Do you think you have normal Vitamin D levels? The answer might surprise you. Up to 36% of otherwise healthy adults aged 18-29 have a vitamin D deficiency. This is also true in 41% of outpatients age 49 and over. And in hospitalized patients, the numbers are even higher: 56% of inpatients in the US, and 70-100% of hospital patients in Europe. Women are more likely than men to be have a vitamin D deficiency.

Low vitamin D levels were first reported in association with pain several years ago, when rheumatologists found an association with joint pain and low vitamin D in arthritis patients. Since then, further study of vitamin D levels in many diseases has led to an association with a number of other conditions, one of which is migraine.

Sources of Vitamin D

The primary source of vitamin D is that your body makes its own by synthesis in the skin after sun exposure. Darkly pigmented skin acts as a natural sunblock to this process, and can place an individual at increased risk of vitamin D deficiency.

Risk groups for developing vitamin D deficiency include breastfed infants, older adults (50 and older), individuals with limited sun exposure, people with dark skin, people with fat malabsorption, such as Crohn’s disease or celiac disease, and people who are obese. Obesity constitutes a risk factor because it is thought that vitamin D is pooled in body fat. (Vitamin D is a fat-soluble vitamin.) When it is pooled in fat, it is less available to the bloodstream and the other places in your body where it needs to be active.

Dietary sources of vitamin D are somewhat limited, and include fatty fish, such as salmon, tuna, mackerel, and sardines. Other food sources of vitamin D are egg yolks, fortified milk, beef liver, cod liver oil, fortified margarine, and swiss cheese. Some medications can interfere with vitamin D absorption, such as anticonvulsants, steroids, and non-statin cholesterol-reducing medications.

Vitamin D is necessary for the proper absorption of calcium, so it is important for bone good bone health and muscle function.

Vitamin D Deficiency and Pain

Vitamin D deficiency can cause nonspecific muscle weakness and pain. This can result in chronic widespread pain and fatigue, and may result in a misdiagnosis of either fibromyalgia or chronic fatigue syndrome. If you have been diagnosed with either of these, and have not had a vitamin D level checked, talk to your doctor.

Although the evidence is preliminary, there is also some evidence to suggest that adequate vitamin D levels may also protect against certain cancers and possibly, multiple sclerosis. But don’t just start taking supplements without knowing what you’re doing—get your level checked. It is possible to get too much vitamin D. All fat-soluble vitamins can cause toxicity if taken in excess.

references
Gloth FM, Lindsay JM, Zelesnick LB, Greenough WB. Can Vitamin D Deficiency Produce an Unusual Pain Syndrome? [Internet]. Arch Intern Med. 1991 Aug 1;151(8):1662-1664.[cited 2009 Apr 21] Available from: http://archinte.ama-assn.org/cgi/content/abstract/151/8/1662

Atherton K, Berry DJ, Parsons T, Macfarlane GJ, Power C, Hypponen E. Vitamin D and chronic widespread pain in a white middle-aged British population: evidence from a cross-sectional population survey [Internet]. Ann Rheum Dis. 2008 Aug 12;ard.2008.090456.[cited 2009 Apr 21] Available from: http://ard.bmj.com/cgi/content/abstract/ard.2008.090456v

Holick, MH. High Prevalence of Vitamin D Inadequacy and Implications for Health. Mayo Clinic Proceedings [Internet]. 2006 Mar 1; 81(3):353-373.[cited 2009 Apr 21] Available from: http://mayoclinproc.highwire.org/content/81/3/353.full?maxtoshow=&HITS=&hits=&RESULTFORMAT=&fulltext=Vitamin+D+AND+pain&andorexactfulltext=and&searchid=1&FIRSTINDEX=0&resourcetype=HWCIT

Yetley EA. Assessing the vitamin D status of the US population [Internet]. Am J Clin Nutr. 2008 Aug 1;88(2):558S-564.[cited 2009 May 11] Available from: http://www.ajcn.org/cgi/content/abstract/88/2/558S

Obesity has been called the most common disease in America, although technically I believe dental decay holds that distinction.  From the decade of the 1960s to the decade of the 1970s, medical epidemiologists, the folks who study statistics about diseases, found that the number of people with headaches, and especially migraines, was increasing.  But they didn’t know why.

Now, it may partly be due to increased stress in our lives.  And it may partly be that migraines are being diagnosed more.  However, the increasing waistlines of the US may also be contributing to an increase in headache severity.

In 2002, Dr. Dawn Marcus noted that pro-inflammatory chemicals called cytokines had been discovered in migraine, and that they had been found to be elevated in obesity.  She conducted a small pilot study (61 headache patients) to look for a relationship between obesity and migraine.  She found that obesity was related to headache impact on a validated test of pain severity, psychological distress, and quality of life.  The test scores were significantly higher in obese patients.

Medical geneticists are currently hard at work to see whether there is a genetic link between migraine, obesity, hyperlipidemia (elevated cholesterol and other blood fats), high blood pressure (hypertension), and other chronic conditions. Research on obesity is moving forward to look at many complex biochemical relationships to learn more.

In 2003, a large study was completed looking at the various risk factors for the development of chronic daily headache.  Some things we already knew about or suspected, like medication overuse, or not sleeping.  But an association with weight was a surprise to headache specialists.

This study, conducted by Dr. Ann Scher and colleagues, involved just over 1,100 people who were followed for a year.  The obese people were far more likely to develop chronic daily headache (not acute migraine) than the normal group.  Chronic daily headache is defined as headaches which occur 15 days a month or more.

Who is Affected by Obesity and Headache?

In a more recent study, Dr. Marcelo Bigal, interviewed over 143,000 people in order to identify nearly 1,100 with chronic daily headache.  Sixty-four per cent of the study population was female.  Obese individuals, those with a body mass index (BMI) of 30 or more, were about twice as likely to develop chronic daily headache, 7% vs. 3.8% for the normal group.  The group who were just in the overweight range,  those with a BMI between 25 and 29.9, had a 5% risk of developing chornic daily headache.  Obese middle-aged women were at greatest risk.

The obese group were also more likely to miss work due to their headaches.  When asked if they had missed more than four days of work, 33% of the obese group answered yes, as compared to 27% of the overweight group and 26% of the underweight group.

Can Weight Loss Help Chronic Headache?

We do not yet know whether weight management will reduce the frequency and severity of headaches.   Some headache specialists feel that this may be so, while others simply suspect that the same risk factors that contribute to obesity also contribute to headache.

Further, if you have chronic headaches, you are less likely to be active or to exercise.

The positive finding is that obese chronic daily headache sufferers were just as responsive to treatment as were other patients.  In a second study, Dr. Bigal and his colleagues compared the treatment outcomes of 170 migraine patients.  They found that after three months of treatment, response rates were about the same in all weight classes.

So, the good news is that whether obesity is the chicken or the egg in chronic daily headache, treatment strategies are still effective.