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Nancy Pedersen



  • BA (Magna cum Laude), Psychology, University of Minnesota (1974)
  • MA, Psychology, University of Colorado (1977)
  • PhD, Psychology (speciality Behavior Genetics), University of Colorado (1980)

Research description

My research is focused on using twins in the Swedish Twin Registry to:

  • Study the relative importance of genetic and environmental influences on characteristics and diseases
  • Explore how the influence of genes changes over time and with increasing age
  • Test the importance of specific risk and protective factors
  • Test whether there are associations between specific genotypes and diseases or other characteristics
  • Evaluate whether there are interactions between genes and environmental effects

Research projects


Half a million Swedes will be contacted for information concerning their health, lifestyle and exposures, and for donation of blood samples. At the project start (baseline), individuals will be contacted for assessments by age groups. Sampling for blood will be done by LifeGene staff at LifeGene assessment centers and/or in mobile units.

Screening Across the Lifespan Twin study (SALT)

By the end of June, 2002, we had completed a computer-assisted telephone interview of all twins in the Swedish Twin Registry born before 1958. In all, some 45,000 twins were screened concerning most common, complex diseases. Like-sexed pairs in the registry have already responded in the 1960s and 1970s to questionnaires concerning exposures and diseases. Thus, for these twins SALT represents a 30 year follow-up. Information collected during SALT helped us identify sub-samples for in depth studies in which further phenotyping and genotyping were performed. Examples are the Harmony study, the Parkinson's study and TwinGene.

Normal Aging and Age-related Diseases

Since the mid-1980s we have 3 ongoing programs in gerontological genetics: the Swedish Adoption/Twin Study of Aging (SATSA), the OCTO-Twin study of the origins of variance in the oldest-old, and the GENDER study of sex differences in aging. These studies, all of which were designed to address issues of why we age differently, have similar designs and testing instruments. Thus, there are up to 4 waves of longitudinal information available on measures of health and health-related behavior, physical functioning (functional aging), personality, and cognitive abilities. These studies have been instrumental in demonstrating that genetic effects decrease in their importance as we age, at least for cognitive abilities. Furthermore, the importance of genetic effects depends on what measure we are studying.

Interest in normal aging has also lead us to study age related diseases such as Alzheimer's disease and other dementias, Parkinson's disease, and osteoporosis. In the dementia study known as Harmony, we have recently completed neuropsychological and diagnostic workups and risk factor assessments of over 1,500 twins with suspected cognitive impairment and their cotwins (over 2,000 subjects total).

A similar design is planned for the Parkinson's study, which included telephone interviews of occupational and leisure time activities followed by a neurological examination of approximately 400 suspected cases and their co-twins.

Psychiatric disorders

We also have a keen interest in psychiatric disorders such as depression, generalized anxiety disorder and substance use and abuse. Research questions include: Are there associations with candidate genes and depressed mood; what is the genetic epidemiology of late age of onset depression; To what extent do depression, dementia, and Parkinson's disease share common etiologies.

Current supervision of post docs

Current supervision of PhD students