Relationship between serum isoflavone levels and disability-free survival among community-dwelling elderly individuals

Nested case-control study of the Tsurugaya project

Atsushi Hozawa, Yumi Sugawara, Yasutake Tomata, Masako Kakizaki, Toru Tsuboya, Kaori Ohmori-Matsuda, Naoki Nakaya, Shinichi Kuriyama, Akira Fukao, Ichiro Tsuji

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Background.The longer healthy life expectancy observed in Japan may be partly attributed to the Japanese diet. The researchers sought to examine whether serum isoflavone levels are associated with disability and death.Methods.The researchers used a nested case-control study to compare serum isoflavones (daidzein, genistein, glycitein, and equol) levels between 165 participants that died or were certificated as disabled (cases) and 177 controls. Disability was defined by certification of long-term care insurance. Conditional logistic regression models were used to calculate the risk of isoflavones for the composite outcome.Results.The proportion of cases was lower in the group with the highest levels of equol (34/91, 37%) compared with equol nonproducers (84/161, 52%). The risk of disability or death among equol producers remained reduced after adjusting for age and sex (odds ratio: 0.55, 95% confidence interval: 0.33-0.93). In a multivariate model, this risk was also unchanged (odds ratio: 0.51, 95% confidence interval: 0.27-0.96). There were no significant associations between daidzein, genistein, and glycitein with the composite endpoint.Conclusions.Higher serum equol levels, but not any other isoflavones, were inversely associated with the composite endpoint of disability and death. Although it cannot be concluded that equol per se has preventive effects on disability or death, higher equol levels appear associated with better health.

Original languageEnglish
Pages (from-to)465-472
Number of pages8
JournalJournals of Gerontology - Series A Biological Sciences and Medical Sciences
Volume68
Issue number4
DOIs
Publication statusPublished - 01-04-2013

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Equol
Independent Living
Isoflavones
Case-Control Studies
Serum
Genistein
Long-Term Care Insurance
Logistic Models
Odds Ratio
Research Personnel
Confidence Intervals
Sex Ratio
Certification
Life Expectancy
Japan
Diet
Health

All Science Journal Classification (ASJC) codes

  • Ageing
  • Geriatrics and Gerontology

Cite this

Hozawa, Atsushi ; Sugawara, Yumi ; Tomata, Yasutake ; Kakizaki, Masako ; Tsuboya, Toru ; Ohmori-Matsuda, Kaori ; Nakaya, Naoki ; Kuriyama, Shinichi ; Fukao, Akira ; Tsuji, Ichiro. / Relationship between serum isoflavone levels and disability-free survival among community-dwelling elderly individuals : Nested case-control study of the Tsurugaya project. In: Journals of Gerontology - Series A Biological Sciences and Medical Sciences. 2013 ; Vol. 68, No. 4. pp. 465-472.
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abstract = "Background.The longer healthy life expectancy observed in Japan may be partly attributed to the Japanese diet. The researchers sought to examine whether serum isoflavone levels are associated with disability and death.Methods.The researchers used a nested case-control study to compare serum isoflavones (daidzein, genistein, glycitein, and equol) levels between 165 participants that died or were certificated as disabled (cases) and 177 controls. Disability was defined by certification of long-term care insurance. Conditional logistic regression models were used to calculate the risk of isoflavones for the composite outcome.Results.The proportion of cases was lower in the group with the highest levels of equol (34/91, 37{\%}) compared with equol nonproducers (84/161, 52{\%}). The risk of disability or death among equol producers remained reduced after adjusting for age and sex (odds ratio: 0.55, 95{\%} confidence interval: 0.33-0.93). In a multivariate model, this risk was also unchanged (odds ratio: 0.51, 95{\%} confidence interval: 0.27-0.96). There were no significant associations between daidzein, genistein, and glycitein with the composite endpoint.Conclusions.Higher serum equol levels, but not any other isoflavones, were inversely associated with the composite endpoint of disability and death. Although it cannot be concluded that equol per se has preventive effects on disability or death, higher equol levels appear associated with better health.",
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Relationship between serum isoflavone levels and disability-free survival among community-dwelling elderly individuals : Nested case-control study of the Tsurugaya project. / Hozawa, Atsushi; Sugawara, Yumi; Tomata, Yasutake; Kakizaki, Masako; Tsuboya, Toru; Ohmori-Matsuda, Kaori; Nakaya, Naoki; Kuriyama, Shinichi; Fukao, Akira; Tsuji, Ichiro.

In: Journals of Gerontology - Series A Biological Sciences and Medical Sciences, Vol. 68, No. 4, 01.04.2013, p. 465-472.

Research output: Contribution to journalArticle

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T1 - Relationship between serum isoflavone levels and disability-free survival among community-dwelling elderly individuals

T2 - Nested case-control study of the Tsurugaya project

AU - Hozawa, Atsushi

AU - Sugawara, Yumi

AU - Tomata, Yasutake

AU - Kakizaki, Masako

AU - Tsuboya, Toru

AU - Ohmori-Matsuda, Kaori

AU - Nakaya, Naoki

AU - Kuriyama, Shinichi

AU - Fukao, Akira

AU - Tsuji, Ichiro

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N2 - Background.The longer healthy life expectancy observed in Japan may be partly attributed to the Japanese diet. The researchers sought to examine whether serum isoflavone levels are associated with disability and death.Methods.The researchers used a nested case-control study to compare serum isoflavones (daidzein, genistein, glycitein, and equol) levels between 165 participants that died or were certificated as disabled (cases) and 177 controls. Disability was defined by certification of long-term care insurance. Conditional logistic regression models were used to calculate the risk of isoflavones for the composite outcome.Results.The proportion of cases was lower in the group with the highest levels of equol (34/91, 37%) compared with equol nonproducers (84/161, 52%). The risk of disability or death among equol producers remained reduced after adjusting for age and sex (odds ratio: 0.55, 95% confidence interval: 0.33-0.93). In a multivariate model, this risk was also unchanged (odds ratio: 0.51, 95% confidence interval: 0.27-0.96). There were no significant associations between daidzein, genistein, and glycitein with the composite endpoint.Conclusions.Higher serum equol levels, but not any other isoflavones, were inversely associated with the composite endpoint of disability and death. Although it cannot be concluded that equol per se has preventive effects on disability or death, higher equol levels appear associated with better health.

AB - Background.The longer healthy life expectancy observed in Japan may be partly attributed to the Japanese diet. The researchers sought to examine whether serum isoflavone levels are associated with disability and death.Methods.The researchers used a nested case-control study to compare serum isoflavones (daidzein, genistein, glycitein, and equol) levels between 165 participants that died or were certificated as disabled (cases) and 177 controls. Disability was defined by certification of long-term care insurance. Conditional logistic regression models were used to calculate the risk of isoflavones for the composite outcome.Results.The proportion of cases was lower in the group with the highest levels of equol (34/91, 37%) compared with equol nonproducers (84/161, 52%). The risk of disability or death among equol producers remained reduced after adjusting for age and sex (odds ratio: 0.55, 95% confidence interval: 0.33-0.93). In a multivariate model, this risk was also unchanged (odds ratio: 0.51, 95% confidence interval: 0.27-0.96). There were no significant associations between daidzein, genistein, and glycitein with the composite endpoint.Conclusions.Higher serum equol levels, but not any other isoflavones, were inversely associated with the composite endpoint of disability and death. Although it cannot be concluded that equol per se has preventive effects on disability or death, higher equol levels appear associated with better health.

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