Takeaway

Women using proton pump inhibitors (PPIs) may have reduced risk for female cancers, according to a 16-year population-based nationwide study from Taiwan.
The reduced risk was greatest for breast and ovarian cancers in 20- to 64-year-old women, and cervical and endometrial cancer in 40- to 64-year-old women.
No reduced risk was expressly seen in older women.

Why this matters

Findings suggest that PPIs may prevent female cancers in nonelderly women.
The use of PPIs has rapidly increased in recent years based on their effectiveness for gastroesophageal reflux disease and peptic ulcer disease.
Many people use PPIs over the long term.
Findings have biological plausibility based on the PPI-induced reduction of intracellular pH, which has cancer-preventive properties.

Study design

Nested case-control study in a cohort of 23 million individuals in Taiwan's Health and Welfare Data Science Center database of medication and diagnostic information (2000-2016).
Cancers were pathologically confirmed through linkage with the population-based Taiwan Cancer Registry.
PPI use (for at least 2 months within the 2 years before the index cancer diagnosis) was compared among nested cases of newly diagnosed female cancer (n=233,173) versus nested controls without female cancer (n=932,692) over the 16-year period matched on age, sex, and visit date.
The association between PPI use and female cancer was adjusted for potential confounders that included medication use (metformin, aspirin, and statins, which are also known to reduce cancer risk).
Funding: Taiwan's National Science and Technology Council; Ministry of Education in Taiwan.

Key results

Overall, PPI use was associated with a 14% reduction in the risk for incident female cancers (aOR, 0.86; 95% CI, 0.80-0.91).
Risk reduction was seen in incident breast and ovarian cancers among 20- to 39-year-old women:
- Breast cancer: aOR, 0.69; 95% CI, 0.56-0.84, a 31% reduction.
- Ovarian cancer: aOR, 0.58; 95% CI, 0.34-0.99, a 42% reduction.
Risk reduction was also seen in incident breast and ovarian cancers among 40- to 64-year-old women:
- Breast cancer: aOR, 0.89; 95% CI, 0.86-0.94, an 11% reduction.
- Ovarian cancer: aOR, 0.87; 95% CI, 0.75-0.99, a 13% reduction.
Risk reduction was also seen in incident cervical and endometrial cancers among 40- to 64-year-old women:
- Cervical cancer: aOR, 0.79; 95% CI, 0.73-0.86, a 21% reduction.
- Endometrial cancer: aOR, 0.72; 95% CI, 0.65-0.81, a 28% reduction.
No significant associations were seen in women aged ≥65 years.

Limitations

Retrospective observational design.
Findings were not causal.
There was no information on patients' lifestyles, medication adherence, PPI dosage, and laboratory data.

Proton pump inhibitor use linked to lower risk for female cancers

November Challenge