The only thing humans drink more than coffee is water. We consume the equivalent of three billion cups of coffee daily, a veritable ocean of hot brew. A cup starts the day of innumerable people from Kalamazoo to Timbuktu.

So, it makes sense to ask the question: What’s all that coffee doing to our health?

Researchers at the University of South Australia examined data from 300,000 participants in the UK Biobank, which studies genetics and environmental exposures and their connection to disease. The scientists wanted to see if they might be able to associate the impact of coffee consumption on more than eleven-hundred clinical conditions.

In previous work, these researchers had concluded that six cups was the limit of how much coffee could be safely sipped on any given day. For most people, that’s more than enough caffeine to have them wired and climbing the walls late into the evening.

The study, however, offered some reassuring news. Moderate coffee consumption appears to be mostly safe. Let’s exhale a collective sigh of relief. But it’s a different bottom line for those who habitually knock back excessive cups of coffee.

The study’s authors found that habitual coffee consumption appears to heighten the risk of three conditions: obesity, osteoarthritis and arthropathy. Osteoarthritis is the most-common form of arthritis, affecting millions of people around the globe. Arthropathy is any disease of the joints, including arthritis.

Scientists say coffee is a substance to be consumed in moderation to protect our health. True, few of us are downing six cups or more a day. But coffee fanatics need to be mindful of the potential risks.