AgingResearch.NewsJoin free
Environment International

Long-term heat linked to higher death risk in California

Each 5°F increase in long-term average daily maximum temperature was linked to a 5% higher relative risk of death among California cohort participants.

Paper by Anna H. Wu, Jun Yun Wu, Chiuchen Tseng, +13 more authorsIona Cheng · University of California, Irvine · University of California, San Francisco
Graphical abstract from Environment International
Open the figure at full size
Graphical abstract. Wu et al.

Our read

Populations
Studied:
Cohort study of 88,283 California participants in the Multiethnic Cohort Study
What changed:
Death risk was 5% higher per 5°F increase in long-term average daily maximum temperature
The catch:
People in hotter areas could differ in health or living conditions despite adjustments
Why it’s aging research:
It measures an outcome that worsens with age.

Editor of record: Boris Djordjevic · AgingResearch.News

Paper
Follow @agingbrief

The 88,283 California participants in the Multiethnic Cohort Study were followed from a 1993–1996 baseline through 2019 in a prospective observational study. About 70% were African American or Latino. The analysis examined annual averages of daily maximum temperatures at their homes, covering up to 25 years of exposure.

During follow-up, 48,272 participants died. Each 5°F increase in long-term average daily maximum temperature was associated with a 5% higher relative risk of death. The association remained after adjustments for individual and neighborhood characteristics and other climate factors. Heat-wave exposure was also linked to mortality. Higher temperatures were associated with deaths from Alzheimer’s disease and related dementias and from heart diseases.

Why it matters

For understanding survival in later life, the findings support examining sustained heat alongside short heat waves. The authors say the evidence could inform climate-health research and intervention development.

Caveats

People living in hotter areas may have differed in health or living conditions that the adjustments did not fully capture. The California cohort does not establish whether the same pattern holds in other regions.

Where the evidence stands

Fine particulate matter

Cells, mice and humans: replicated by independent labs. Worms or flies: a single group.

C, W, M, H: cells, worms or flies, mice, humans. Dark: independent labs found the same change there. Light: one lab or one study. Outline: nothing yet.

Labs are independent when their papers share no last author and no institution.

Against: findings that point the other way from most findings on the same outcome.

Company ties: findings with an author at a company, or from a paper whose competing-interests statement declares ties to one.

  • 193 independent labs in 39 countries
  • 27 findings against
  • Funders: National Natural Science Foundation of China and others
  • 26 of 716 findings with company ties

Heat waves

Humans: replicated by independent labs. Cells, worms or flies and mice: nothing yet.

C, W, M, H: cells, worms or flies, mice, humans. Dark: independent labs found the same change there. Light: one lab or one study. Outline: nothing yet.

Labs are independent when their papers share no last author and no institution.

Against: findings that point the other way from most findings on the same outcome.

  • 17 independent labs in 9 countries
  • 1 finding against
  • Funders: Coordenação de Aperfeiçoamento de Pessoal de Nível Superior and others

Comments

Be the first to comment.

More on Alzheimer's disease