Lack of Association Between Proton Pump Inhibitor Use and Cognitive Decline

Studies of association between use of proton pump inhibitors (PPI) and dementia have yielded conflicting results. We investigated the effects of PPIs on cognitive decline in a study of middle-aged and elderly twins in Denmark.

In a prospective study, we collected data from surveys of middle-aged individuals (46-67 years old; the Middle Aged Danish Twin study) and older individuals (the Longitudinal Study of Aging Danish Twins) who underwent cognitive assessments (a 5-component test battery) over a 10-year period (middle-age study, n = 2346) or a 2-year period (longitudinal study of aging: n = 2475). We determined cumulative use of PPIs 2 years prior study enrollment and during follow up, in defined daily doses (DDDs) of PPIs, using data from a nationwide prescription register. Multi-variable linear regression models were used to examine associations between cumulative PPI use and a composite score of cognitive function at baseline and decreases in scores during the follow-up periods.

Use of PPIs before study enrollment was associated with a slightly lower mean cognitive score at baseline in the middle age study. The adjusted difference in mean score of individuals with high consumption of PPIs (≥400 DDD) was lower than that of non-users in the middle-age study (mean crude score for high PPI use, 43.4 ± 13.1 vs for non-use, 46.8 ± 10.2; adjusted difference of 0.69 points; 95% CI, -4.98 to 3.61). In the longitudinal study of aging twins, individuals with high consumption of PPI had higher adjusted scores than non-users (mean crude score for high PPI use, 35.2 ± 10.8 vs for non-use, 36.2 ± 11.1; adjusted difference of 0.95 points; 95% CI, -1.88 to 3.79). In analyses of cognitive decline, among individuals with high consumption of PPIs in the longitudinal study of aging, the adjusted mean difference between baseline score and follow-up score was lower than that of non-users (mean crude score for high PPI use at baseline, 36.6 ± 10.1 and at follow up, 34.3 ± 12.3 vs for non-use at baseline, 38.1 ± 10.5 and at follow up, 37.6 ± 11.3; adjusted difference of -1.22 points; 95% CI, -3.73 to 1.29). In the middle-age study, users with the highest consumption of PPIs (≥1600 DDD) had slightly less cognitive decline than non-users (baseline mean crude score for high PPI use, 43.4 ± 10.1 and follow-up mean crude score, 41.3 ± 9.7 vs baseline score of 49.1 ± 10.2 for non-users and follow-up score of 46.3 ± 9.9 for non-users; adjusted difference of 0.94 points; 95% CI, -1.63 to 3.50). No stated differences in scores between PPI users and non-users were significant.

In analyzing data from 2 large population-based studies of twins in Denmark, we found no association between PPI use and cognitive decline.