Among the nearly 75,000 men and women free of cardiovascular disease and cancer at baseline in those studies, just over 4,000 had a stroke during the mean 10.2 years of follow-up.
Total dairy consumption didn’t correlate with total risk of stroke or cerebral infarction specifically, nor did full-fat dairy or milk overall.
But intake of low-fat dairy showed inverse associations with risk of total stroke and cerebral infarction (both P=0.03 for trend).
For stroke overall, the multivariate-adjusted relative risks compared with the lowest low-fat dairy intake quintile suggested a threshold effect:
0.88 for the highest intake group (95% CI 0.80 to 0.97)
0.91 for the next highest group with a median of two servings (95% CI 0.82 to 1.00)
0.92 for the middle group with a median of one serving daily (95% CI 0.82 to 1.00)
0.91 for the next lowest intake group with a median of 0.4 servings (95% CI 0.82 to 1.02)
For ischemic stroke, the association with low-fat dairy appeared dose-dependent. The multivariate-adjusted relative risks compared with the lowest, no intake quartile were:
0.87 for the highest intake group (95% CI 0.78 to 0.98)
0.90 for the high-intermediate group (95% CI 0.81 to 1.00)
0.92 for the middle quartile (95% CI 0.82 to 1.02)
0.94 for the low-intermediate group (95% CI 0.83 to 1.06)
None of the individual dairy foods had a significant impact on stroke risk. Few of the Hemorrhagic stroke results came out significant and none were consistent.
Dairy Consumption and Risk of Stroke in Swedish Women and Men
Results - During a mean follow-up of 10.2 years, we ascertained 4089 cases of stroke, including 3159 cerebral infarctions, 583 Hemorrhagic strokes, and 347 unspecified strokes. Consumption of low-fat dairy foods was inversely associated with risk of total stroke (P for trend=0.03) and cerebral infarction (P for trend=0.03). The multivariable relative risks for the highest compared with the lowest quintile of low-fat dairy consumption were 0.88 (95% CI, 0.80–0.97) for total stroke and 0.87 (95% CI, 0.78–0.98) for cerebral infarction. Consumption of total dairy, full-fat dairy, milk, sour milk/yogurt, cheese, and cream/crème fraiche was not associated with stroke risk.
Conclusions - These results suggest that low-fat dairy consumption is inversely associated with the risk of stroke.
Susanna C. Larsson, PhD; Jarmo Virtamo, MD; Alicja Wolk, DMSc
The results persisted when excluding the first 2 years of follow-up and adjusting for history of hypertension, obesity, and diabetes and for vitamins and minerals found in dairy, such as vitamin D and calcium.
The researchers noted that dairy consumption in Sweden is in the top five worldwide and particularly heavy in cheese and sour milk or yogurt consumption.
They cautioned that the study could not exclude the possibility of unknown or residual confounding. Another limitation was the single baseline measure of dairy intake, which may have changed over time.
The study was supported by a research grant from the Swedish Council for Working Life and Social Research, the Swedish Research Council, and by a Research Fellow grant from Karolinska Institute.
The researchers reported having no conflicts of interest to disclose.
Primary source: Stroke: Journal of the American Heart Association
Source reference: Larsson SC, et al “Dairy consumption and risk of stroke in Swedish women and men” Stroke 2012;43: DOI: 10.1161/STROKEAHA.111.641944.