Folate Intake and Risk of Breast Cancer Characterized by Hormone Receptor Status

Zhang, Shumin M.; Hankinson, Susan E.; Hunter, David J.; Giovannucci, Edward; Colditz, Graham A.; Willett, Walter C.

doi:10.1158/1055-9965.epi-05-0083

Cited by 70 publications

(65 citation statements)

References 42 publications

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“…There are several possible explanations. Some of the previous prospective studies reported inverse associations specifically among moderate to high alcohol consumers (21,22) or with estrogen receptor -negative breast cancer cases (23,24). Because alcohol intake was relatively low in our population (our highest category of alcohol was z5 g/d), we were not able to examine the association among higher alcohol drinkers.…”

Section: Nutrients In One-carbon Metabolism and Breast Cancer Cancer mentioning

confidence: 90%

Nutrients Involved in One-Carbon Metabolism and Risk of Breast Cancer among Premenopausal Women

Cho¹,

Holmes²,

Hankinson³

et al. 2007

Cancer Epidemiology, Biomarkers &Amp; Prevention

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Folate, vitamin B6, vitamin B12, methionine, choline, and betaine are nutrients involved in one-carbon metabolism and have been hypothesized to reduce the risk of breast cancer. However, previous epidemiologic studies on most of these nutrients and breast cancer risk have been inconclusive and have included primarily postmenopausal women. No study has examined choline and betaine in relation to breast cancer risk. Therefore, we examined the intake of these nutrients in relation to breast cancer risk among 90,663 premenopausal women ages 26 to 46 years in 1991 in the Nurses' Health Study II. Nutrient intake was assessed with a validated food frequency questionnaire in 1991, 1995, and 1999. During 12 years of follow-up from 1991 to 2003, we documented 1,032 incident cases of invasive breast cancer. Overall, none of the nutrients was associated with risk of breast cancer. The results were similar by levels of alcohol intake and folate intake and for estrogen receptor-negative breast cancer. In conclusion, we found no evidence that higher intakes of nutrients involved in one-carbon metabolism reduce risk of breast cancer among premenopausal women. (Cancer Epidemiol Biomarkers Prev 2007;16(12):2787-90)

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Section: Nutrients In One-carbon Metabolism and Breast Cancer Cancer mentioning

confidence: 90%

Nutrients Involved in One-Carbon Metabolism and Risk of Breast Cancer among Premenopausal Women

Cho¹,

Holmes²,

Hankinson³

et al. 2007

Cancer Epidemiology, Biomarkers &Amp; Prevention

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“…1͑a͒ the spectra of solutions with different concentrations are shown. The sharper peak at 295 nm could be attributed to carbazole moiety 17 and the broad region centered on 320 nm may be attributed to the -‫ء‬ transition. The region between 382 and 413 nm of higher concentrated solutions is depicted in Fig.…”

Section: A Absorption Propertiesmentioning

confidence: 98%

The photophysics of singlet, triplet, and degradation trap states in 4,4-N,N′-dicarbazolyl-1,1′-biphenyl

Jankus

Winscom

Monkman

2009

The Journal of Chemical Physics

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In this paper we report the results of optical characterization of 4,4-N,N′-dicarbazolyl-1,1′-biphenyl (CBP), known as a host material for phosphorescent light emitting devices. Using absorption, steady state, and time-resolved spectroscopy, we explore the singlet and triplet states in solid and solution samples of CBP. In solutions we observe two distinct short-lived states with well-resolved emission originating from individual molecule singlet states (at 365 and 380 nm) and “quenching” low energy (LE) states (at 404 and 424 nm). The latter are seen only in saturated solutions and solid samples. Both of those species have different lifetimes. After UV exposure of very concentrated degassed solution the intensities of the LE bands starts to decrease. The longer the solution is exposed to UV, the less emission is seen at 404 and 424 nm, until it is totally gone. The spectrum of the highly concentrated solution is then the same as the spectrum of dilute solution, i.e., only emission at 365 and 380 nm is present. An increase in intensities of the singlet emission peaks correlates with an increase in UV exposure time. Similar behavior is observed in evaporated CBP film. We propose that this behavior is due to chemical instability of the weak N–C bonding of carbazolyl moiety—this creates new degradational species over time which dissociate after exposure to UV. We believe this to be the reason for variation in CBP fluorescence and delayed fluorescence spectra recorded by various research groups. Further, we detected two types of very long-lived states. One of these states (higher energy) is ascribed to molecular phosphorescence emission, the other to emission from low energy triplet trap states which we relate to degradational species. We propose that triplets are more easily caught by these latter sites when their hopping rate increases, and they emit inefficiently from these lower energy sites.

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“…Choline can convert to betaine, which can donate the methyl group to homocysteine as does folate, although the donation of the methyl group by betaine is limited to the liver and the kidney. Although two meta-analyses did not find an overall association between folate intake and breast cancer risk (Lewis et al, 2006;Larsson et al, 2007), in some studies, folate intake was inversely associated with breast cancer risk in the whole population (Ericson et al, 2007), or among alcohol drinkers (Zhang et al, 1999;Rohan et al, 2000), or with certain hormone receptor types of breast cancer (Zhang et al, 2005;Larsson et al, 2008;Maruti et al, 2008). Choline and betaine may reduce the risk of breast cancer in a manner similar to that of folate.…”

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confidence: 97%

Choline and betaine intake and risk of breast cancer among post-menopausal women

et al. 2010

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BACKGROUND: Choline and betaine, similar to folate, are nutrients involved in one-carbon metabolism and hypothesised to reduce breast cancer risk. No prospective study among post-menopausal women has examined choline and betaine intakes in relation to breast cancer risk. METHODS: We examined the intake of choline and betaine and breast cancer risk among 74 584 post-menopausal women in the Nurses' Health Study. Nutrient intake was assessed using a validated food-frequency questionnaire six times since 1984. During 20 years of follow-up from 1984 until 2004, we documented 3990 incident cases of invasive breast cancer. RESULTS: Overall, choline (mean ± s.d.; 326 ± 61 mg per day) and betaine (104 ± 33 mg per day) intake was not associated with a reduced risk of post-menopausal breast cancer. Participants in the highest quintile of intakes had multivariate relative risks of 1.10 (95% confidence interval (95% CI): 0.99 -1.22; P-value, test for trend ¼ 0.14) for choline and 0.98 (95% CI: 0.89 -1.09; P-value, test for trend ¼ 0.96) for betaine, compared with those in the lowest quintiles of intakes. The results were similar in breast cancer stratified by hormone receptor (oestrogen receptor/progesterone receptor) status. The association between choline intake and breast cancer risk did not differ appreciably by alcohol intake (non-drinker, o15 or 15 þ g per day) or several other breast cancer risk factors, including family history of breast cancer, history of benign breast disease, body mass index, post-menopausal hormone use, and folate intake. CONCLUSION: We found no evidence that higher intakes of choline and betaine reduce risk of breast cancer among post-menopausal women.

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Folate Intake and Risk of Breast Cancer Characterized by Hormone Receptor Status

Cited by 70 publications

References 42 publications

Nutrients Involved in One-Carbon Metabolism and Risk of Breast Cancer among Premenopausal Women

Nutrients Involved in One-Carbon Metabolism and Risk of Breast Cancer among Premenopausal Women

The photophysics of singlet, triplet, and degradation trap states in 4,4-N,N′-dicarbazolyl-1,1′-biphenyl

Choline and betaine intake and risk of breast cancer among post-menopausal women

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