Epidemiologic associations of carpal tunnel syndrome and sleep position: Is there a case for causation?
BACKGROUND
Carpal tunnel syndrome (CTS) is thought to be due to compression of the median nerve in the carpal tunnel. It is known that carpal tunnel pressures are elevated in wrist postures of flexion and extension and in those patients with CTS. Classic symptoms of CTS include night waking with pain, tingling, and numbness. These classic symptoms stimulated our interest in the relationship of sleep to the development of CTS.


METHODS
We reviewed the literature surrounding the epidemiology of CTS and the literature regarding sleep disturbances. Through careful distillation of these studies and a process of reasoning, we have developed a hypothesis for a causal mechanism of CTS.


RESULTS
Epidemiologically, it has been shown that CTS is associated with age, gender, increased body mass index (BMI), diabetes, pregnancy, and is more common in some populations. The same associations noted above for CTS are strongly associated with sleep disturbances. Sleep disturbances due to age, gender, BMI, pregnancy, and population variations are all associated with sleeping in the lateral position supporting the hypothesis that a common causative mechanism of CTS is sleeping in a lateral position.


CONCLUSIONS
We believe that the epidemiologic associations with CTS act through a common causative mechanism, increased sleeping in the lateral position which puts the wrist at increased risk of flexion or extension, compressing the median nerve in the carpal tunnel. This hypothesis is simple and explains the connection between a previously unconnected group of epidemiologic associations. This realization has real clinical significance in that it focuses our attention on the early disorder when it is completely reversible. It clarifies previously confused clinical circumstances, creates research questions that can be tested, and it invites us to change our clinical perspective in this most common form of nerve compression.
McCabe
Steven J
SJ
Department of Bioinformatics and Biostatistics, School of Public Health and Information Sciences, The University of Louisville, 555 South Floyd Street, Suite 400, Louisville, KY, 40202, USA. Steven.mccabe@louisville.edu
Uebele
Anna L
AL
Pihur
Vasyl
V
Rosales
Roberto S
RS
Atroshi
Isam
I
Am J Ind Med. 2002 May;41(5):343-52
12071488
Muscle Nerve. 2005 Oct;32(4):527-32
16025527
Psychiatry Clin Neurosci. 2000 Jun;54(3):340-1
11186104
Holist Nurs Pract. 2003 Jul-Aug;17(4):193-200
12889547
Clin Orthop Relat Res. 2005 Jul;(436):251-60
15995449
Sleep Med. 2001 Sep;2(5):417-22
14592391
Hand Clin. 1993 May;9(2):253-61
8509465
J Bone Joint Surg Am. 1966 Mar;48(2):211-28
5934271
J Occup Environ Med. 2002 Apr;44(4):303-4
11977412
Sleep. 1996 Sep;19(7):531-8
8899931
Neurology. 2002 Jan 22;58(2):289-94
11805259
Arch Phys Med Rehabil. 2005 Apr;86(4):609-18
15827908
Diabet Med. 2005 May;22(5):625-30
15842519
Arthritis Rheum. 2005 Dec 15;53(6):911-9
16342098
Am J Public Health. 2005;95 Suppl 1:S144-50
16030331
Diabetes Res Clin Pract. 1994 Apr;23(3):183-6
7924879
Chest. 1987 Apr;91(4):540-6
3829746
J Psychiatr Res. 2005 Mar;39(2):151-9
15589563
Lakartidningen. 2002 Jan 17;99(3):154-7
11838069
J Rheumatol. 2006 Apr;33(4):796-802
16511937
Ann Intern Med. 1990 Mar 1;112(5):321-7
2306060
Occup Med (Lond). 2003 Mar;53(2):89-94
12637592
Chest. 2000 Oct;118(4):1018-24
11035672
J Hand Surg Am. 1998 Jul;23(4):692-6
9708385
Sleep. 2005 Mar;28(3):309-14
16173651
Clin Cornerstone. 2003;5(3):5-15
14626537
Clin Neuropharmacol. 1985;8 Suppl 1:S49-54
3837686
JAMA. 2006 Apr 5;295(13):1549-55
16595758
Arch Intern Med. 2005 Apr 25;165(8):863-7
15851636
Am J Psychiatry. 1979 Oct;136(10):1257-62
314756
Occup Environ Med. 1997 Oct;54(10):734-40
9404321
J Rheumatol. 2002 Jan;29(1):169-73
11824956
Am J Epidemiol. 2004 Sep 15;160(6):521-30
15353412
JAMA. 1999 Jul 14;282(2):153-8
10411196
J Hand Surg Br. 1994 Feb;19(1):30-4
8169474
JAMA. 2002 Sep 11;288(10):1245-51
12215131
Neurol Sci. 2004 Jun;25(2):48-52
15221621
Diabetes Res Clin Pract. 1991 Aug;13(1-2):45-51
1773713
Arch Phys Med Rehabil. 1998 Oct;79(10):1285-7
9779685
J Bone Joint Surg Am. 1995 Nov;77(11):1695-9
7593079
Clin Neurophysiol. 2001 Oct;112(10):1946-51
11595156
Chest. 1997 Sep;112(3):629-39
9315794
Clin Neurophysiol. 2002 Sep;113(9):1429-34
12169324
J Pak Med Assoc. 2006 Feb;56(2):50-3
16555633
Nephron. 2002 Sep;92(1):127-32
12187095
Occup Med (Lond). 2003 Mar;53(2):83-8
12637591
Am J Epidemiol. 2002 Mar 1;155(5):387-93
11867347
J Abnorm Psychol. 1992 Aug;101(3):514-20
1500608
J Neurol Neurosurg Psychiatry. 2003 Dec;74(12):1674-9
14638888
J Sleep Res. 2002 Jun;11(2):169-77
12028482
Clin Neurol Neurosurg. 2004 Sep;106(4):294-9
15297003
Am J Epidemiol. 2000 Mar 15;151(6):566-74
10733038
Ind Health. 2005 Jan;43(1):11-9
15732298