The role of dairy fat for the risk of stroke is not yet clear. Adipose tissue reflects long-term fatty acid intake and metabolism. We, therefore, investigated associations for percentages of adipose tissue fatty acids, for which dairy products are a major source (12:0, 14:0, 14:1 cis-9, 15:0, 17:0, 18:1 trans-11 and 18:2 cis-9, trans-11), with incident total stroke and stroke subtypes.
We conducted a case-cohort study within the Danish Diet, Cancer and Health cohort, including all incident stroke cases (n?=?2108) and a random sample of the total cohort (n?=?3186). The fatty acid composition of adipose tissue biopsies was determined by gas chromatography and specific fatty acids were expressed as percentage of total fatty acids. Stroke cases were identified in the Danish National Patient Registry and the diagnoses were individually verified.
We recorded 2108 stroke cases of which 1745 were ischemic, 249 were intracerebral hemorrhages and 102 were subarachnoid hemorrhages. We observed a lower rate of ischemic stroke for a higher adipose tissue percentage of 12:0, 14:0, 15:0, 17:0, 18:1 trans-11 and 18:2 cis-9, trans-11. Adipose tissue percentages of 15:0 and 18:1 trans-11 were also inversely associated with intracerebral hemorrhage, whereas no associations between the adipose tissue fatty acids and subarachnoid hemorrhage were observed. No associations between 14:1 cis-9 and ischemic or hemorrhagic stroke were found.
Our results suggest that a larger percentage in adipose tissue of fatty acids for which dairy products are a major source is associated with a lower rate of ischemic stroke.
Stroke registries can provide information on evidence-based practices and interventions, which are critical for us to understand how stroke care is delivered and how outcomes are achieved. The Registry of Canadian Stroke Network (RCSN) was initiated in 2001 and has evolved over the past decade. In the first two years, we found it extremely difficult to obtain informed consent from the patient or surrogate which led to selection biases in the registry. Subsequently (2003 onwards), under the new health privacy legislation in Ontario, Canada, the RCSN was granted special status as a "prescribed registry" which allowed us to collect data on all consecutive patients at the regional stroke centres without consent. The stroke data was encrypted and all personal contact information had been removed, therefore we could no longer conduct follow- up interviews. To obtain patient outcomes after discharge, we linked the non-consent-based registry database to population-based administrative databases to obtain information on patient mortality, readmissions, socioeconomic status, medication use and other clinical information of interest. In addition, the registry methodology was modified to include a periodic population-based audit on a sample of all stroke patients from over 150 acute hospitals across the province, in addition to continuous data collection at the 12 registry hospitals in the province. The changes in the data collection methodology developed by the RCSN can be applied to other provinces and countries.