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Population study: followed a group

Study that followed 90,317 US adults: coffee drinking linked to lower risk of death

Loftfield and colleagues · American journal of epidemiology · 2015

Original title: Association of Coffee Consumption With Overall and Cause-Specific Mortality in a Large US Prospective Cohort Study.

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What the study found

Points to benefit

8,718 deaths. Risk of death from any cause vs nondrinkers was HR = 0.82 (95% CI: 0.77, 0.88) at 2-3 cups a day and HR = 0.79 (95% CI: 0.72, 0.86) at 4-5 cups. Under 1 cup showed HR = 0.99.

The study at a glance

Type of study
Population study: followed a group
Who or what was studied
90,317 people · US adults without cancer or heart disease at the start, followed up to 2009
What was tested
Compared coffee drinkers with nondrinkers by cups a day
What it measured
The question itself: death from any cause
Who has a stake
No disclosure in PubMed
No disclosure in PubMed; funded by the US National Institutes of Health.
Journal
American journal of epidemiology, 2015
Source
PubMed record 26614599. This page is based on the abstract only.

How much this study counts

  • –Shows a link, not a cause: people chose their own habits, and other differences between them may explain the result.
  • ✓Followed people over time, so habits were recorded before the outcome happened.
  • ✓Large: 90,317 people.
  • ✓Measured the question itself: death from any cause.
  • •The PubMed record has no conflict-of-interest statement.
  • •Summarized from the PubMed abstract only. The full paper may hold details the abstract leaves out.

✓ Strength– Limit• Note

These points come from fixed rules about the type of study, its size and length, what it measured, and who has a stake. Every study on Digestery gets the same rules.

Where this study sits

Each dot is one on-topic paper on this question. Steps near the top answer the question more directly.

↑ Stronger evidence

  1. Trials in people: death from any cause

    0

    Not done yet. This is the step that would answer the question.

  2. Trials in people: other measures

    0

    None among the papers we read.

  3. Trials in people: lab tests or safety

    0

    None among the papers we read.

  4. Population studies

    7

    6 benefit, 1 no difference

    ↑ This study is the ringed dot

  5. Blood levels and genes

    0

    None among the papers we read.

↓ Weaker evidence

  • Points to benefit
  • Mixed
  • No difference
  • No direction
  • Points to harm

How it fits with the other research

The short answer to “Does coffee help you live longer?”

Linked to lower death risk; cause unproven.

Confidence: low. Based on 15 on-topic papers.

Read the full answer

Of the other 6 papers on the same step: 5 benefit, 1 no difference. This one found benefit. It agrees with most of them.

Other papers on the same step

See all 15 studies on this question

How this page was made

Label

First read of the abstract
Claude Sonnet
Independent second read
Claude Haiku
Differences settled
The reviewer corrected 2 fields after reading the abstract. Claude Opus 5.5.
Headline
Claude Sonnet, from the checked study record. A script checked its numbers and wording.
Numbers
Checked against the abstract by a script
“How much this study counts”
Fixed rules, the same for every study
Source check by a person
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