Who Gets Lupus & Why?

It is estimated that the prevalence of lupus in the general population is 0.1%, or approximately 300,000 North Americans. Lupus can occur in both men and women, and at almost any age, but the typical patient is:

  • Aged 15-45 years old
  • Female, outnumbering male sufferers 8:1; (or more); in childhood or post-menopausal cases, the ratio is closer to 2:1
  • African-American and Hispanic, outnumbering Caucasians by as much as 4:1

The increased frequency of lupus within families – especially between identical twins – suggests the source of the disease is genetic in nature, likely a class of genes that is also though to be responsible for other autoimmune disorders in humans. However, as is the case with many of these conditions, the reason (or reasons) why this gene ultimately triggers lupus in some people and not others is poorly understood. The only factor known with some confidence is the role played by sex hormones, which likely influence the overwhelming majority of women amongst lupus sufferers.

It is also thought that a series of environmental factors serve to trigger the problematic immune response which defines lupus, including:

  • Infection, which could be responsible for inducing autoimmunity via molecular “mimicry”
  • Stress, which can provoke changes to immune-cell health and functionality
  • Diet, which can affect the production of “mediators” of inflammatory responses
  • Drug toxicity, which can modify the immune response at the cellular level
  • Sunlight, which stimulates inflammation and tissue damage

While no one single factor has been identified as the critical trigger for lupus, the combination of one or more of these factors in a genetically or hormonally predisposed individual could ultimately be responsible for the many different manifestations of the disease and alternating periods of flare-ups and remission.