Low maternal vitamin D status during pregnancy may have negative consequences for both mother and child. There are few studies of vitamin D status and its determinants in pregnant women living at northern latitudes. Thus, the present study investigates vitamin D status and its determinants during the third trimester of women living in Sweden (latitudes 57-58°N). A total of ninety-five fair-skinned pregnant women had blood taken between gestational weeks 35 and 37. The study included a 4 d food diary and questionnaires on dietary intake, supplement use, sun exposure, skin type, travels to southern latitudes and measure of BMI. Serum 25-hydroxyvitamin D (25(OH)D) was analysed using the chemiluminescence immunoassay. In the third trimester of pregnancy, mean serum concentration of 25(OH)D was 47.4 (sd 18.1) nmol/l (range 10-93 nmol/l). In total, 65% of women had serum 25(OH)D
Colour changes in two salmonid fish, the salmon (Salmo salar) and sea trout (S. trutta), were examined in relation to infection with the trematode Diplostomum spathaceum. This parasite had no effect on the rate of colour change in these fish, although species specific differences in colour adjustment times were observed. Increasing asymmetry in parasite numbers between the right and left eye, which could lead to the retention of vision in one eye, nevertheless tended to reduce the colour change time in salmon with moderate infection (P=0.08). This first experimental attempt to examine colour changes in fish in relation to eye fluke infections provides grounds for future investigations. The darker appearance of the heavily infected fish described in the literature suggests that a high parasite burden actually causes colour changes. We emphasise that detailed quantitative studies using fish with higher parasite loads, especially from the tail of the aggregated parasite distribution, are needed to describe these relationships in detail.
The yellow colour of the skin was measured just after birth in 100 mature newborns using a jaundice meter. The skin colour was significantly correlated to the cord bilirubin concentration (rho = 0.26, p = 0.009), but unrelated to cord reserve albumin concentration, cord albumin concentration, cord haemoglobin concentration, birth weight and gestational age. In 123 other mature newborns, the basal yellow colour of the skin was estimated on the basis of meter readings taken just after birth. Correction of meter readings taken on the third postnatal day for the basal yellow skin colour improved neither the correlation between the meter readings and the bilirubin concentration nor the ability of the meter readings to predict hyperbilirubinaemia.
Eye colour, hair colour and skin colour are important risk factors for malignant melanoma and non-melanoma skin cancers. There are few studies in which the distribution of these pigmentary factors in risk populations has been assessed. The purpose of this study was to investigate the prevalence of the major eye and hair colours and the distribution of skin types and skin pigmentation in a Caucasian population. In 892 Danish Caucasians, eye colour, hair colour and skin type were assessed and facultative and constitutive skin pigmentation were measured objectively using skin reflectance spectroscopy. Blue eye colour and blond hair colour and skin type II were the most frequent (60%, 67% and 33% of subjects, respectively). All four major eye colours and four major hair colours (with the exception of red hair colour) were found within skin types I-IV and we could not predict the skin type or the constitutive skin pigmentation. Skin type could not be taken to classify individuals reliably according to their facultative or constitutive skin pigmentation.
The population is increasingly lighter pigmented moving in a northward direction in Europe until reaching the Arctic Circle, where the Samis (Lapps) are clearly more pigmented.
In 1966-1970, we investigated a total of 689 subjects in the villages of Sevettijärvi and Nellim, including persons with mixed Sami and Finnish heritage; of these, 487 (242 males, 245 females) had both parents classified as Skolt Sami. For estimation of the colour of the iris and hair, international scales were used. For translucency of the iris, pigmentation of the fundus was estimated in 3 different shades. The length and type of eyelashes were classified into 3 categories. To our knowledge, a simultaneous study of the pigmentation of eyebrows, eyelashes and eye fundus at different ages has not previously been published.
The age differences of iris colour were highly significant. Iris colour in children varied markedly, and they generally had lighter colours than later in life. Age and sex effects on the translucency of irises were found. Male irises were more translucent. Fundus pigmentation was scanty in the youngest age groups, with full pigmentation being reached at 20 years. Among young individuals hair colour darkens with increasing age. Eyebrow colour was slightly lighter for both sexes in the youngest age groups that in older cohorts. Women had longer eyelashes than males.
The main factor of the lighter skin is a higher ability to synthesize vitamin D, providing superior protection against rickets. The Skolt Samis are more pigmented than other Nordic people. In earlier times they had problems with rickets but our studies did not show any essential symptoms of rickets today. Visual acuity among Skolt Samis was good. They had lower prevalence of myopia compared to Finns. The stronger pigmentation of Skolt Samis is probably due to their origin from darker Eastern populations. Since our investigations were made, the Skolt Samis have been to a great part mixed with neighbouring populations and scattered throughout Finland. Even their old language is nowadays used mainly for traditional purposes. Therefore similar studies could not be performed anymore.
Sunscreen is recommended to prevent sunburn and skin cancer.
To investigate sunscreen use in relation to demographic and phenotypic characteristics among women in Norway, as well as solar UV exposure, sunburn experience in different decades of life, and temporal trends in sunscreen use.
We used data from the Norwegian Women and Cancer Study, a large population-based prospective cohort study. Log-binomial regression was used to estimate the association between sunscreen use and personal characteristics. Results are presented as prevalence ratios (PRs) and 99% confidence intervals (CIs).
The study sample consisted of 148,869 women, with a mean age, when answering the questionnaire, of 53 years (range 41-75). Sixty-five per cent of the women used sunscreen during the Easter holiday, 73% in northern latitudes and 87% in bathing vacations in southern latitudes. Sunscreen with sun protection factor (SPF) = 15 was used by 25,156 (18%) at Easter, 18,118 (13%) in northern latitudes and 22,678 (30%) in southern latitudes. The prevalence of sunscreen use increased from 1997 to 2007, and this increase was associated with age. In 1997, 39% of women reported at least one sunburn per year in the recent decade, compared with 46% in 2007 (Ptrend = 0·001). Women who experienced at least four sunburns per year during adolescence reported more sunscreen use in adulthood (PREaster 1·54, 99% CI 1·30-1·83; PRnorthern latitudes 1·49, 99% CI 1·20-1·84; PRsouthern latitudes 1·37, 99% CI 1·14-1·65).
The prevalence of sunscreen use increased from 1997 to 2007. However, this increase has not been accompanied by a decrease in sunburn. Moreover, use of sunscreen with the recommended SPF was not common among Norwegian women.
Multiple exposures to ultraviolet radiation (UVR) are the norm in nature and phototherapy. However, studies of the kinetics of pigmentation following UVA exposure have included only fair-skinned persons. The aim of this study was to investigate steady-state pigmentation and fading in 12 Scandinavians and 12 Indians/Pakistanis after 6 and 12 exposures on the back using broadband UVA and UVA1 with equal sub-minimal melanogenic doses (individually predetermined). Pigmentation was measured by skin reflectance at 555 and 660 nm. The UV dose to minimal pigmentation was higher in dark-skinned persons after a single broadband UVA exposure, but independent of pigmentation/skin type after single and multiple UVA1 exposures. To elicit minimal melanogenic doses after 6 and 12 exposures, every dose is lowered by a factor of 2 and 3, respectively, but the cumulative dose increases three- and four-fold, respectively. The absolute increase in pigmentation was independent of pre-exposure pigmentation; therefore the percentage increase in pigmentation was higher in fair-skinned subjects. The absolute increase in pigmentation was higher and it took 2-3 days longer to reach steady-state after 12 UV exposures compared with 6 UV exposures. Days to steady-state pigmentation and fading were independent of pre-exposure pigmentation, and fading took 5-6 months. Comparing data from a narrowband UVB source and a Solar Simulator, it was shown that pigmentation built up faster and increased more after 12 UVA exposures (16 days) than with the Solar Simulator (21 days).