A large, population-based study of UK residents demonstrated that a variety of symptoms may be observed in the primary care setting up to a decade before a diagnosis of Parkinson’s disease.

The case-control study examined medical records collected between 1990 and 2018 from the UK National Health Service. The ethnically diverse population included 1,055 patients with Parkinson’s and 1,009,523 age- and sex-matched controls. The study authors used a meta-analysis of prediagnostic features to select variables of interest, which were categorized as comorbidities and risk factors, prediagnostic nonmotor manifestations, and prediagnostic motor manifestations. Data were analyzed for time periods of <2, 2-<5, and 5-10 years before diagnosis.

Patients diagnosed with Parkinson’s were more likely to be older and male, but no association with ethnicity or socioeconomic status was observed. Among comorbidities and risk factors, odds ratios were highest for epilepsy, especially in the period <2 years from diagnosis (OR, 10.00; 95% CI, 1.41-70.99). The nonmotor symptom with the highest odds of subsequent Parkinson’s was memory symptoms (OR, 8.60; 95% CI, 5.91-12.49) within two years of diagnosis. Among motor symptoms, tremor was most highly associated with a Parkinson’s diagnosis, especially within two years of diagnosis (OR, 145.96; 95%CI, 90.55-235.28).

Associations with a subsequent diagnosis of Parkinson’s were also observed for a variety of factors such as depression, rigidity, hypotension, constipation, and anxiety. A novel association between hearing loss in the five years before diagnosis was highlighted by the study authors as another potential sensory processing deficit of Parkinson’s.

Given that patients may seek care for symptoms that appear up to 10 years before a diagnosis, primary care physicians should be aware of the wide range of motor and nonmotor symptoms associated with a future diagnosis of Parkinson’s disease and consider the potential benefits of an early diagnosis for their patients.