of 20 years in whites, before 25 years in Asians and before 30 years in Africans.[10,11] On the other hands, some authors believe that early hair graying is defined a priori as the majority hair graying(>70%) before age 40 year.
This study compared the clinical and radiologic severity of the patients with knee OA between those with early hair graying and those without it. To the best of our knowledge, no study was found showing this correlation, but similar studies have been carried out on the correlation between early hair graying and other diseases.
A recent study showed that individuals with early hair graying (with no other risk factors) were 4 times more likely to have osteopenia than individuals without hair graying. There was an obvious correlation with familial osteoporosis, too. It may be concluded that early hair graying could account for a small part of the difference in bone mineral density within the population.
Another study reported a lower correlation between early hair graying and early cardiovascular disease, perhaps it should be considered as a risk factor for coronary disease and used to recognize individuals at increased risk.
We compared the clinical severity and radiologic severity of knee OA between the two groups generally and under the breakdown of age group (in three subgroups of age: 30-40 year, 41-50 year, 51-60 year). In the age group 30-40 year, we had 3 patients in the case group with significant knee OA in two of them (KL = 3, KL = 4). In the control group, we had no case in this age group that had the inclusion criteria to be enrolled in study. Therefore, due to the impossibility of statistical analysis between these two groups and the possibility of error, this age group was excluded from the study.
As it showed in Tables Tables22 and and3,3, the amount of WOMAC index in the case group is greater than that in the control group either generally and under the breakdown of age groups. However, the differences are not significant statistically.
As you can see in Table 4, severity of radiographic changes in the case group are significantly greater than that of the control group (P < 0.02). With regard to Table 5, we can conclude that the significant differences are related to the age group 41-50 year. In the age group, 51-60 year, despite the greater KL grade in the case group in comparison to the control group, their differences are not significant statistically.
Based on these preliminary data, we can conclude that even at the same age of OA onset, the rate of progression of OA and the grade of joint destruction in individuals with early hair graying are greater than normal individuals, but this effect on functional status is inconsiderable.
Whether early hair graying correlates definitely with early joint cartilage aging remains unclear. It can be due to the limited study time and small sample size. Furthermore, in this preliminary study, we just evaluated patients referring with clinical OA and early radiological findings in younger asymptomatic individuals with early gray hair should be evaluated in future studies to better determine this basic hypothesis.
The support of this work, which was a thesis for degree of specialty in physical medicine and rehabilitation (Dr. Shima Foruzi, Code No: 2098), is gratefully acknowledged from the Vice-Chancellery of Research and Technology of Shiraz University of Medical Sciences.
Source of Support: The Vice-Chancellery of Research and Technology of Shiraz University of Medical Sciences
Conflict of Interest: None declared.