24 oktober 2005: Bron: Met dank aan Susan en www.lef.org

Een grote 20 jarige studie onder 32000 tweelingen geboren voor 1958 waaronder 12.222 vrouwen toont aan dat de vrouwen die relatief kort slapen, gemiddeld 6 à 7 uur, een groter risicio hebben op het ontwikkelen van borstkanker dan vrouwen die echt lang en goed slapen. We praten hier dan over meer dan 8 uur per nacht gemiddeld. De langslapers bleken een 71% minder groot risico op borstkanker te hebben dan de kort slapers. Een en ander wordt door de onderzoekers verklaard door de aanmaak van melatonine die alleen 's nachts in de slaap wordt aangemaakt. Aanvullende melatonine lijkt dan ook belangrijk voor kankerpatienten en in het bijzonder voor vrouwen met borstkanker blijkt uit deze studie. Achtereenvolgens het abstract van de studie en darna een kort artikel uit Lef met daaronder nog wat citaten uit soortgelijke studies die alle wijzen op effecten van aanvullende melatonine bij kankerprocessen

Cancer Res. 2005 Oct 15;65(20):9595-600.

Sleep duration and breast cancer: a prospective cohort study.

Verkasalo PK, Lillberg K, Stevens RG, Hublin C, Partinen M, Koskenvuo M, Kaprio J.
Department of Environmental Health, National Public Health Institute, Kuopio. pia.verkasalo@ktl.fi

Breast cancer incidence has increased during recent decades for reasons that are only partly understood. Prevalence of sleeping difficulties and sleepiness has increased, whereas sleeping duration per night has decreased. We hypothesized that there is an inverse association between sleep duration and breast cancer risk, possibly due to greater overall melatonin production in longer sleepers. This population-based study includes information from women born in Finland before 1958. Sleep duration, other sleep variables, and breast cancer risk factors were assessed by self-administered questionnaires given in 1975 and in 1981. Breast cancer incidence data for 1976 to 1996 was obtained from the Finnish Cancer Registry. Hazard ratios (HR) and 95% confidence intervals (CI) were obtained from Cox proportional hazards models adjusting for potential confounders. Altogether, 242 cases of breast cancer occurred over the study period among the 12,222 women with sleep duration data in 1975. For these women, the HRs for breast cancer in the short (< or =6 hours), average (7-8 hours), and long sleep (> or =9 hours) duration groups were 0.85 (CI, 0.54-1.34), 1.0 (referent), and 0.69 (CI, 0.45-1.06), respectively. Analysis restricted to the 7,396 women (146 cases) whose sleep duration in 1975 and 1981 were in the same duration group (stable sleepers) yielded HRs of 1.10 (CI, 0.59-2.05), 1.0, and 0.28 (CI, 0.09-0.88), with a decreasing trend (P = 0.03). This study provides some support for a decreased risk of breast cancer in long sleepers.

PMID: 16230426 [PubMed - in process]

Bron: www.lef.org

More sleep reduces breast cancer risk

A study reported in the October 15 2005 issue of the journal Cancer Research is the first to reveal an association between greater sleep length and a reduced incidence of breast cancer.

Researchers in Finland examined data obtained in the Finnish Twin Cohort, which includes over 32,000 twins born before 1958. The current study involved 12,222 female participants who replied to one or more questions concerning sleep duration, quality and sufficiency in 1975 or 1981. Data on breast cancer diagnoses from 1976 to 1996 was obtained from the Finnish Cancer Registry.

During the 30 year period 242 cases of breast cancer were diagnosed. Although women who were classified as having short sleep duration of six hours or less had a modestly lower breast cancer risk than that experienced by those with an average sleep duration of 7 to 8 hours, women who were categorized as long sleepers experienced a 31 percent reduction in the risk of breast cancer compared to average sleepers.

In a separate analysis of 7,396 so-called stable sleepers, whose answers on sleep duration in 1981 were unchanged from those of 1975, short sleepers experienced a 10 percent greater risk of breast cancer than average sleepers, while long sleepers experienced a significant 72 percent reduction compared to average sleepers. The separate analysis was conducted in recognition of the impact of long-term factors on breast cancer risk.

The authors hypothesized that sleep patterns may influence breast cancer risk via changes in melatonin and other hormonal rhythms, and acknowledged that the greater prevalence of artificial lighting at night could be a contributor to the current increase in breast cancer incidence via its ability to reduce melatonin levels. In their discussion of the current study’s findings, they cite studies that support this hypothesis, such as several that have found an association between night shift work and breast cancer risk, or those that have determined a reduction in risk among blind women. They conclude, “The suggestion of lower breast cancer risk in long sleepers in the Finnish Twin Cohort adds to the body of evidence for a possible anticarcinogenic effect of melatonin.”

Insomnia and daytime sleepiness

Sleep is absolutely essential for repair and rejuvenation, and those with chronic insomnia must find a solution in order to maintain quality of life. Most people don't know that chronic insomnia predisposes people to early death. Therefore, from a perspective of extending life, it is absolutely essential that good sleep patterns be restored.

As people age, their sleep quality often undergoes significant deterioration, commonly characterized by frequent and longer-lasting nighttime awakenings. In many older people, sleep disturbance is correlated with a decline in melatonin secretion. A number of published studies also show that decreased melatonin production is also associated with the onset of a host of degenerative diseases.

One report discusses the role of melatonin in reversing partially degraded proteins that lead to the accumulation of lipofuscin (age-pigments in the skin and the brain), cataracts, and crosslinked collagen. The scientist who wrote this article stated that the nighttime rise in melatonin is one way the body "cleans" itself of partially glycated proteins (Yin 2000). If this hypothesis is correct, it helps explain the numerous published studies showing that melatonin protects against a wide range of aging-related diseases.

After darkness, young pineal glands secrete melatonin slowly for about 5 hours to enable the body to enter the various stages of deep sleep, so people can feel revitalized and rejuvenated the next morning. Further, melatonin supplementation has been shown in many scientific studies to be a safe and effective sleep-enhancing therapy (Brown 1994; Garfinkel et al. 1995; Haimov et al. 1995; Zhdanova et al. 1995; Zisapel 1999).


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Reageer op "Borstkanker - Lang en goed slapen 's nachts lijkt beschermend tegen borstkanker. Echte langslapers hadden beduidend minder kans op borstkanker dan kort slapers. Dit alles lijkt te maken te hebben met natuurlijke melatonine aanmaak"

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