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Background The association between milk and dairy intake and the incidence of cardiometabolic diseases, cancer and mortality has been evaluated in many studies, but these studies have had conflicting results with no clear conclusion on causal or confounding associations. The present study aims to further address this association by cross-sectional and longitudinal evaluation of the associations between exposure to various types of dairy products and metabolic risk markers among inhabitants in northern Sweden while taking other lifestyle factors into account. Methods Respondents in the Västerbotten Intervention Programme with complete and plausible diet data between 1991 and 2016 were included, yielding 124,934 observations from 90,512 unique subjects. For longitudinal analysis, 27,682 participants with a visit 8–12 years after the first visit were identified. All participants completed a validated Food Frequency Questionnaire. Metabolic risk markers, including body mass index (BMI), blood pressure, serum (S) cholesterol and triglycerides, and blood glucose, were measured. Participants were categorized into quintiles by intake of dairy products, and risk (odds ratios, OR) of undesirable levels of metabolic risk markers was assessed in multivariable logistic regression analyses. In longitudinal analyses, intake quintiles were related to desirable levels of metabolic risk markers at both visits or deterioration at follow-up using Cox regression analyses. Results The OR of being classified with an undesirable BMI decreased with increasing quintiles of total dairy, cheese and butter intake but increased with increasing non-fermented milk intake. The OR of being classified with an undesirable S-cholesterol level increased with increasing intake of total dairy, butter and high fat (3%) non-fermented milk, whereas an undesirable S-triglyceride level was inversely associated with cheese and butter intake in women. In longitudinal analyses, increasing butter intake was associated with deterioration of S-cholesterol and blood glucose levels, whereas increasing cheese intake was associated with a lower risk of deterioration of S-triglycerides. Conclusions Confounding factors likely contribute to the demonstrated association between dairy intake and mortality, and other medical conditions and analyses should be stratified by dairy type. Electronic supplementary material The online version of this article (10.1186/s12937-018-0418-y) contains supplementary material, which is available to authorized users.

Background Chronic, low-grade inflammation is an established risk factor for cardiovascular disease. The inflammatory impact of diet can be reflected by concentrations of inflammatory markers in the bloodstream and the inflammatory potential of diet can be estimated by the dietary inflammatory index (DIITM), which has been associated with cardiovascular disease risk in some previous studies. We aimed to examine the association between the DII and the risk of first myocardial infarction (MI) in a population-based study with long follow-up. Method We conducted a prospective case–control study of 1389 verified cases of first MI and 5555 matched controls nested within the population-based cohorts of the Northern Sweden Health and Disease Study (NSHDS), of which the largest is the ongoing Västerbotten Intervention Programme (VIP) with nearly 100 000 participants during the study period. Median follow-up from recruitment to MI diagnosis was 6.4 years (6.2 for men and 7.2 for women). DII scores were derived from a validated food frequency questionnaire (FFQ) administered in 1986–2006. Multivariable conditional logistic regression models were used to estimate odds ratios (OR) and 95% confidence intervals (CI), using quartile 1 (most anti-inflammatory diet) as the reference category. For validation, general linear models were used to estimate the association between the DII scores and two inflammatory markers, high-sensitivity C-reactive protein (hsCRP) and interleukin 6 (IL-6) in a subset (n = 605) of the study population. Results Male participants with the most pro-inflammatory DII scores had an increased risk of MI [ORQ4vsQ1 = 1.57 (95% CI 1.21–2.02) P trend = 0.02], which was essentially unchanged after adjustment for potential confounders, including cardiovascular risk factors [ORQ4vsQ1 = 1.50 (95% CI 1.14–1.99), P trend = 0.10]. No association was found between DII and MI in women. An increase of one DII score unit was associated with 9% higher hsCRP (95% CI 0.03–0.14) and 6% higher IL-6 (95% CI 0.02–0.11) in 605 controls with biomarker data available. Conclusion A pro-inflammatory diet was associated with an elevated risk of first myocardial infarction in men; whereas for women the relationship was null. Consideration of the inflammatory impact of diet could improve prevention of cardiovascular disease. Electronic supplementary material The online version of this article (doi:10.1186/s12937-017-0243-8) contains supplementary material, which is available to authorized users.

Background: Although carbohydrate reduction of varying degrees is a popular and controversial dietary trend, potential long-term effects for health, and cancer in specific, are largely unknown. Methods: We studied a previously established low-carbohydrate, high-protein (LCHP) score in relation to the incidence of cancer and specific cancer types in a population-based cohort in northern Sweden. Participants were 62,582 men and women with up to 17.8 years of follow-up (median 9.7), including 3,059 prospective cancer cases. Cox regression analyses were performed for a LCHP score based on the sum of energy-adjusted deciles of carbohydrate (descending) and protein (ascending) intake labeled 1 to 10, with higher scores representing a diet lower in carbohydrates and higher in protein. Important potential confounders were accounted for, and the role of metabolic risk profile, macronutrient quality including saturated fat intake, and adequacy of energy intake reporting was explored. Results: For the lowest to highest LCHP scores, 2 to 20, carbohydrate intakes ranged from median 60.9 to 38.9% of total energy intake. Both protein (primarily animal sources) and particularly fat (both saturated and unsaturated) intakes increased with increasing LCHP scores. LCHP score was not related to cancer risk, except for a non-dose -dependent, positive association for respiratory tract cancer that was statistically significant in men. The multivariate hazard ratio for medium (9–13) versus low (2–8) LCHP scores was 1.84 (95% confidence interval: 1.05-3.23; p-trend = 0.38). Other analyses were largely consistent with the main results, although LCHP score was associated with colorectal cancer risk inversely in women with high saturated fat intakes, and positively in men with higher LCHP scores based on vegetable protein. Conclusion: These largely null results provide important information concerning the long-term safety of moderate carbohydrate reduction and consequent increases in protein and, in this cohort, especially fat intakes. In order to determine the effects of stricter carbohydrate restriction, further studies encompassing a wider range of macronutrient intakes are warranted.