Analytical analyses
To examine connections anywhere between diet and coronary arrest, i used Cox proportional danger designs stratified of the ages (mo) and you will go after-upwards period to help you guess RRs and you will 95% CIs. Participants have been split into quintiles out-of cumulative average intake off magnesium, potassium, and calcium to attenuate the within-people variation and greatest portray enough time-identity intake ( 18). A blended nutrient eating plan score off magnesium, potassium, and calcium supplements was indeed calculated by delegating things to for every single quintile and summing the fresh products. Players on low quintile (quintile step 1) out of magnesium, potassium, otherwise calcium consumption received step 1 area for every nutrient, members within the next quintile (quintile Sober dating services 2) gotten dos situations, and so forth. Collective averages were determined by firmly taking the fresh mean of all the reported FFQ consumption up to the beginning of each dos-y pursue-upwards period. The newest collective mediocre consumption was utilized to expect coronary attack chance of the time of one’s past returned survey before second realize-right up course.
Multivariate designs were modified to have ages (mo) and you will diary big date (2-y time menstruation) and provided intakes out-of full times (kcal), alcohol (g/d), cigarette, Body mass index, exercise, adult reputation of early myocardial infarction, postmenopausal hormones treatment use, thiazide fool around with, aspirin fool around with, multi vitamin explore, and you may reputation for diabetes, blood pressure level, and you will hypercholesterolemia at the standard. To check getting an excellent linear pattern, we assigned for each quintile this new median value and you will modeled so it adjustable since the an ongoing variable. I checked out the possibility deviation out of linearity that with a probabilities proportion sample to possess analysis regarding a product into the linear term with a design such as the linear name and restricted cubic spline transformations ( 19). I also used analyses you to integrated the step 3 nutritional elements in addition. Magnesium and you will potassium intakes were very correlated (roentgen = 0.79 in the NHS We; roentgen = 0.73 about NHS II), and you may correlations ranging from calcium and potassium intakes (r = 0.forty-two about NHS We; roentgen = 0.41 throughout the NHS II), whereas anywhere between calcium supplements and you will magnesium consumption (roentgen = 0.54 regarding the NHS We; r = 0.56 regarding the NHS II) have been reasonable. Brand new Q sample was utilized to check towards heterogeneity between brand new NHS I and you will NHS II. RRs (±SEs) for each quintile from each cohort were pooled inside the repaired-outcomes activities so you’re able to determine bottom line prices ( 20). Also, the brand new up-to-date meta-study used practical habit ( 20) regarding review to own heterogeneity by using the Q ensure that you playing with repaired consequences design to create summary estimates whenever zero between-training heterogeneity was evident; if not an arbitrary-effects design was used.
To examine the potential effect modification of the association between dietary minerals and stroke risk by age, hypertension, and diabetes, we stratified our multivariate model on age (<60 compared with ?60 y), hypertension (yes compared with no), and diabetes (yes compared with no) and separately tested the significance of an interaction by using a likelihood ratio test for the comparison of the model with interaction terms to the model with only main effects. All P values were 2-sided, and analyses were conducted with SAS 9.2 software (SAS Institute Inc.).
Overall performance
During 31 y regarding pursue-upwards out of 1980 using 2010 about NHS We and twenty-two y away from follow-right up out-of 1989 thanks to 2011 in the NHS II, all in all, 3780 incident coronary attack cases were determined. Of these times, 3237 experience strokes was basically reported regarding NHS I (and 1664 ischemic, 544 hemorrhagic, and 1029 unspecified strokes), and you may 543 incident strokes was in fact noted throughout the NHS II (plus 186 ischemic, ninety five hemorrhagic, and you may 265 unspecified shots). Age-standard features out-of research users in the midpoint throughout the realize-upwards inside 1994 on NHS We and in 1995 to possess brand new NHS II are shown into the Dining table step one. Women which have higher nutrient intake were expected to fool around with aspirin, nutrients, and postmenopausal hormone treatment, more privately effective, less likely to end up being latest smokers than had been females with straight down mineral intake. Studies for females about NHS We and you will NHS II had been combined as we did not observe a significant ranging from-data heterogeneity (Q-statistic P > 0.05).