A research group including Specially Appointed Assistant Professor (Full Time) Yuko Nakamura and Professor Ryohei Yamamoto of the Health and Counseling Center of the University of Osaka examined alcohol consumption and decline in estimated glomerular filtration rate (eGFR) in men and women aged 40–74 who underwent annual health checkups in Osaka Prefecture. The result showed that men who drank the equivalent of two cups of sake (approx. 360 ml, 40g of alcohol) per day had a higher risk of 30% or greater decline in kidney function (Fig. 1).

Ministry of Health, Labour and Welfare advocates that the appropriate amount of alcohol is the equivalent of one cup of sake (approx. 180 ml) per day, and that drinking more than this can pose health risks. Regarding the kidneys, the largest epidemiological study to date, which involved 304,929 Japanese people (125,698 men and 179,231 women), reported that drinking less than 360 ml of alcohol per day did not result in a decline in kidney function, but men who drank 540 ml or more of alcohol per day were at a higher risk of kidney function decline. However, the relevance of between 360 ml and 540 ml of alcohol per day and declining kidney function was not well understood.

The research group examined the relationship between alcohol consumption and kidney function among 169,272 in the National Health Insurance system (80,765 men and 88,507 women) who underwent annual health checkups in Osaka Prefecture between FY 2012 and FY 2017.

The results showed that men who drank the equivalent of 360 ml of Japanese sake (a traditional Japanese alcoholic beverage) or more per day have 30% or higher risk of decline in kidney function compared to non-drinkers. On the other hand, no association was seen between alcohol consumption and kidney function in women. This finding is expected to lead to effective health guidance, such as risk assessment based on the amount of alcohol consumed and guidance on lifestyle improvement.

Fig. 1 Alcohol consumption and 30% or greater decline in kidney function
Credit: Yuko Nakamura

Research Background

Previous epidemiological studies examining the relationship between excessive alcohol consumption and kidney function have had conflicting results due to the inconsistent definition, with some studies defining it as "more than 180 ml of sake per day" and others as "more than 360 ml of sake per day." A large-scale epidemiological study conducted recently on 304,929 Japanese people (125,698 men and 179,231 women) followed for a median period of 1.9 years found that drinking less than 360 ml of sake per day did not result in a decline in kidney function, but that drinking 540 ml or more sake per day was associated with a higher risk of kidney function decline in men. However, no clear conclusions have been obtained regarding the relationship between drinking more than 360 ml but less than 540 ml of sake per day and kidney function. Furthermore, it is known that women are more susceptible to the effects of alcohol than men, and gender differences in the effects were also considered. Considering these factors, it was necessary to establish detailed categories of alcohol consumption and examine the association with kidney function by gender.

Research Contents

Using data from 169,272 people (80,765 men and 88,507 women) who underwent health checkups in Osaka Prefecture between FY 2012 and FY 2017, the researchers examined the relationship between the amount of alcohol consumed and estimated glomerular filtration rate (eGFR) separately for men and women. The amount of alcohol consumed was classified into six categories: ① do not drink, ② drink occasionally, ③ drink less than 180 ml, ④ drink between 180 ml and 360 ml, ⑤ drink between 360 ml and 540 ml, and ⑥ drink more than 540 ml. Over a median observation period of 2.8 years, 1,231 men (1.5%) had a 30% or greater decline in kidney function. In particular, the groups who drank more than 360 ml of alcohol daily (categories ⑤ and ⑥) were shown to have a higher risk of kidney function decline compared to the group who did not drink alcohol (category ①). (When category ① was used as the base [risk = 1.00], the risks for categories ② to ⑥ were 1.05 times [95% confidence interval 0.87–1.27], 0.99 times [0.80–1.21], 1.05 times [0.88–1.26], 1.23 times [1.01–1.51], and 1.61 times [1.22–2.11], respectively.) On the other hand, the number of women who drank alcohol was low, so a thorough study could not be done.

Social Impact of the Research

Ministry of Health, Labour and Welfare advocates that the appropriate amount of alcohol is the equivalent of one cup of sake (approx. 180 ml) per day, and that drinking more than this can pose health risks.

Regarding the kidneys, the largest epidemiological study to date reported that drinking less than 360 ml of alcohol per day did not result in kidney function decline, but men who drank 540 ml or more of alcohol per day were at a higher risk of kidney function decline. This study suggests that drinking more than 360 ml of alcohol per day may increase the risk of kidney dysfunction in men. This result suggests that the effects of alcohol on kidney function may appear at lower amounts than previously thought, necessitating more careful risk assessment of the amount of alcohol consumed in kidney.

Notes

The article, “Alcohol Consumption and Incidence of Decline in Glomerular Filtration Rate and Proteinuria: The Osaka Kenko Innovation (TOKI) Study,” was published in an international medical journal of Journal of Nephrology (online) at DOI: https://doi.org/10.1007/s40620-025-02339-w.

Links

• Professor Yamamoto’s Profile
• Specially Appointed Assistant Professor Nakamura’s Profile