Total volume and composition of fluid intake and mortality in older women: a cohort study.
The health benefits of 'drinking at least 8 glasses of water a day" in healthy individuals are largely unproven. We aimed to examine the relationship between total fluid and the sources of fluid consumption, risk of rapid renal decline, cardiovascular disease (CVD) mortality and all-cause mortality in elderly women.



We conducted a longitudinal analysis of a population-based cohort study of 1055 women aged ≥70 years residing in Australia.



The associations between total daily fluid intake (defined as total volume of beverage excluding alcohol and milk) and the types of fluid (water, black tea, coffee, milk and other fluids) measured as cups per day and rapid renal decline, CVD and all-cause mortality were assessed using adjusted logistic and Cox regression analyses.



Over a follow-up period of 10 years, 70 (6.6%) experienced rapid renal decline and 362 (34.4%) died, of which 142 (13.5%) deaths were attributed to CVD. The median (IQR) intake of total fluid was 10.4 (8.5-12.5) cups per day, with water (median (IQR) 4 (2-6) cups per day) and black tea (median (IQR) 3 (1-4) cups per day) being the most frequent type of fluid consumed. Every cup per day higher intake of black tea was associated with adjusted HRs of 0.90 (95% CI 0.81 to 0.99) and 0.92 (95% CI 0.86 to 0.98) for CVD mortality and all-cause mortality, respectively. There were no associations between black tea intake and rapid renal decline, or between the quantity or type of other fluids, including water intake, and any clinical outcomes.



Habitual higher intake of black tea may potentially improve long-term health outcomes, independent of treating traditional CVD risk factors, but validation of our study findings is essential.
Sir Charles Gairdner Hospital Unit, University of Western Australia School of Medicine and Pharmacology, Perth, Western Australia, Australia.|Department of Renal Medicine, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia.
Wai H
WH
Lim
Centre for Kidney Research, Children's Hospital at Westmead, Sydney, New South Wales, Australia.|School of Public Health, Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia.
Germaine
G
Wong
Sir Charles Gairdner Hospital Unit, University of Western Australia School of Medicine and Pharmacology, Perth, Western Australia, Australia.|Centre for Kidney Research, Children's Hospital at Westmead, Sydney, New South Wales, Australia.
Joshua R
JR
Lewis
Department of Medicine, University of Toronto; Division of Nephrology, Toronto General Hospital, Toronto, Ontario, Canada.
Charmaine E
CE
Lok
Department of Nephrology, Monash Medical Centre, Clayton, Melbourne, Australia.|Department of Medicine, Monash University, Clayton, Melbourne, Australia.|Department of Epidemiology and Preventive Medicine, Monash University, Prahan, Melbourne, Australia.
Kevan R
KR
Polkinghorne
Sir Charles Gairdner Hospital Unit, University of Western Australia School of Medicine and Pharmacology, Perth, Western Australia, Australia.|School of Medical and Health Sciences, Edith Cowan University, Perth, Western Australia, Australia.
Jonathan
J
Hodgson
PathWest, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia.
Ee M
EM
Lim
Sir Charles Gairdner Hospital Unit, University of Western Australia School of Medicine and Pharmacology, Perth, Western Australia, Australia.|Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia.
Richard L
RL
Prince
D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D001315:Australia / Q000453:epidemiology; D001628:Beverages / Q000706:statistics & numerical data*; D002318:Cardiovascular Diseases / Q000453:epidemiology*; D003069:Coffee; D015331:Cohort Studies; D060766:Drinking Water; D005260:Female; D005500:Follow-Up Studies; D015577:Geriatric Assessment / Q000706:statistics & numerical data*; D006801:Humans; D007674:Kidney Diseases / Q000453:epidemiology*; D008137:Longitudinal Studies; D011795:Surveys and Questionnaires; D013662:Tea
D003069:Coffee; D060766:Drinking Water; D013662:Tea
EPIDEMIOLOGY; elderly; fluid intake; mortality; tea