Wednesday, July 17, 2013

News Briefs from The Endocrine Society: Vitamin D Deficiency and PFC Exposure

1. Routine Tasks Pose Problems for Older Individuals with Vitamin D Deficiency 
2. PFC Exposure Tied to Altered Thyroid Function
3. Overcoming Anorexia


1. Routine Tasks Pose Problems for Older Individuals with Vitamin D Deficiency  

Study suggests vitamin D supplements could help prevent mobility problems
Vitamin D-deficient older individuals are more likely to struggle with everyday tasks such as dressing or climbing stairs, according to a recent study accepted for publication in The Endocrine Society's Journal of Clinical Endocrinology & Metabolism (JCEM).

Scientists estimate many as 90 percent of older individuals are vitamin D deficient. The vitamin – typically absorbed from sunlight or on a supplementary basis through diet – plays a key role in bone and muscle health. Vitamin D deficiency can lead to a decline in bone density, muscle weakness, osteoporosis or broken bones.

"Seniors who have low levels of vitamin D are more likely to have mobility limitations and to see their physical functioning decline over time," said the study's lead author, Evelien Sohl, MSc, of VU University Medical Center inAmsterdam, theNetherlands. "Older individuals with these limitations are more likely to be admitted to nursing homes and face a higher risk of mortality."

Using data from an ongoing Dutch cohort study (The Longitudinal Aging Study Amsterdam), the researchers examined among two groups – 762 people between the ages of 65 and 88, and 597 people between the ages of 55 and 65 – over the course of six years. Using blood test results, the subjects were split into groups with the highest, moderate and lowest vitamin D levels. To assess mobility limitations, participants were asked about their ability to perform routine tasks, including sitting down and standing up from a chair or walking outside for 5 minutes without resting.

Among the older group of participants, people with the lowest vitamin D levels were 1.7 times more likely to have at least one functional limitation compared to those with the highest vitamin D levels. In the younger cohort, individuals with low vitamin D levels were twice as likely to have at least one physical limitation.

While the majority of the people in the older cohort's top two vitamin D groups did not report any physical limitations, 70 percent of the people with the lowest vitamin D levels had at least one limitation.

In addition, the study found vitamin D-deficient individuals were more likely to develop additional limitations over time. The older cohort reported more mobility issues after three years, while the younger cohort developed additional limitations over the course of six years.

"The findings indicate low vitamin D levels in older individuals may contribute to the declining ability to perform daily activities and live independently," Sohl said. "Vitamin D supplementation could provide a way to prevent physical decline, but the idea needs to be explored further with additional studies."

Other researchers working on the study include: N. van Schoor, R. de Jongh, M. Visser, D. Deeg and P. Lips of the VU University Medical Center.

The article, "Vitamin D Status is Associated with Functional Limitations and Functional Decline in Older Individuals," was published online July 17.

2. PFC Exposure Tied to Altered Thyroid Function 

Endocrine-disrupting chemicals may increase odds of women developing mild hypothyroidism

Exposure to perfluorinated chemicals is linked to changes in thyroid function and may raise the risk of mild hypothyroidism in women, according to a recent study accepted for publication in The Endocrine Society's Journal of Clinical Endocrinology & Metabolism (JCEM).

Perfluorinated chemicals, or PFCs, are compounds used to manufacture fabrics, carpets, paper coatings, cosmetics and a variety of other products. Among humans and wildlife, PFC exposure is widespread, according to the National Institutes of Health's National Institute of Environmental Health Sciences. Because these chemicals break down very slowly, it takes a long time for PFCs to leave the body.

"Our study is the first to link PFC levels in the blood with changes in thyroid function using a nationally representative survey of American adults," said one of the study's authors, Chien-Yu Lin, MD, PhD, of En Chu Kong Hospital in Taiwan.

Women who had higher levels of a PFC called perfluorooctanoate (PFOA) in their blood tended to have elevated levels of the thyroid hormone triiodothyronine (T3). The study also found an increase in levels of T3 and the thyroid hormone thyroxine (T4) in women with higher concentrations of the PFC perfluorohexane sulfonate (PFHxS) in their blood. The levels rose without the pituitary gland signaling the thyroid to produce more hormones, which is the body's natural mechanism for adjusting thyroid hormone levels. Men exposed to higher amounts of PFHxS, however, tended to have lower levels of the T4 hormone.

Even though people with a history of thyroid diseases were excluded from the study, researchers found an association between subclinical, or mild, hypothyroidism and elevated levels of PFOA, PFHxS and perfluorooctane sulfonate (PFOS) in women. Hypothyroidism occurs when the thyroid gland does not produce enough hormones and can cause symptoms such as fatigue, mental depression, weight gain, feeling cold, dry skin and hair, constipation and menstrual irregularities. This relationship needs to be explored and confirmed through additional research, Lin said.

The researchers analyzed data from 1,181 participants in the 2007-2008 and 2009-2010 National Health and Nutrition Examination Survey (NHANES), a population-based survey conducted by the Centers for Disease Control and Prevention (CDC). The study reviewed levels of four different PFCs as well as thyroid function.

"Although some PFCs such as PFOS have been phased out of production by major manufacturers, these endocrine-disrupting chemicals remain a concern because they linger in the body for extended periods," Lin said. "Too little information is available about the possible long-term effects these chemicals could have on human health."

Other researchers working on the study include: L. Wen of En Chu Kong Hospital, L. Lin and T. Su of National Taiwan University Hospital and P. Chen of National Taiwan University College of Public Health.

The article, "Association between Serum Perfluorinated Chemicals and Thyroid Function in U.S. Adults: the National Health and Nutrition Examination Survey 2007-2010," was published online July 17.

3. Overcoming Anorexia

Anorexia nervosa is a serious and potentially life-threatening condition. The Hormone Health Network's patient education fact sheet Anorexia describes the risk factors for this condition and explains the serious health problems it may cause, including heart complications, dehydration and malnutrition, anemia, and tooth decay. The fact sheet outlines risk factors for and warning signs of anorexia, and encourages patients and their loved ones to get help from a team of health care providers, including a physician, mental health professional and dietician.
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Founded in 1916, The Endocrine Society is the world's oldest, largest and most active organization devoted to research on hormones and the clinical practice of endocrinology.  Today, The Endocrine Society's membership consists of over 16,000 scientists, physicians, educators, nurses and students in more than 100 countries. Society members represent all basic, applied and clinical interests in endocrinology. The Endocrine Society is based in Chevy Chase, Maryland. To learn more about the Society and the field of endocrinology, visit our site at www.endocrine.org. Follow us on Twitter at https://twitter.com/#!/EndoMedia.

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