#### The bottom line Vitamin D has gained much attention in research and clinical practice as a possible preventive factor for a wide array of chronic diseases, including cardiovascular disease, various cancers, type 2 diabetes, autoimmune diseases, and chronic obstructive pulmonary disease. Vitamin D3 (cholecalciferol) is a steroid hormone precursor and is synthesised when skin is exposed to ultraviolet B radiation. It is also found in a limited number of foods, especially oily fish. The other form of the vitamin, vitamin D2 (ergocalciferol), is found in dietary plant sterols exposed to ultraviolet B radiation and is somewhat less effective than vitamin D3.1 Vitamin D has well known effects on calcium metabolism and is traditionally linked to the prevention of rickets in children. It is also now clear that vitamin D deficiency causes bone loss through secondary hyperparathyroidism.2 Because vitamin D receptors are present in many organs and tissues, vitamin D may have extraskeletal effects.2 In addition, many observational studies have shown associations between 25-hydroxyvitamin D3 (25(OH)D3), the major circulating form of vitamin D, and the risk of chronic diseases.3 As a consequence of increased popularity, measurement of 25(OH)D3 to determine vitamin D status has become common, and vitamin D supplements, at doses far exceeding the recommended daily allowances or dietary reference values,4 5 6 are often given, despite limited evidence of an effect. ### What are the possible benefits? On the basis of the existing evidence, we can conclude that vitamin D …

Immigrants to Norway from South Asia and Former Yugoslavia have high levels of cardiovascular disease (CVD) risk factors. Yet, the incidence of CVD among immigrants in Norway has never been studied. Our aim was to study the burden of acute myocardial infarction (AMI) and stroke among ethnic groups in Norway. We studied the whole Norwegian population (n = 2 637 057) aged 35–64 years during 1994–2009. The Cardiovascular Disease in Norway (CVDNOR) project provided information about all AMI and stroke hospital stays for this period, as well as deaths outside hospital through linkage to the Cause of Death Registry. The direct standardization method was used to estimate age standardized AMI and stroke event rates for immigrants and ethnic Norwegians. Rate ratios (RR) with ethnic Norwegians as reference were calculated using Poisson regression. The highest risk of AMI was seen in South Asians (men RR = 2.27; 95 % CI 2.08–2.49; women RR = 2.10; 95 % CI 1.76–2.51) while the lowest was seen in East Asians (RR = 0.38 in both men (95 % CI 0.25–0.58) and women (95 % CI 0.18–0.79)). Immigrants from Former Yugoslavia and Central Asia also had increased risk of AMI compared to ethnic Norwegians. South Asians had increased risk of stroke (men RR = 1.26; 95 % CI 1.10–1.44; women RR = 1.58; 95 % CI 1.32–1.90), as did men from Former Yugoslavia, Sub-Saharan Africa and women from Southeast Asia. Preventive measures should be aimed at reducing the excess numbers of CVD among immigrants from South Asia and Former Yugoslavia.

Reduction of salt intake is a public health priority and necessitates the surveillance of salt intake in the population. The validity of salt intake assessed by dietary surveys is generally low. We, therefore, aimed to estimate salt intake by 24-h urine collection and to assess the usefulness of spot urine collection for surveillance purposes. In the population-based Tromsø Study 2015–2016, 493 men and women aged 40–69 years collected 24-h urine, of whom 475 also collected spot urine. Sodium and potassium excretions were calculated by multiplying respective urinary concentrations by the total volume of urine. Based on the sodium concentration in spot urine, we also estimated 24-h sodium excretion by three different equations. Mean sodium excretion was 4.09 ± 1.60 and 2.98 ± 1.09 g/24-h in men and women, respectively, corresponding to a calculated salt intake of 10.4 and 7.6 g. The sodium to potassium molar (Na/K) ratio was approximately 1.8 in both genders. Of the three equation utilizing spot urine, estimated mean 24-h sodium excretion was closest for the INTERSALT formulae (4.29 and 2.96 g/24-h in men and women, respectively). In this population-based study, the estimated salt intake was higher than the recommended intake. However, urine potassium excretion was rather high resulting in a favorable Na/K ratio. Mean sodium excretion calculated from spot urine by the INTERSALT equation predicted the mean sodium excretion in 24-h urine reasonably well.

Norway has a very high incidence of osteoporotic fractures, with substantial regional differences in fracture incidence. The present study evaluated whether there are differences in bone mineral density (BMD) between regions in Norway with differences in fracture incidence. The authors used data collected in four large, population-based, multipurpose studies performed in four regions of Norway during 1994–2001. Distal forearm BMD was measured by single energy x-ray absorptiometry in 10,667 participants aged 40–75 years. Cross-calibration was performed by using the European Forearm Phantom. Mean distal forearm BMD was lower in the urban populations of Tromsø, Oslo, and Bergen compared with the rural county of Nord-Trøndelag, whereas there was no difference between the rural part of Tromsø and Nord-Trøndelag. For women, body mass index explained some of these differences. The prevalence of low BMD (z score ≤ –1) in Oslo, Bergen, and urban Tromsø, compared with Nord-Trøndelag, was 1.6–1.7 times higher in men and 1.5–2.0 times higher in women, whereas no significant difference was found between rural Tromsø and Nord-Trøndelag. In this study, higher BMD was found in rural compared with urban areas of Norway, which might help explain the differences in fracture incidence. There was no apparent north-south gradient in BMD.