In seven studies involving 76,744 subjects, those who were breastfed as infants had a 39-percent lower risk of developing type 2 diabetes in adulthood. The findings of these seven studies were "broadly consistent, despite widely differing nature of the populations," the authors note in the American Journal of Clinical Nutrition.

In six studies involving 4,800 subjects, levels of insulin -- the body's key blood sugar-regulating hormone -- were marginally lower in breastfed non-diabetic children and adults compared with formula-fed non-diabetic children and adults.

In these studies, fasting blood sugar concentrations were no different in breastfed and formula fed children and adults. However, in infancy, breastfeeding was consistently related to lower concentrations of blood sugar and insulin than was formula feeding. Chronically high levels of insulin raise the risk of heart disease and exacerbate the effect of diabetes.

"On the basis of the published evidence, breastfeeding may provide a degree of long-term protection against the development of type 2 diabetes, which could be of public health importance," Owen and colleagues conclude.

SOURCE: American Journal of Clinical Nutrition, November 2006.

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Contraceptives protect against endometrial cancer

Last Updated: 2006-11-21 16:51:28 -0400 (Reuters Health)

NEW YORK (Reuters Health) - Oral contraceptives and intrauterine devices (IUD) appear to provide long-term protection against endometrial cancer, researchers report in the International Journal of Cancer.

This has been reported by several studies, but few have been conducted in Chinese populations, Dr. Xiao Ou Shu of Vanderbilt University, Nashville, Tennessee, and colleagues note.

To investigate further, the team studied 1,204 women from Shanghai with newly diagnosed endometrial cancer and 1,212 healthy women, matched to the cancer patients for various characteristics. The endometrium is the lining of the uterus, or womb.

Overall, 223 of the cancer patients (18.5 percent) and 302 of the controls (24.9 percent) reported using an oral contraceptive.

After accounting for other known risk factors or protective factors for endometrial cancer, the use of oral contraceptives was associated with a 25 percent reduced risk. The risk decreased with long-term use. After 72 months, the cancer risk was reduced by 50 percent.

This protective effect was maintained, even after 25 years or longer after oral contraceptives were discontinued.

IUD use was associated with a 47 percent lower risk of endometrial cancer. The duration of IUD use, and age when it was first and last use did not significantly alter the association.

The researchers suggest that the "the inverse association between oral contraceptives use and endometrial cancer may be due to the progestin component of oral contraceptives," which may help reduce the overgrowth of cell in the endometrium.

The protective effect of IUDs, they add, may be prompted by "inflammatory actions that eliminate abnormal and precancerous endometrial cells; decreased abnormal cell growth -- a known risk factor for endometrial cancer -- and reduce the concentration of estrogen receptors."

SOURCE: The International Journal of Cancer, November 2006.

Copyright © 2006 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon. Reuters and the Reuters sphere logo are registered trademarks and trademarks of the Reuters group of companies around the world.