By Greg Arnold, DC, CSCS, May 28, 2010, abstracted from “Association between Residences in U.S. Northern Latitudes and Rheumatoid Arthritis: A Spatial Analysis of the Nurses’ Health Study” printed online in Environmental Health Perspectives
Rheumatoid arthritis affects 1.3 million Americans (1) and is characterized by joint pain, stiffness, morning stiffness that may last hours, red and puffy hands, fatigue, and weight loss (2). While rheumatoid arthritis costs our healthcare system $11,404 per patient per year, there are also added costs of cardiovascular disease and depression caused by rheumatoid arthritis, increasing the costs to $14,145 and $12,225 per patient, respectively (3).
Supplements like fish oil (4) can help with joint health in patients with rheumatoid arthritis. Now a new study (5) has found that a deficiency in vitamin D, already found to carry long-term disease risks (6), affect pregnancy health (7), is a “major risk factor” for cardiovascular disease (8), and is still very common in U.S. children (9), may also affect joint health in rheumatic patients.
In the study, researchers looked at 461 rheumatic patients and compared them to 9, 220 patients without rheumatoid arthritis who were followed from 1988 to 2002 in the Nurse’s Health Study (10). The patients completed a questionnaire every two years (11) regarding their current location of residence and behavioral risk factors, but not diet. They found “a statistically significant area” in the upper northeast including Vermont, New Hampshire, and southern Maine they identified as “having consistently elevated RA risk” relative to the whole study area. The rates of RA in patients started to decrease significantly in the Northeast once they lived in latitudes corresponding to Pennsylvania, indicating greater sun exposure with decreasing latitude.
These results showing decreased sun exposure (and reduced vitamin D intake) to be supported by earlier research which showed that living in northern latitudes increases risks for other autoimmune conditions like multiple sclerosis (12) and Crohn’s disease (13).
Unfortunately, the researchers did not discuss possible mechanisms for vitamin D’s role in RA nor did they give any recommendations for sun exposure or vitamin D intake. Regardless, they concluded that "women living in higher latitudes may be at greater risk for RA". Prior residence locations may also be a factor in increased RA risk.
Although a universal level has not yet been established, most experts define vitamin D deficiency as blood levels below 20 nanograms per milliliter, vitamin D insufficiency as 21-29 ng/ml, and optimal concentration of at least 30 ng/ml (14). The average U.S. adult consumes about 230 IU vitamin D per day (15) and current recommendations by the National Institutes of Health are 200 IU daily for individuals younger than 50 years, 400 IU daily for individuals between age 50 and 70 years, and 600 IU for those older than age 70 years (16) even though the FDA states that up to 10,000 IU per day is considered safe (17).
Greg Arnold is a Chiropractic Physician practicing in Danville, CA. You can contact Dr. Arnold directly by emailing him at PitchingDoc@msn.com or visiting his web site at www.PitchingDoc.com
1. “Arthritis Related Statistics” - www.cdc.gov/arthritis/data_statistics/arthritis_related_stats.htm
2. “Rhematoid Arthritis” - www.mayoclinic.com/health/rheumatoid-arthritis/ds00020/dsection=symptoms
3. Joyce AT. Hidden cost of rheumatoid arthritis (RA): estimating cost of comorbid cardiovascular disease and depression among patients with RA. J Rheumatol 2009 Apr;36(4):743-52. Epub 2009 Feb 17
5. Vieira et al. Association between Residences in U.S. Northern Latitudes and Rheumatoid Arthritis: A Spatial Analysis of the Nurses’ Health Study. Environmental Health Perspectives, 2010; DOI: 10.1289/ehp.0901861
6. Wagner CL. Does Vitamin D Make the World Go ‘Round’? Breastfeeding Medicine. December 2008, 3(4): 239-250
7. Bodnar LM. Maternal Vitamin D Deficiency Is Associated with Bacterial Vaginosis in the First Trimester of Pregnancy. J. Nutr. 2009 139: 1157-1161. First published online June 1, 2009; doi:10.3945/jn.108.103168
8. Lee JH. .Vitamin D deficiency an important, common, and easily treatable cardiovascular risk factor? J Am Coll Cardiol 2008;52(24):1949-56
9. Mansbach JM. Serum 25-Hydroxyvitamin D Levels Among US Children Aged 1 to 11 Years: Do Children Need More Vitamin D? Pediatrics 2009;124;1404-1410
10. Nurse’s Health Study - http://www.channing.harvard.edu/nhs/
11. Stampfer MJ. Primary prevention of coronary heart disease in women through diet and lifestyle. N Eng J Med 2000;343(1):16-22.
12. Sioka C. Multiple sclerosis, osteoporosis, and vitamin D. J Neurol Sci 2009; 287(1-2):1-6
13. Armitage EL. Incidence of juvenile-onset Crohn’s disease in Scotland: association with northern latitude and affluence. Gastroenterology 2004;127:1051-1057.
14. Bischoff-Ferrari HA, Giovannucci E, Willett WC, Dietrich T, Dawson-Hughes B. Estimation of optimal serum concentrations of 25-hydroxyvitamin D for multiple health outcomes. Am J Clin Nutr 2006;84:18 –28.
15. Moore C, Murphy MM, Keast DR, Holick MF. Vitamin D intake in the United States. J Am Diet Assoc 2004;104:980 –3
16. Dietary Supplement Fact Sheet: Vitamin D. Office of Dietary Supplements, NIH Clinical Center, National Institutes of Health. 2007. Available at: http://dietary-supplements.info.nih.gov/factsheets/vitamind.asp
17. Hathcock JN, Shao A, Vieth R, Heaney R. Risk assessment for vitamin D. Am J Clin Nutr 2007;85:6 –18.