Low Serum Vitamin D and Hip Fracture Risk

A new study published in the Annals of Internal Medicine showed that low vitamin D levels in the blood are associated with an increased risk of hip fracture in postmenopausal women. The study included 800 individuals (400 who had hip fractures, matched with 400 women who did not have hip fractures). Hip fracture risk was highest among women who had the lowest levels of vitamin D in their serum.

As we know, there is an association between low vitamin D levels and obesity. Also, after bariatric surgery, there is a possibility of developing low serum levels if supplementation is not taken regularly. Those were discussed before here and here.

Reference:

Cauley JA, LaCroix AZ, Wu L, Horwitz M, Danielson ME, Bauer DC, Lee JS, Jackson RD, Robbins JA, Wu C, Stanczyk FZ, LeBoff MS, Wactawski-Wende J, Sarto G, Ockene J, Cummings SR. Serum 25-Hydroxyvitamin D Concentrations and Risk for Hip Fractures. Ann Intern Med. 2008 August;149:242-250. (Summary for Patients, Abstract)

Bone Health, Vitamin D, and Obesity - Again!

Vitamin D deficiency is common with obesity. When vitamin D is deficient, calcium tends to be deficient, too. But the body has a way of keeping the calcium level in the blood looking normal. That is, by raising the level of a hormone called "parathyroid hormone" (has nothing whatsoever to do with thyroid hormone), calcium is actually taken away (say, stolen away) from the bones, to keep its level looking normal in the blood. The bones lose calcium, and become weaker, more fragile and more likely to break. We are talking osteopenia and osteoporosis.

A new study from the University of Nebraska Medical Center, Omaha, was published recently in the Journal "Obesity Surgery". The study found out that vitamin D deficiency is common in obese patients at the time of bariatric (weight loss) surgery and is also accompanied by an increased level of parathyroid hormone, approximately half the time. So, vitamin D deficiency after bariatric surgery is not purely a complication of bariatric surgery. It is, at least in part, caused by vitamin D deficiency before the surgery itself. To reach those conclusions, the authors did blood tests to measure the levels of 25-hydroxyvitamin D, iPTH (intact parathyroid hormone), and calcium in 41 patients before undergoing Roux-en-Y gastric bypass. Then, they compared them to healthy non-obese matched controls. About half of the pre-bariatric surgery patients had elevated hyperparathyroid hormone level, compared to only 2% of controls. Levels of vitamin D (25-hydroxyvitamin D) were significantly low in more than half of the obese patients.

This actually reminds us of a previous study that we reported here. In that study, from Maine, before bariatric surgery, 34% of patients had suboptimal levels, and 54% had deficient levels, of 25-hydroxyvitamin D in their blood. By one year after Roux-en-Y gastric bypass surgery, the vitamin D deficiency improved remarkably with the intake of vitamin D supplements. The researchers actually recommended higher-than-average doses of vitamin D supplementation.

Reference Article:

Goldner WS, Stoner JA, Thompson J, Taylor K, Larson L, Erickson J, McBride C. Prevalence of vitamin d insufficiency and deficiency in morbidly obese patients: a comparison with non-obese controls. Obes Surg. 2008 Feb;18(2):145-50. [PMID: 18175194] (Abstract)

More References:

Nelson ML, Bolduc LM, Toder ME, Clough DM, Sullivan SS. Correction of preoperative vitamin D deficiency after Roux-en-Y gastric bypass surgery. Surg Obes Relat Dis. 2007 Jul-Aug;3(4):434-7. [PMID: 17400028] (Abstract)

Hair Loss after Weight Loss Surgery

Here is a common question: Will I lose all my hair after gastric bypass? How do I keep my hair from falling out? The reality is that hair loss after bariatric surgery is common. But patients do not lose all their hair. In the most severe cases, patients may find clumps of hair in their hair brushes, or in the shower drain. However the hair loss normally corrects itself. The most accepted explanation is inadequate protein intake. Hair loss tends to start about three to five months after surgery. The best way to prevent hair loss is to make sure that you take your proteins first, with each meal.

Hair loss after bariatric surgery is considered a type of Telogen Effluvium. To explain, we need to talk a little bit about the normal phases of the cycle of hair development. Each strand of hair goes through three stages of development. These stages are Anagen – the growing phase, Catagen – the intermediate or transitional phase, and Telogen – the resting phase.

Anagen (The Growth Phase): Lasts 2-6 years. About 85% of all the hairs are in the growth phase at any given period of time.

Catagen (The Transitional Phase): The outer root sheath of the hair follicle shrinks and stops producing hair. The catagen phase usually lasts 2-3 weeks.

Telogen (The Resting Phase) The hair does not grow at all. This phase lasts about 3 months (100 days). An average of 5-15% of all hair is in the resting phase at any given period of time. At the end of this phase, the hair follicle starts a new Anagen phase. The resting (telogen) hair remains in the follicle until it is pushed out by growth of a new anagen hair, unless it was shed earlier. There is some recent evidence suggesting that shedding of a telogen hair might be an active process, independent of an emerging anagen hair.

Telogen effluvium occurs when an event prematurely terminates anagen and causes an abnormally high number of normal hairs to enter the resting, or telogen phase. Not all hair enters the telogen phase, but the percentage is much higher than normal. The hairs that are shed due to telogen effluvium are in the telogen phase. Examples of such events include childbirth, gastric bypass surgery, crash diets with inadequate protein intake, acute blood loss, and high fever. Notice that the follicle is not diseased. Simply, the hair follicle’s biologic clock has been reset. On the average, telogen hair loss occurs 3 months after the event.

For the record, this is very different from another type of hair loss called "Anagen Effluvium". The latter is abrupt loss of hair in the anagen phase, which may be caused by cancer chemotherapy and irradiation therapy. This is very different from telogen effluvium.

In conclusion, hair loss after bariatric surgery (a form of acute telogen effluvium) is fully reversible. Patients never completely lose all their scalp hair, although the hair can be very thin. The hair follicles are not irreversibly affected. With restoration of the nutritional balance, helped by increasing the intake of proteins, hair regrowth is expected within 3 - 6 months.

Vitamin D supplements and Obesity

Did you know that there is a high incidence of vitamin D deficiency with obesity? The reason is probably that vitamin D is fat-soluble, so it deposits in the fat stores, and becomes less available to the body. There is a possibility that lack of adequate sun exposure, which is common in Seattle area and in the Northern regions, could contribute to a baseline vitamin D deficiency. This means that a typical patient most likely has a deficit of vitamin D before bariatric (weight loss) surgery. A study from the University of Maine, that was recently published in the journal "Surgery for Obesity and Related Diseases" (1) , showed the results of evaluating how adequate the correction of vitamin D deficiency is, one year after gastric bypass surgery. Before surgery, 34% of patients had suboptimal levels, and 54% had deficient levels, of 25-hydroxyvitamin D in their blood. By one year after Roux-en-Y gastric bypass surgery, the vitamin D deficiency improved remarkably with the intake of vitamin D supplements. Remember, nutritional supplements after weight loss surgery are not optional, they are a must. The researcher recommended higher doses of vitamin D than the average.



Vitamin D is essential for bone health. Calcium absorption requires vitamin D. Lack of calcium leads to osteopenia and osteoporosis. So, when you take your supplements, particularly after bariatric surgery, make sure that they include calcium and vitamin D. Actually, it may be better to start before having the surgery. Notice, though, that there are medical conditions in which taking extra calcium may be contraindicated. Therefore, make sure that your physician is OK with it. Also, after gastric bypass, the general recommendation is to take the calcium supplements in the form of calcium citrate, not carbonate. There is some controversy in that issue, but taking calcium citrate will keep you on the safer side, with regards to calcium absorption.



So, make sure that you take your nutritional supplements regularly, and stay healthy.



Reference:



(1) Nelson ML, Bolduc LM, Toder ME, Clough DM, Sullivan SS. Correction of preoperative vitamin D deficiency after Roux-en-Y gastric bypass surgery. Surg Obes Relat Dis. 2007 Jul-Aug;3(4):434-7. [PMID: 17400028]