Heritability of spinal pain and consequences of spinal pain: a comprehensive genetic epidemiologic analysis using a population-based sample of 15,328 twins ages 20-71 years.

Objective: To assess the relative contribution of genetic and environmental factors to different definitions of spinal pain and consequences of spinal pain.

Methods: The Danish Twin Registry contains detailed survey information on spinal pain and its consequences in twins ages 20-71 years. A classic genetic epidemiologic analysis was performed in order to establish heritability for a number of phenotypes, including location of pain, radiation of pain in the extremities or chest, pain duration, and combinations of pain in >1 spinal area.

The impact of a TSH receptor gene polymorphism on thyroid-related phenotypes in a healthy Danish twin population.

Objectives: The Asp727Glu polymorphism in the TSH receptor (TSHR) gene is associated with serum TSH levels. However, the proportion of genetic variation accounted for by this polymorphism is unknown. In this study, we (1) examined the association of the Asp727Glu polymorphism with thyroid size, serum levels of TSH, thyroid hormones, and thyroid antibodies in 1241 healthy Danish twin individuals and (2) assessed the contribution of the polymorphism to the trait variation and the genetic variance.

Genetic and environmental interrelations between measurements of thyroid function in a healthy Danish twin population.

Serum thyrotropin (TSH), free thyroxine (T4), and free triiodothyronine (T3) levels illustrate the thyroid function set point, but the interrelations between these have never been characterized in detail. The aim of this study was to examine the associations between TSH and thyroid hormone levels in healthy euthyroid twins and to determine the extent to which the same genes influence more than one of these biochemical traits; 1,380 healthy euthyroid Danish twins (284 monozygotic, 286 dizygotic, 120 opposite-sex twin pairs) were recruited. Genetic and environmental associations between thyroid function measurements were examined using quantitative genetic modeling.

Genetic influence on human lifespan and longevity.

There is an intense search for longevity genes in both animal models and humans. Human family studies have indicated that a modest amount of the overall variation in adult lifespan (approximately 20-30%) is accounted for by genetic factors. But it is not known if genetic factors become increasingly important for survival at the oldest ages.

The relative importance of genetic and environmental effects for the early stages of thyroid autoimmunity: a study of healthy Danish twins.

Objective: In euthyroid individuals, autoantibodies to thyroid peroxidase (TPOab) and thyroglobulin (Tgab) are regarded as early markers of thyroid autoimmunity. Family and twin studies suggest that development of thyroid autoantibodies in first-degree relatives of patients with autoimmune thyroid disease is under genetic influence. We aimed to estimate the relative importance of genetic and environmental effects for the presence of thyroid autoantibodies in euthyroid subjects.