1. Vitamin D Deficiency May be to Blame for Soft Bones in Baby’s Skull

Softening of the skull bones in normal-looking babies might reflect vitamin D deficiency during pregnancy, according to a new study accepted for publication in the Journal of Clinical Endocrinology & Metabolism (JCEM). Furthermore, breast-feeding without vitamin D supplementation could prolong the deficiency, which might lead to a risk of serious health problems later in life, including type 1 diabetes and decreased bone density.

“Craniotabes, the softening of skull bones, in otherwise normal newborns has largely been regarded as a physiological condition without the need for treatment,” said Dr. Tohru Yorifuji, of Kyoto University Hospital in Japan. “Our findings, however, show that this untreated condition may be the result of a potentially dangerous vitamin D deficiency.”

For this study researchers evaluated 1,120 newborns for incidence of craniotabes, and at 5-7 days of age, 246 neonates (22 percent) were found to have craniotabes. Researchers also found the incidence of craniotabes had obvious seasonal variations. This clear seasonal variation strongly suggests that the condition is associated with prenatal vitamin D deficiency and likely reflects the amount of sun exposure of pregnant women.

Most importantly, vitamin D deficiency in neonates could persist into later life, especially in breast-fed infants who do not receive a formula containing vitamin D supplementation. In this study, more than half of the breast-fed infants with craniotabes showed statistically significant low levels of serum 25-OH vitamin D, the storage form of vitamin D. Some of those infants also had symptoms of an overactive parathyroid gland consistent with vitamin D deficiency.

Vitamin D deficiency has not received as much attention as it once did, however several recent studies have reported a resurgence of the condition, even in developed countries. Vitamin D deficiency classically presents with skeletal manifestations such as rickets in childhood or the softening of bones in adults. In addition, vitamin D deficiency in adults can also lead to increased incidence of immunological diseases such as multiple sclerosis, type 1 diabetes, or even colorectal cancer.

“Until more research is done on the effects of perinatal vitamin D deficiency, we suggest treating breast-fed infants with craniotabes with vitamin D, or preferably, treating all pregnant women with vitamin D,” said Yorifuji.

Other researchers working on the study include Junko Yorifuji, Shizuyo Nagai, Masahiko Kawai, Toru Momoi, and Tatsutoshi Nakahata of Kyoto University Hospital in Japan; Kenji Tachibana and Hiroshi Hatayama of Adachi Hospital in Japan; and Hironori Nagasaka of Chiba Children’s Hospital in Japan.

A rapid release version of this paper has been published on-line and will appear in the May 2008 issue of JCEM, a publication of The Endocrine Society.

2. Male Contraception: The Right Combination of Hormones Holds the Key

Hormonal contraception may become a safe, effective, and reversible form of birth control for men, according to a new study accepted for publication in the Journal of Clinical Endocrinology & Metabolism (JCEM). The study revealed that the combination of testosterone and progestin suppressed sperm production faster and more completely than testosterone alone.

“It is possible to suppress sperm output to concentrations that are comparable with reliable contraception in most, but not all men,” said Associate Professor Peter Y. Liu of the University of Sydney, Australia, and lead author of the study. “The rate of suppression is comparable to that achieved after a vasectomy.”

Testosterone and other male hormones act as contraceptives by creating negative feedback in a man’s reproductive system, suppressing the production of sperm.

For this study, a team of researchers analyzed all published male hormonal contraceptive studies of at least three months treatment duration from 1990 to 2006.

In a total of 30 studies, 1,756 men between the ages of 18 and 51 were treated with different preparations of testosterone, with or without various preparations of the hormone progestin. Testosterone is the primary male sex hormone. Progestin, a synthetic progesterone, is also used in combination with estrogen for female contraception, but is ordinarily not produced by men.

The analysis revealed that the combination of testosterone and progestin was more effective at suppressing sperm production than testosterone alone. “Progestin co-administered with testosterone increased both the rate and extent of suppression. It also may make long-term hormonal contraception safer by reducing the dose of testosterone needed for maintenance contraception,” said Liu.

The researchers also found that Caucasian men suppressed sperm output faster, but not as completely, as non-Caucasians. Also, younger men with lower natural testosterone levels had faster suppression, but the differences were relatively small.

The findings also revealed that it is difficult to predict which men will respond best to the treatment, suppressing sperm output to levels consistent with reliable male contraception.

“Considerable progress has been made toward finding an effective combination of these two hormones,” said Liu. “However, the current analysis didn’t take into account the different types of progestins, so more research will need to be done to find the optimum therapy.”

Other researcher involved in the study include Drs. Ronald S. Swerdloff (USA), Bradley D. Anawalt (USA), Richard A. Anderson (UK), William J. Bremner (USA), Joerg Elliesen (Germany), Yi-Qun Gu (China), Wendy M. Kersemaekers (The Netherlands), Robert I. McLachlan (Australia), M. Cristina Meriggiola (Italy), Eberhard Nieschlag (Germany), Regine Sitruk-Ware (USA), Kirsten Vogelsong (Switzerland), Xing-Hai Wang (China), Frederick C.W. Wu (UK), Michael Zitzmann (Germany), David J. Handelsman (Australia), and Christina Wang (USA).

The article “Determinants of the Rate and Extent of Spermatogenic Suppression during Hormonal Male Contraception: An Integrated Analysis,” will appear in the May issue of JCEM, a publication of The Endocrine Society.

3. Previously Unrecognized Testosterone Deficiency Common in Men with Type 1 Diabetes

Testosterone deficiency, previously recognized as common in men with type 2 diabetes, is also common in men with type 1 diabetes, according to a new study accepted for publication in the Journal of Clinical Endocrinology & Metabolism (JCEM). These findings suggest that there is a direct link between insulin resistance and reduced testosterone levels in men.

“As testosterone deficiency may contribute to impaired performance, mood, and libido, as well as have adverse impact on cardiovascular risk, these findings demonstrate the presence of a significant and unrecognized problem among men with diabetes,” said Dr. Mathis Grossmann of the University of Melbourne in Australia. “Our findings of insulin resistance as a potential determinant of reduced testosterone levels may represent an important avenue for intervention.”

For this study, researchers conducted a survey of 580 men with type 2 diabetes and 69 men with type 1 diabetes. A subgroup of 262 men with type 2 diabetes was then reassessed after six months. Testosterone levels were measured from blood samples using the Access testosterone assay.

Previous population-studies found an association of reduced testosterone levels in men and type 2 diabetes, however this is the first study to demonstrate a similar prevalence in individuals with type 1 diabetes.

This study raises the question of whether testosterone replacement therapy can reduce insulin resistance or symptoms of hypogonadism in men with diabetes. Researchers, however, stress that the balance of benefits and risks of such treatment is currently unknown and still to be defined by large and long-term clinical trials. Also, while insulin resistance is associated with testosterone deficiency, there is no evidence that insulin sensitizers are able to elevate testosterone levels in men with diabetes.

Other researchers working on the study include Merlin Thomas, Sianna Panagiotopoulos, Ken Sharpe, Richard MacIsaac, Sophie Clarke, Jeffrey Zajac, and George Jerums of the University of Melbourne in Australia.

A rapid release version of this paper has been published on-line and will appear in the May 2008 issue of JCEM, a publication of The Endocrine Society.

4. Diabetes and Nutrition: Carbohydrates; New Hormone Foundation Bilingual Patient Fact Sheet

The Hormone Foundation has published a new bilingual (English/Spanish) patient fact sheet on diabetes and nutrition with a focus on carbohydrates. This fact sheet explains the link between diabetes and nutrition, as well as the important role that carbohydrates play in diabetes. To download free copies and other useful health resources for patients, visit the Foundation's Web site (www.hormone.org).

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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 14,000 scientists, physicians, educators, nurses and students in more than 80 countries. Together, these members represent all basic, applied, and clinical interests in endocrinology. The Endocrine Society is based in Chevy Chase, Md. To learn more about the Society, and the field of endocrinology, visit our web site at www.endo-society.org.