Excess coffee consumption a culprit for poor health

Summary: Too much coffee consumption can increase the risk of osteoarthritis, arthropathy, and obesity, a new study reports. Researchers say drinking more than six cups of coffee a day can increase the risk of ill health.

Source: University of South Australia

Cappuccino, latte or short black, coffee is one of the most commonly consumed drinks in the world. But whether it’s good or bad for your health can be clarified by genetics, as a world-first study from the University of South Australia’s Australian Centre for Precision Health shows that excess coffee consumption can cause poor health.

Using data from over 300,000 participants in the UK Biobank, researchers examined connections between genetically instrumented habitual coffee consumption and a full range of diseases, finding that too much coffee can increase the risk of osteoarthritis, arthropathy (joint disease) and obesity.

In earlier research conducted by Professor Hyppönen and team, six cups of coffee a day were considered the upper limit of safe consumption.

Expert genetic epidemiologist, UniSA’s Professor Elina Hyppönen, says understanding any risks associated with habitual coffee intakes could have very large implications for population health.

“Globally, we drink around three billion cups of coffee each day, so it makes sense to explore the pros and cons of this on our health,” Professor Hyppönen says.

“Typically, the effects of coffee consumption are investigated using an observational approach, where comparisons are made against non-coffee-drinkers. But this can deliver misleading results.

“In this study, we used a genetic approach – called MR-PheWAS analysis – to establish the true effects of coffee consumption against 1117 clinical conditions.

This shows a woman with a cup of coffee

“Reassuringly, our results suggest that, moderate coffee drinking is mostly safe.

“But it also showed that habitual coffee consumption increased the risks of three diseases: osteoarthritis, arthropathy and obesity, which can cause significant pain and suffering for individuals with these conditions.”

Professor Hyppönen says the prevalence of these conditions in Australia and around the world shows how important it is to determine possible causes and influencers of the diseases.

“Excess coffee consumption can lead to increased risks of certain diseases,” Professor Hyppönen says.

“For people with a family history of osteoarthritis or arthritis, or for those who are worried about developing these conditions, these results should act as a cautionary message.

“The body generally sends powerful messages with respect to coffee consumption, so it’s imperative that individuals listen to these when consuming coffee. “While these results are in many ways reassuring in terms of general coffee consumption, the message we should always remember is consume coffee in moderation – that’s the best bet to enjoy your coffee and good health too.”


  • Arthropathy, the most common form of which is arthritis, affects one in seven Australians and more than 54 million adults around the world.
  • Osteoarthritis (a chronic and progressive arthropathy that mostly affects the hands, spine and joints such as hips, knees and ankles) affects an estimated one in 11 Australians, and 300 million people worldwide.
  • Obesity is growing in prevalence worldwide, with nearly 40 per cent of adults over overweight and 13 percent obese. In Australia, 67 per cent of Australian adults are overweight or obese.

About this neuroscience research article

University of South Australia
Media Contacts:
Annabel Mansfield – University of South Australia
Image Source:
The image is in the public domain.

Original Research: Closed access
“Association between habitual coffee consumption and multiple disease outcomes: A Mendelian randomisation phenome-wide association study in the UK Biobank”. by Konstance Nicolopoulos, Anwar Mulugeta, Ang Zhou, Elina Hyppönen.
Clinical Nutrition doi:10.1016/j.clnu.2020.03.009


Association between habitual coffee consumption and multiple disease outcomes: A Mendelian randomisation phenome-wide association study in the UK Biobank

Coffee is the most commonly consumed beverage in the world after water, however the debate as to whether coffee consumption is beneficial or detrimental to health continues. Current evidence of the link between coffee and health outcomes is predominately observational, thus subject to methodological issues such a confounding and reverse causation.

This Mendelian randomisation phenome-wide association study (MR-PheWAS) used information from up to 333,214 participants of White-British ancestry in the UK Biobank to examine the causal association between genetically instrumented habitual coffee consumption and the full range of disease outcomes. We constructed a genetic risk score for habitual coffee consumption and screened for associations with disease outcomes across 1117 case-control series. All signals under false discovery rate controlled threshold (5.8 × 10 −4) were followed by Mendelian randomisation (MR) analyses, with replication in independent data sources where possible.

The initial phenome-wide association analysis identified signals for 13 outcomes representing five distinct diseases. The strongest signal was seen for gout (P = 2.3 × 10 −1 2), but there was notable pleiotropy (P distortion <0.001) and MR analyses did not support an association with habitual coffee consumption (inverse variance weighted MR OR 0.41, 95% CI 0.08 to 2.25, P = 0.31). Support for a possible causal relationship between habitual coffee consumption was only obtained for four distinct disease outcomes, including an increased odds of osteoarthrosis (OR 1.23, 95% CI 1.11 to 1.35), other arthropathies (OR 1.22, 95% CI 1.12 to 1.33) and overweight (OR 1.28, 95% CI 1.05 to 1.56), and a lower odds of postmenopausal bleeding (OR 0.72, 95% CI 0.63 to 0.82). Evidence for an association between habitual coffee consumption and these four diseases was also supported by phenotypic associations with self-reported coffee consumption.

This large-scale MR-PheWAS provided little evidence for notable harm or benefit with respect to higher habitual coffee consumption. The only evidence for harm was seen with respect to osteoarthrosis, other arthropathies and obesity.

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