Intergenerational correlations in size at birth and the contribution of environmental factors: The Uppsala Birth Cohort Multigenerational Study, Sweden, 1915-2002.

Sizes at birth of parents and their children are known to be correlated, reflecting in part the influence of fetal and maternal genes. Sociodemographic factors, regarded as aspects of the shared environment across generations, would also be expected to contribute, but evidence is limited. In the present study, the authors aimed to quantify the role of the shared environment in explaining intergenerational correlations in birth weight and length by using data across 3 consecutive generations from the Uppsala Birth Cohort Multigenerational Study in Uppsala, Sweden. That study included birth and sociodemographic data on 7,657 singletons born in Uppsala in 1915-1929 (generation 1) and their grandchildren (generation 3). Standard regression and biometric models were used to study the correlations in size at birth of generation 1-generation 3 pairs. The data showed stronger correlations in maternal pairs than in paternal pairs for birth weight (0.125 vs. 0.096, P = 0.02) but not for birth length (0.097 vs. 0.093, P = 0.77). These correlations were not reduced by adjustment for sociodemographic factors in regression models. In contrast, significant shared-environment contributions to the intergenerational correlations were identified in biometric models, averaging 14% for both birth measures. These models assumed a common latent factor for the sociodemographic variables. The present results show that the shared environment moderately but significantly contributes to intergenerational correlations

Serum Carotenoids and Fat-Soluble Vitamins in Women With Type 1 Diabetes and Preeclampsia: A longitudinal study

OBJECTIVE: Increased oxidative stress and immune dysfunction are implicated in preeclampsia (PE) and may contribute to the two- to fourfold increase in PE prevalence among women with type 1 diabetes. Prospective measures of fat-soluble vitamins in diabetic pregnancy are therefore of interest. RESEARCH DESIGN AND METHODS: Maternal serum carotenoids (α- and β-carotene, lycopene, and lutein) and vitamins A, D, and E (α- and γ-tocopherols) were measured at first (12.2 ± 1.9 weeks [mean ± SD], visit 1), second (21.6 ± 1.5 weeks, visit 2), and third (31.5 ± 1.7 weeks, visit 3) trimesters of pregnancy in 23 women with type 1 diabetes who subsequently developed PE (DM PE+) and 24 women with type 1 diabetes, matched for age, diabetes duration, HbA(1c), and parity, who did not develop PE (DM PE-). Data were analyzed without and with adjustment for baseline differences in BMI, HDL cholesterol, and prandial status. RESULTS: In unadjusted analysis, in DM PE+ versus DM PE-, α-carotene and β-carotene were 45 and 53% lower, respectively, at visit 3 (P < 0.05), before PE onset. In adjusted analyses, the difference in β-carotene at visit 3 remained significant. Most participants were vitamin D deficient (<20 ng/mL), and vitamin D levels were lower in DM PE+ versus DM PE- throughout the pregnancy, although this did not reach statistical significance. CONCLUSIONS: In pregnant women with type 1 diabetes, low serum α- and β-carotene were associated with subsequent development of PE, and vitamin D deficiency may also be implicated

Association of Type 1 Diabetes With Month of Birth Among U.S. Youth: The SEARCH for Diabetes in Youth Study

OBJECTIVE - Seasonal environment at birth may influence diabetes incidence in later life. We sought evidence for this effect in a large sample of diabetic youth residing in the U.S. RESEARCH DESIGN AND METHODS— We compared the distribution of birth months within the SEARCH for Diabetes in Youth Study (SEARCH study) with the monthly distributions in U.S. births tabulated by race for years 1982-2005. SEARCH study participants (9,737 youth with type 1 diabetes and 1,749 with type 2 diabetes) were identified by six collaborating U.S. centers. RESULTS— Among type 1 diabetic youth, the percentage of observed to expected births differed across the months (P = 0.0092; decreased in October-February and increased in March―July). Their smoothed birth-month estimates demonstrated a deficit in November-February births and an excess in April-July births (smoothed May versus January relative risk [RR] = 1.06 [95% CI 1.02―1.11]). Stratifications by sex or by three racial groups showed similar patterns relating type 1 diabetes to month of birth. Stratification by geographic regions showed a peak-to-nadir RR of 1.10 [1.04-1.16] in study regions from the northern latitudes (Colorado, western Washington State, and southern Ohio) but no birth-month effect (P > 0.9) in study regions from more southern locations. Among type 2 diabetic youth, associations with birth month were inconclusive. CONCLUSIONS— Spring births were associated with increased likelihood of type 1 diabetes but possibly not in all U.S. regions. Causal mechanisms may involve factors dependent on geographic latitude such as solar irradiance, but it is unknown whether they influence prenatal or early postnatal development

Polygenic prediction of educational attainment within and between families from genome-wide association analyses in 3 million individuals

We conduct a genome-wide association study (GWAS) of educational attainment (EA) in a sample of ~3 million individuals and identify 3,952 approximately uncorrelated genome-wide-significant single-nucleotide polymorphisms (SNPs). A genome-wide polygenic predictor, or polygenic index (PGI), explains 12-16% of EA variance and contributes to risk prediction for ten diseases. Direct effects (i.e., controlling for parental PGIs) explain roughly half the PGI's magnitude of association with EA and other phenotypes. The correlation between mate-pair PGIs is far too large to be consistent with phenotypic assortment alone, implying additional assortment on PGI-associated factors. In an additional GWAS of dominance deviations from the additive model, we identify no genome-wide-significant SNPs, and a separate X-chromosome additive GWAS identifies 57

Intergenerational learning about keeping health: a qualitative regional Australian study

First published online: December 11, 2012Understanding the conditions under which families try to influence members’ health-related practices can provide information to build concepts adding to models of health promotion. This paper reports on an exploratory qualitative study examining the influences of intergenerational relationships in shaping beliefs, knowledge and practices about health and illness in a regional Australian city. We conducted semi-structured interviews with 27 adults with family members of other generations living in the city, all of whom had experience of asthma. We found that overall people’s experience of health and illness, particularly in childhood, was taken for granted and not reflected upon. It was in the face of serious illness or death of a family member that objective knowledge about health and illness was sought and integrated within the family leading, in most cases, to significant lifestyle changes or ‘doing things differently’. We drew on Bourdieu’s concept of the three forms of theoretical knowledge in analysing our findings. We found the concept of knowledge as ‘primary taken-for-granted experience’, and the concept of praxeological knowledge as the knowledge created by the dialectical relationships between an individual subject and objectives structures were helpful. To influence individual health practices, we need to acknowledge how the family context confirms the taken-for-granted health practices of an individual and the family circumstances that might lead families to seek objective knowledge and make lifestyle changes to promote health.Judy Taylor, Kay Price, Annette Braunack-Mayer, Matthew T. Haren and Robyn McDermot

Serum 25-hydroxyvitamin D, diabetes, and ethnicity in the third national health and nutrition examination survey

OBJECTIVE&mdash; To determine the association between serum 25-hydroxyvitamin D (25OHD) and diabetes risk and whether it varies by ethnicity.RESEARCH DESIGN AND METHODS&mdash; We performed an analysis of data from participants who attended the morning examination of the Third National Health and Nutrition Examination Survey (1988&ndash;1994), a cross-sectional survey of a nationally representative sample of the U.S. population. Serum levels of 25OHD, which reflect vitamin D status, were available from 6,228 people (2,766 non-Hispanic whites, 1,736 non-Hispanic blacks, and 1,726 Mexican Americans) aged &ge;20 years with fasting and/or 2-h plasma glucose and serum insulin measurements.RESULTS&mdash; Adjusting for sex, age, BMI, leisure activity, and quarter of year, ethnicityspecific odds ratios (ORs) for diabetes (fasting glucose &ge;7.0 mmol/l) varied inversely across quartiles of 25OHD in a dose-dependent pattern (OR 0.25 [95% CI 0.11&ndash; 0.60] for non-Hispanic whites and 0.17 [0.08&ndash;0.37] for Mexican Americans) in the highest vitamin D quartile (25OHD &ge;81.0 nmol/l) compared with the lowest 25OHD (&ge;43.9 nmol/l). This inverse associationwas not observed in non-Hispanic blacks. Homeostasis model assessment of insulin resistance (loge) was inversely associated with serum 25OHD in Mexican Americans (P &ge; 0.0024) and non-Hispanic whites (P&ge;0.058) but not non-Hispanic blacks (P&ge;0.93), adjusting for confounders.CONCLUSIONS&mdash; These results show an inverse association between vitamin D status and diabetes, possibly involving insulin resistance, in non-Hispanic whites and Mexican Americans. The lack of an inverse association in non-Hispanic blacks may reflect decreased sensitivity to vitamin D and/or related hormones such as the parathyroid hormone.<br /