Association between lifestyle features and obesity phenotypes in adults from the Basque Country (Spain).

Lifestyle is related to the risk of obesity, but the relationship between different lifestyle features and obesity phenotypes remains unclear. This study analysed the association between different lifestyle features (eating habits, activity, sleep patterns, and tobacco and alcohol consumption), and four obesity phenotypes (overall and abdominal obesity, distribution and percentage of fat). The sample included 521 adults aged between 18 and 70 years. A multiple logistic regression model was used, controlling for sex, age and socioeconomic status. The duration of the main meal was inversely associated with overall and abdominal obesity (p < 0.01) whereas the number of meals was positively associated (p < 0.05). Regular sport practice and duration were negatively associated with all obesity phenotypes (p < 0.01), while watching television showed positive associations. Walking was inversely related to overall and abdominal obesity (p < 0.01), whereas sleep quality was positively associated with both phenotypes. Former smokers showed a positive relationship with both abdominal obesity (p = 0.021) and fat mass distribution (p = 0.002), and the number of cigarettes were positively related with all obesity phenotypes (p < 0.01), except with fat distribution. Alcohol consumption was inversely related with an excessive adiposity (p = 0.030), while occasional drinking was negatively related with overall obesity and an excess of fat. In conclusion, few meals per day, a bad or regular quality of sleep, many hours spent watching television and a heavy cigarette consumption significantly increased the risk of various obesity phenotypes, while time spent at the main meal, walking and sport practice, and a moderate alcohol consumption were associated with a decreased risk.

Ideal body image for the opposite sex and its association with body mass index.

This research studied the preferences reported by women and men about their Ideal Body Image for the Opposite Sex (IBIOS), and its association with body mass index (BMI). It also analysed the preferences of each sex for a woman's ideal body image (W-IBI) and a man's ideal body image (M-IBI). A total of 450 participants aged 18-70 years with different weights were studied. Their IBIOS was assessed using standard figural stimuli. The sample was divided in four groups by sex and age (<45 years; ≥45 years). Sex and age differences in IBIOS, as well as sex differences in the preferences for a woman's ideal body image (W-IBI) and a man's ideal body image (M-IBI), were tested using a non-parametric Mann-Whitney U test. The association between IBIOS and BMI was analysed using Spearman's correlation. In all groups, the most chosen silhouette as IBIOS was number 4. In the under-45 years group, women chose bigger silhouettes for the opposite sex than men did (p<0.05). In this age group women chose as ideal smaller silhouettes for the female body than men did (p<0.01). In addition, women and men in the younger age group and with normal weight chose smaller silhouettes, while those who were overweight or obese selected larger silhouettes (p<0.001). Age was found to be a relevant factor in IBIOS preferences, and in the association between IBIOS and nutritional status as measured by BMI, which was only observed to be significant in the younger age group.

On-campus food purchase behaviors, choice determinants, and opinions on food availability in a Spanish university community.

OBJECTIVE: The aim of this study was to investigate food purchasing behaviors, choice determinants, and opinions about on-campus food availability by a university community and to analyze differences in these aspects between students, education and/or research staff (ERS), and administrative and services staff (ASS), and between males and females. METHODS: This was a cross-sectional study that involved a representative sample of students (n = 1089), ERS (n = 396), and ASS (n = 300) who completed an anonymous online survey. A previously adapted version of the questionnaire was administered. The results were weighted to ensure representativeness of this community population using weighted coefficients. RESULTS: The results showed that most of the participants purchased food on campus (91.6%), especially for lunch (67.4% of foods and 37.4% of drinks) and snack (65.4% of foods and 45.4% of drinks). Hot drinks (i.e., coffee, tea, hot chocolate etc.; 60.5%), bottled water (49.2%), and hot foods (i.e., small servings [38.2%] and sandwiches/hamburgers [31.7%]) were the most purchased items. Taste (98.6%) was the most important determinant in choice, followed by price for students, nutritional value for ASS, and health value for ERS. The "top 5" opinions suggested for the campus food environment and potential changes were "greater capacity to access free filtered drinking water", "greater capacity to recycle food packaging," "more healthy options in vending machines", "discounts for healthy choices," and "allergen labeling." CONCLUSION: Interventions that improve sustainability and the affordability of products with high nutritional quality, price-manipulation directives, and allergen information on labeling would be well received among this community.

Smoking remains associated with education after controlling for social background and genetic factors in a study of 18 twin cohorts.

We tested the causality between education and smoking using the natural experiment of discordant twin pairs allowing to optimally control for background genetic and childhood social factors. Data from 18 cohorts including 10,527 monozygotic (MZ) and same-sex dizygotic (DZ) twin pairs discordant for education and smoking were analyzed by linear fixed effects regression models. Within twin pairs, education levels were lower among the currently smoking than among the never smoking co-twins and this education difference was larger within DZ than MZ pairs. Similarly, education levels were higher among former smoking than among currently smoking co-twins, and this difference was larger within DZ pairs. Our results support the hypothesis of a causal effect of education on both current smoking status and smoking cessation. However, the even greater intra-pair differences within DZ pairs, who share only 50% of their segregating genes, provide evidence that shared genetic factors also contribute to these associations.

Nutritional quality and carbon footprint of university students' diets: results from the EHU12/24 study.

OBJECTIVE: To evaluate diets in terms of nutritional characteristics and quality from the perspectives of health, greenhouse gas emissions (GHGE) and possible associations with each other in a representative sample of students at a public university. DESIGN: Cross-sectional. Dietary intake was evaluated with a validated FFQ, and diet quality was assessed through the Healthy Eating Index (HEI-2010) and MedDietScore (MDS). GHGE data were obtained from the literature. In addition, sex, socio-economic status (SES) and body fat (BF) status were analysed as covariates. SETTING: Basque Autonomous Community, Spain. PARTICIPANTS: Totally, 26 165 healthy adults aged 18-28 years. RESULTS: Student diets were characterised by low consumption of carbohydrates (38·72 % of total energy intake (TEI)) and a high intake of lipids (39·08 % of TEI). Over half of the participants had low dietary quality. The low-emitting diets were more likely to be consumed by subjects with low HEI-2010 scores (ß: 0·039 kg eCO2/1000 kcal/d) and high MDS scores (ß: -0·023 kg eCO2/1000 kcal/d), after controlling for sex, SES and BF status. Both the low-emitting and healthy diets were more likely to be consumed by women and by those with normal BF percentage. CONCLUSIONS: UPV/EHU university students' diets were characterised by moderate quality from a nutritional perspective and moderate variation in the size of carbon footprints. In this population, diets of the highest quality were not always those with the lowest diet-related GHGE; this relationship depended in part on the constructs and scoring criteria of diet quality indices used.

Educational attainment of same-sex and opposite-sex dizygotic twins: An individual-level pooled study of 19 twin cohorts.

Comparing twins from same- and opposite-sex pairs can provide information on potential sex differences in a variety of outcomes, including socioeconomic-related outcomes such as educational attainment. It has been suggested that this design can be applied to examine the putative role of intrauterine exposure to testosterone for educational attainment, but the evidence is still disputed. Thus, we established an international database of twin data from 11 countries with 88,290 individual dizygotic twins born over 100 years and tested for differences between twins from same- and opposite-sex dizygotic pairs in educational attainment. Effect sizes with 95% confidence intervals (CI) were estimated by linear regression models after adjusting for birth year and twin study cohort. In contrast to the hypothesis, no difference was found in women (ß = -0.05 educational years, 95% CI -0.11, 0.02). However, men with a same-sex co-twin were slightly more educated than men having an opposite-sex co-twin (ß = 0.14 educational years, 95% CI 0.07, 0.21). No consistent differences in effect sizes were found between individual twin study cohorts representing Europe, the USA, and Australia or over the cohorts born during the 20th century, during which period the sex differences in education reversed favoring women in the latest birth cohorts. Further, no interaction was found with maternal or paternal education. Our results contradict the hypothesis that there would be differences in the intrauterine testosterone levels between same-sex and opposite-sex female twins affecting education. Our findings in men may point to social dynamics within same-sex twin pairs that may benefit men in their educational careers.

Phenotypic diversity and history of the Congo Basin populations: Equatorial Guinea, Bantu Speaking Central Africans and African Pygmies.

BACKGROUND: African Pygmy Populations (APP) are believed to be one of the first groups of the Congo Basin rainforest peoples to separate from the rest of modern humanity. The arrival of Bantu speaking agriculturalists from 5,000 BP led to the formation of a large number of ethnic complexes in Central Africa and the Atlantic coastal area, mainly due to a one-way flow of pygmy women. There are now only a few small contingents of African Pygmy population groups who are mixed or who have almost disappeared as a result of migratory flows from Cameroon. AIMS: We analysed the adult phenotypic diversity of 9 populations (17 groups of both sexes) of the Congo basin and Bioko Island, which were anthropometrically characterised in 1948. The phenotypic clusters that we detected, which we interpret as likely mixing of local Pygmy populations and Bantus, may be useful as references for future studies, particularly genetics. SUBJECTS AND METHODS: The matrix of inter-distances between populations was generated, using the 21 variables, with the Euclidean distance between the mean vectors relating to the standardised variables. When the UPGMA (Unweighted Pair Group Method with Arithmetic Mean) was used separately in men and women, the phylogenetic trees showed a clear separation between populations. RESULTS: The body measurements that most effectively distinguished the groups are linear dimensions and the width of the hips and mean thoracic circumference. In this study, the cephalo-facial dimensions were of little value in identifying the groups. CONCLUSIONS: The samples of Equatorial Guinea show a major inter-group overlap, and considerable intra-group variations. There are also notable differences amongst African Pygmy populations in terms of height, but not in body proportions.

Association between self-perceived body image and body composition between the sexes and different age classes.

OBJECTIVES: The aim of this study was to investigate the association between self-perceived body image and body composition in the sexes and in different age classes. METHODS: The sample consisted of 632 young adults (238 men and 394 women; 22.8 ± 2.3 y of age), and 162 middle-aged and elderly adults (96 men and 66 women; 61.4 ± 7.6 y of age). The Williamson's figure scale was used to evaluate current body size. Anthropometric measurements (height, weight and waist, arm and calf circumferences) were taken, and body mass index was calculated. Specific bioelectrical impedance vector analysis was applied to evaluate body composition. RESULTS: The findings suggest that in both age classes, current body size was positively correlated with weight, body mass index, and vector length, indicative of the percentage of fat mass, but not with phase angle, indicative of the intracellular/extracellular water ratio and a proxy of muscle mass. The association was similar between men and women, but clearer in women. Confidence ellipses confirmed the strong association between the silhouettes and adiposity. CONCLUSION: The Williamson's figure scale silhouettes appear to be a suitable technique to screen for adiposity in epidemiologic studies and for routine applications.

Genetic and environmental variation in educational attainment: an individual-based analysis of 28 twin cohorts.

We investigated the heritability of educational attainment and how it differed between birth cohorts and cultural-geographic regions. A classical twin design was applied to pooled data from 28 cohorts representing 16 countries and including 193,518 twins with information on educational attainment at 25 years of age or older. Genetic factors explained the major part of individual differences in educational attainment (heritability: a2 = 0.43; 0.41-0.44), but also environmental variation shared by co-twins was substantial (c2 = 0.31; 0.30-0.33). The proportions of educational variation explained by genetic and shared environmental factors did not differ between Europe, North America and Australia, and East Asia. When restricted to twins 30 years or older to confirm finalized education, the heritability was higher in the older cohorts born in 1900-1949 (a2 = 0.44; 0.41-0.46) than in the later cohorts born in 1950-1989 (a2 = 0.38; 0.36-0.40), with a corresponding lower influence of common environmental factors (c2 = 0.31; 0.29-0.33 and c2 = 0.34; 0.32-0.36, respectively). In conclusion, both genetic and environmental factors shared by co-twins have an important influence on individual differences in educational attainment. The effect of genetic factors on educational attainment has decreased from the cohorts born before to those born after the 1950s.

Genetic and environmental influences on human height from infancy through adulthood at different levels of parental education.

Genetic factors explain a major proportion of human height variation, but differences in mean stature have also been found between socio-economic categories suggesting a possible effect of environment. By utilizing a classical twin design which allows decomposing the variation of height into genetic and environmental components, we tested the hypothesis that environmental variation in height is greater in offspring of lower educated parents. Twin data from 29 cohorts including 65,978 complete twin pairs with information on height at ages 1 to 69 years and on parental education were pooled allowing the analyses at different ages and in three geographic-cultural regions (Europe, North America and Australia, and East Asia). Parental education mostly showed a positive association with offspring height, with significant associations in mid-childhood and from adolescence onwards. In variance decomposition modeling, the genetic and environmental variance components of height did not show a consistent relation to parental education. A random-effects meta-regression analysis of the aggregate-level data showed a trend towards greater shared environmental variation of height in low parental education families. In conclusion, in our very large dataset from twin cohorts around the globe, these results provide only weak evidence for the study hypothesis.

Body image in relation to nutritional status in adults from the Basque Country, Spain.

The aim of this research was to analyse variation in body image perception and satisfaction by age, sex and nutritional status in an adult sample from the Basque Country, Spain. A case-control study was performed for 227 women and 178 men aged 18-70 years. Stunkard's silhouettes were used to evaluate Current Body Image (CBI) and Ideal Body Image (IBI), as well as dissatisfaction and inconsistency scores. Nutritional status was assessed following the WHO criteria for BMI in an adult population. The sample was divided into four groups based on sex and age (early adulthood <45 years, and middle/older adulthood ≥45 years). The Mann-Whitney U test was employed to evaluate sex and age differences, and the Gamma coefficient to assess the association between body image variables and nutritional status. Significant age differences in CBI (p<0.05) and sex differences in IBI (p<0.001) were detected. Both variables showed a positive association with BMI (p<0.01), which indicates that BMI is a biological characteristic related to body image satisfaction and influences participants' perception of themselves. Dissatisfaction scores showed that both sex and age differences (p<0.05) were negatively associated with BMI (p<0.001). Only participants ≥45 years presented sex differences in inconsistency scores (p<0.05); this variable was associated with BMI in women (p<0.01). Preferences in body image showed sexual dimorphism, with women preferring thinner bodies than men - a pattern observed in many Western populations - linked in part to sociocultural pressures. Women were more dissatisfied with their bodies than men; a higher dissatisfaction was observed in older relative to younger participants. The results confirm the association between nutritional status and body size perception and satisfaction, but also the relationship between nutritional status and the reliability with which women can classify themselves; in men, this relationship was not as clear.

European Roma groups show complex West Eurasian admixture footprints and a common South Asian genetic origin.

The Roma population is the largest transnational ethnic minority in Europe, characterized by a linguistic, cultural and historical heterogeneity. Comparative linguistics and genetic studies have placed the origin of European Roma in the Northwest of India. After their migration across Persia, they entered into the Balkan Peninsula, from where they spread into Europe, arriving in the Iberian Peninsula in the 15th century. Their particular demographic history has genetic implications linked to rare and common diseases. However, the South Asian source of the proto-Roma remains still untargeted and the West Eurasian Roma component has not been yet deeply characterized. Here, in order to describe both the South Asian and West Eurasian ancestries, we analyze previously published genome-wide data of 152 European Roma and 34 new Iberian Roma samples at a fine-scale and haplotype-based level, with special focus on the Iberian Roma genetic substructure. Our results suggest that the putative origin of the proto-Roma involves a Punjabi group with low levels of West Eurasian ancestry. In addition, we have identified a complex West Eurasian component (around 65%) in the Roma, as a result of the admixture events occurred with non-proto-Roma populations between 1270-1580. Particularly, we have detected the Balkan genetic footprint in all European Roma, and the Baltic and Iberian components in the Northern and Western Roma groups, respectively. Finally, our results show genetic substructure within the Iberian Roma, with different levels of West Eurasian admixture, as a result of the complex historical events occurred in the Peninsula.

Parental Education and Genetics of BMI from Infancy to Old Age: A Pooled Analysis of 29 Twin Cohorts.

OBJECTIVE: The objective of this study was to analyze how parental education modifies the genetic and environmental variances of BMI from infancy to old age in three geographic-cultural regions. METHODS: A pooled sample of 29 cohorts including 143,499 twin individuals with information on parental education and BMI from age 1 to 79 years (299,201 BMI measures) was analyzed by genetic twin modeling. RESULTS: Until 4 years of age, parental education was not consistently associated with BMI. Thereafter, higher parental education level was associated with lower BMI in males and females. Total and additive genetic variances of BMI were smaller in the offspring of highly educated parents than in those whose parents had low education levels. Especially in North American and Australian children, environmental factors shared by co-twins also contributed to the higher BMI variation in the low education level category. In Europe and East Asia, the associations of parental education with mean BMI and BMI variance were weaker than in North America and Australia. CONCLUSIONS: Lower parental education level is associated with higher mean BMI and larger genetic variance of BMI after early childhood, especially in the obesogenic macro-environment. The interplay among genetic predisposition, childhood social environment, and macro-social context is important for socioeconomic differences in BMI.

Contribution of obesity associated genetic variants to anthropometric somatotype components.

The somatotype is a useful method in the analysis of body morphology but no study has identified genetic variants associated with its components. The aim of this study is o replicate the association of 21 SNPs with obesity and to explore their association with the somatotype components, in a sample from the Basque Country (Spain). A case-control study was performed in 472 adults from 18 to 79 years old. A literature search was conducted in PubMed to select genetic variants associated with obesity in European derived populations. After the quality control of the chosen variants, 21 SNPs were finally used to conduct association analyses. Logistic and linear regressions implemented in PLINK (v1.07) were used to assess the association between SNPs and the somatotype. Two genetic variants (rs925946 in BDNF and rs10146997 in NRXN3) showed a significant association with endomorphy (p < 0.01) while rs10146997 (in NRXN3) and rs9939609 (in FTO) were associated with mesomorphy (p < 0.01). rs925946 (in BDNF), rs10146997 (in NRXN3), rs9939609 (in FTO) and rs4776970 (in MAP2K5) were associated with ectomorphy (p < 0.05). In conclusion, four genetic variants (in or near BDNF, NRXN3, MAP2K5 and FTO) contribute to body shape and composition in the analysed sample.

Association of current and former smoking with body mass index: A study of smoking discordant twin pairs from 21 twin cohorts.

BACKGROUND: Smokers tend to weigh less than never smokers, while successful quitting leads to an increase in body weight. Because smokers and non-smokers may differ in genetic and environmental family background, we analysed data from twin pairs in which the co-twins differed by their smoking behaviour to evaluate if the association between smoking and body mass index (BMI) remains after controlling for family background. METHODS AND FINDINGS: The international CODATwins database includes information on smoking and BMI measured between 1960 and 2012 from 156,593 twin individuals 18-69 years of age. Individual-based data (230,378 measurements) and data of smoking discordant twin pairs (altogether 30,014 pairwise measurements, 36% from monozygotic [MZ] pairs) were analysed with linear fixed-effects regression models by 10-year periods. In MZ pairs, the smoking co-twin had, on average, 0.57 kg/m2 lower BMI in men (95% confidence interval (CI): 0.49, 0.70) and 0.65 kg/m2 lower BMI in women (95% CI: 0.52, 0.79) than the never smoking co-twin. Former smokers had 0.70 kg/m2 higher BMI among men (95% CI: 0.63, 0.78) and 0.62 kg/m2 higher BMI among women (95% CI: 0.51, 0.73) than their currently smoking MZ co-twins. Little difference in BMI was observed when comparing former smoking co-twins with their never smoking MZ co-twins (0.13 kg/m2, 95% CI 0.04, 0.23 among men; -0.04 kg/m2, 95% CI -0.16, 0.09 among women). The associations were similar within dizygotic pairs and when analysing twins as individuals. The observed series of cross-sectional associations were independent of sex, age, and measurement decade. CONCLUSIONS: Smoking is associated with lower BMI and smoking cessation with higher BMI. However, the net effect of smoking and subsequent cessation on weight development appears to be minimal, i.e. never more than an average of 0.7 kg/m2.

Association between birth weight and educational attainment: an individual-based pooled analysis of nine twin cohorts.

BACKGROUND: There is evidence that birth weight is positively associated with education, but it remains unclear whether this association is explained by familial environmental factors, genetic factors or the intrauterine environment. We analysed the association between birth weight and educational years within twin pairs, which controls for genetic factors and the environment shared between co-twins. METHODS: The data were derived from nine twin cohorts in eight countries including 6116 complete twin pairs. The association between birth weight and educational attainment was analysed both between individuals and within pairs using linear regression analyses. RESULTS: In between-individual analyses, birth weight was not associated with educational years. Within-pairs analyses revealed positive but modest associations for some sex, zygosity and birth year groups. The greatest association was found in dizygotic (DZ) men (0.65 educational years/kg birth weight, p=0.006); smaller effects of 0.3 educational years/kg birth weight were found within monozygotic (MZ) twins of both sexes and opposite-sex DZ twins. The magnitude of the associations differed by birth year in MZ women and opposite-sex DZ twins, showing a positive association in the 1915-1959 birth cohort but no association in the 1960-1984 birth cohort. CONCLUSION: Although associations are weak and somewhat inconsistent, our results suggest that intrauterine environment may play a role when explaining the association between birth weight and educational attainment.

Genetic and environmental factors affecting birth size variation: a pooled individual-based analysis of secular trends and global geographical differences using 26 twin cohorts.

Background: The genetic architecture of birth size may differ geographically and over time. We examined differences in the genetic and environmental contributions to birthweight, length and ponderal index (PI) across geographical-cultural regions (Europe, North America and Australia, and East Asia) and across birth cohorts, and how gestational age modifies these effects. Methods: Data from 26 twin cohorts in 16 countries including 57 613 monozygotic and dizygotic twin pairs were pooled. Genetic and environmental variations of birth size were estimated using genetic structural equation modelling. Results: The variance of birthweight and length was predominantly explained by shared environmental factors, whereas the variance of PI was explained both by shared and unique environmental factors. Genetic variance contributing to birth size was small. Adjusting for gestational age decreased the proportions of shared environmental variance and increased the propositions of unique environmental variance. Genetic variance was similar in the geographical-cultural regions, but shared environmental variance was smaller in East Asia than in Europe and North America and Australia. The total variance and shared environmental variance of birth length and PI were greater from the birth cohort 1990-99 onwards compared with the birth cohorts from 1970-79 to 1980-89. Conclusions: The contribution of genetic factors to birth size is smaller than that of shared environmental factors, which is partly explained by gestational age. Shared environmental variances of birth length and PI were greater in the latest birth cohorts and differed also across geographical-cultural regions. Shared environmental factors are important when explaining differences in the variation of birth size globally and over time.

Birth size and gestational age in opposite-sex twins as compared to same-sex twins: An individual-based pooled analysis of 21 cohorts.

It is well established that boys are born heavier and longer than girls, but it remains unclear whether birth size in twins is affected by the sex of their co-twin. We conducted an individual-based pooled analysis of 21 twin cohorts in 15 countries derived from the COllaborative project of Development of Anthropometrical measures in Twins (CODATwins), including 67,850 dizygotic twin individuals. Linear regression analyses showed that boys having a co-twin sister were, on average, 31 g (95% CI 18 to 45) heavier and 0.16 cm (95% CI 0.045 to 0.274) longer than those with a co-twin brother. In girls, birth size was not associated (5 g birth weight; 95% CI -8 to -18 and -0.089 cm birth length; 95% CI -0.202 to 0.025) with the sex of the co-twin. Gestational age was slightly shorter in boy-boy pairs than in boy-girl and girl-girl pairs. When birth size was standardized by gestational age, the magnitude of the associations was attenuated in boys, particularly for birth weight. In conclusion, boys with a co-twin sister are heavier and longer at birth than those with a co-twin brother. However, these differences are modest and partly explained by a longer gestation in the presence of a co-twin sister.

Tau haplotypes support the Asian ancestry of the Roma population settled in the Basque Country.

We examined tau haplotype frequencies in two different ethnical groups from the Basque Country (BC): Roma people and residents of European ancestry (general population). In addition, we analyzed the spatial distribution of tau haplotypes in Eurasian populations to explore the genetic affinities of the Romani groups living in Europe in a broader scope. The 17q21.31 genomic region was characterized through the genotyping of two diagnostic single nucleotide polymorphisms, SNPs (rs10514879 and rs199451), which allow the identification of H1 and H2 haplotypes. A significant heterozygous deficit was detected in the Romani for rs10514879. The H2 haplotype frequency proved to be more than twice in the BC general population (0.283) than in the Roma people (0.127). In contrast, H2 frequency proved to be very similar between Basque and Hungarian Romani, and similar to the H2 frequencies found in northwestern India and Pakistan as well. Several statistical analyses unveiled genetic structuring for the MAPT diversity, mirrored in a significant association between geography and genetic distances, with an upward trend of H2 haplotype frequencies from Asia to Europe. Yet, Roma samples did not fit into this general spatial patterning because of their discrepancy between geographical position and H2 frequency. Despite the long spatial coexistence in the Basque region between the residents of European ancestry and the Roma, the latter have preserved their Asian genetic ancestry. Bearing in mind the lack of geographical barriers between both ethnical groups, these findings support the notion that sociocultural mores might promote assortative matings in human populations.

Effect of ewe's (semi-skimmed and whole) and cow's milk yogurt consumption on the lipid profile of control subjects: a crossover study.

Yogurt is the most widely consumed fermented milk product worldwide. Studies have mainly used milk and dairy products from cow, which have a lower fat content than those from ewe and a different lipid profile. This study investigated the effect on the lipid profile of control subjects of three different set yogurts: (a) semi-skimmed ewe´s milk yogurt (2.8% milk fat); (b) whole ewe´s milk yogurt (5.8 % milk fat); (c) cow´s milk yogurt (3 % milk fat). A randomized crossover study included 30 healthy adults (16 women) to consume 250 g/yogurt/day during three consecutive 5-weeks periods separated by 4-week washouts. Blood samples were collected at the start and end of each period for the analysis of serum cholesterol (total, HDL-, LDL-) and triglycerides. We found no differences in the serum concentrations of lipid and lipoprotein fractions of the volunteers after the intake of any of the three types of yogurts. When the volunteers were grouped into two risk groups of risk according to their total cholesterol/HDL cholesterol ratio, the same differences between the groups in terms of the cholesterol (HDL-, LDL-) and triglyceride responses at baseline and after yogurt intake were found, with no effects due to the different types of yogurts. Moreover, we performed compositional analysis of the yogurts including determination of protein, fat, minerals and fatty acids (FA). Contents in protein, calcium, magnesium, non-protein nitrogen and some FA (mainly short-chain-FA) were higher for ewe's than for cow's milk yogurt. n6-n3 ratio was lower in the ewe's milk yogurt. In conclusion, yogurt intake, from ewe's and cow's milk, at levels of consumption compatible with a varied diet, neither decreases nor increases plasma lipoprotein cholesterol levels in apparently healthy individuals. As ewe's milk yogurt has a high content of macro- and micronutrients, certain target populations could benefit from its consumption.