Animal moulds have revealed that c...

Animal moulds have revealed that calorie restriction enlarges life and protects against tumors, including mammary carcinogenesis. In humans, breast tissue appears to be particularly susceptible to carcinogenic processe in early life and before the first pregnancy. Michels and Ekbom administrationed a retrospective cohort study of the impact of caloric restriction forward the development of breast cancer. Specifically, they studied women with anorexia nervosa strait-laced enough to require hospitalization to determine if these women had a lower incidence of breast cancer than was anticipateed in the general population.

The authors used data from several Swedish Registries to find woman who were hospitalized for anorexia before age 40 between 1965 and 1998 Of the 7303 women identified, 31 were exclud because of a cancer diagnosis before discharge. A standardized incidence ratio calculated the observ number of first primary cancer cases as a ratio to the number of cases wait fored The modifying relationship of parity onward breast cancer incidence was assessed on dividing dividing women into parous and nulliparous groups

In this cohort, 52 women were identified with any impressed sign of cancer during 96,887 person-years of follow-up between 1965 and 2000 The standardized incidence ratio for breast cancer was 047 among women who were diagnosed with anorexia before 40 years of age. These women had a 53 percent lower incidence of breast cancer than women in the Swedish general population. None of the women with anorexia diagnosed before 20 years of age discloseed breast cancer. The number of reckon uponed cases was 2.7. In the form into groups including women aged 20 to 29 years, the actual and count uponed cases were 4.0 versus 64 respectively. In the collection aged 30 to 39 years, there were 30 actual cases and 57 count uponed cases.

In the 73 percent of women who remained nulliparous, the standardized incidence ratio for breast cancer was 077 during 78984 person-years of follow-up; the ratio was 024 during 17903 person-years of follow-up in the parous assign places to The reduced incidence of breast cancer in these disposes was 23 percent in nulliparous women and 76 percent in parous women

The authors establish a significant decrease in breast cancer incidence in the cohort of women with a hospital discharge diagnosis of anorexia compared with the Swedish general population, with additional protection conferr at subsequent pregnancy. These findings are consistent with observations that in developing countries where nutrition is scarce but there is a high birth rate, women have a lower incidence of breast cancer than in affluent countries.

The impact of caloric restriction in the early period of breast increase may be particularly important, as may differentiation of breast tissue during pregnancy in conferring a protective power The authors call for further research to determine if the lower incidence of breast cancer associated with anorexia is proper to caloric restriction on breast solitary abode; squalid development, to amenorrhea and lack of estrogen or to a decreased horizontal of growth factors.

CAROLINE WELLBERY, MD

Michels KB Ekbom A. Caloric restriction and incidence of breast cancer. JAMA March 10 2004;291:1226-30

COPYRIGHT 2004 American Academy of Family Physicians

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