Inference of the genetic architecture underlying BMI and height with the use of 20,240 sibling pairs

Evidence that complex traits are highly polygenic has been presented by population-based genome-wide association studies (GWASs) through the identification of many significant variants, as well as by family-based de novo sequencing studies indicating that several traits have a large mutational target size. Here, using a third study design, we show results consistent with extreme polygenicity for body mass index (BMI) and height. On a sample of 20,240 siblings (from 9,570 nuclear families), we used a within-family method to obtain narrow-sense heritability estimates of 0.42 (SE = 0.17, p = 0.01) and 0.69 (SE = 0.14, p = 6 x 10(-)(7)) for BMI and height, respectively, after adjusting for covariates. The genomic inflation factors from locus-specific linkage analysis were 1.69 (SE = 0.21, p = 0.04) for BMI and 2.18 (SE = 0.21, p = 2 x 10(-10)) for height. This inflation is free of confounding and congruent with polygenicity, consistent with observations of ever-increasing genomic-inflation factors from GWASs with large sample sizes, implying that those signals are due to true genetic signals across the genome rather than population stratification. We also demonstrate that the distribution of the observed test statistics is consistent with both rare and common variants underlying a polygenic architecture and that previous reports of linkage signals in complex traits are probably a consequence of polygenic architecture rather than the segregation of variants with large effects. The convergent empirical evidence from GWASs, de novo studies, and within-family segregation implies that family-based sequencing studies for complex traits require very large sample sizes because the effects of causal variants are small on average.

Exterior view of the Boehm family hat factory; Novy Jicin, Czech Republic Businesses

Tovarna na Klobouky Fv. Boehm

Erich Gustav Baum in the drivers seat of a car with his wife Grete nee Dublon and their daughter Ilse Baum in the back seat Portraits Family

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Ilse Baum's class portrait Portraits Family

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View of Muensterstrasse including Erich Gustav Baum's haberdashery store (Waesche Baum); Rheine i.W. Portraits Family

The shop was shut down by the Nazis several times during the 1930s

Grete Baum nee Dublon assisting a customer in her husband Erich Gustav Baum's haberdashery store (Waesche Baum); Muensterstrasse, Rheine i.W. Portraits Family

The shop was shut down by the Nazis several times during the 1930s

Portrait of the six Baum family siblings Portraits Family

Standing are Fritz, Joseph and Lilly. The youngest is Hans. Erich is seated center and Walter is seated on the far right.

Fanny and Hugo Eichenwald with two of their three children, Fritz and Hanne outside of their home; Rheine Portraits; Family

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The three Eichenwald children, Fritz, Hanne and Hans Portraits; Family

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Isidor Simon seated at an outdoor table with his wife Friederike nee Falkenburg and two grandchildren, Helmuth and Walther Simon Portraits Family

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Kisch family portrait; Alexander, Mizzi, Charlotte, Guido and Bruno (l-r); Prague.

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Reproduction of photograph of Kaufman and Rosenberg family portrait on the occasion of the wedding of Ludwig Rosenberg and Paula Rosenberg nee Joseph (left); Hamburg.

Includes Ludwig Rosenberg and Paula Rosenberg nee Joseph (left), Thekla (Tekie) Joseph (standing center), Karl Kaufman and Else Kaufman (right)

Inpatient hospital care and its costs among type 1 diabetic patients in Finland : a nationwide longitudinal study

Background. In Finland, the incidence of type 1 diabetes mellitus (T1DM) is the highest in the world, and it continues to increase steadily. No effective preventative interventions exist either for individuals at high risk or for the population as a whole. In addition to problems with daily lifelong insulin replacement therapy, T1DM patients with long-lasting disease suffer from various diabetes related complications. The complications can lead to severe impairments and reductions in functional capacity and quality of life and in the worst case they can be fatal. Longitudinal studies on the costs of T1DM are extremely rare, especially in Finland. Typically, in these studies, distinctions between the various types of diabetes have not been made, and costs have not been calculated separately for the sexes. Aims. The aim of this study was to describe inpatient hospital care and costs of inpatient care in a cohort of 5,166 T1DM patients by sex during 1973-1998 in Finland. Inpatient care and costs of care due to T1DM without complications, due to T1DM with complications and due to other causes were calculated separately. Material and Methods. The study population consisted of all Finnish T1DM patients diagnosed before the age of 18 years between January 1st in 1965 and December 31st in 1979 and derived from the Finnish population based T1DM register (N=5,120 in 1979 and N=4,701 in 1997). Data on hospitalisations were obtained from the Finnish Hospital Discharge Register. Results. In the early stages of T1DM, the majority of the use of inpatient care was due to the treatment of T1DM without complications. There were enormous increases in the use of inpatient care for certain complications when T1DM lasted longer (from 9.5 years to 16.5 years). For women, the yearly number of bed-days for renal complications increased 4.8-fold, for peripheral vascular disease 4.3-fold and for ophthalmic complications 2.5-fold. For men, the corresponding increases were as follows: 5-fold, 6.9-fold and 2.5-fold. The yearly bed-days for glaucoma increased 8-fold, nephropathy 7-fold and microangiopathy 6-fold in the total population. During these 7 years, the yearly numbers of bed-days for T1DM without complications dropped dramatically. The length of stay in inpatient care decreased notably, but hospital visits became more frequent when the length of duration of T1DM increased from 9.5 years to 16.5 years. The costs of treatments due to complications increased when T1DM lasted longer. Costs due to inpatient care of complications in the cohort 2.5-folded as duration of T1DM increased from 9.5 years to 16.5 years, while the total costs of inpatient care in the cohort dropped by 22% due to an 80% decrease in the costs of care of T1DM without complications. Treating complications of female patients was more expensive than treating complications of men when T1DM had lasted 9.5 years; the mean annual costs for inpatient care of a female diabetic (any cause) were 1,642 , and the yearly costs of care of complications were 237 . The corresponding yearly mean costs for a male patient were 1,198 and 167 . Treating complications of female patients was more expensive than that of male patients also when the duration of diabetes was 16.5 years, although the difference in average annual costs between sexes was somewhat smaller. Conclusions. In the early phases of T1DM, the treatment of T1DM without complications causes a considerable amount of hospital bed-days. The use of inpatient care due to complications of T1DM strongly increases with ageing of patients. The economic burden of inpatient care of T1DM is substantial.