Human Research Ethics Online Training

Case Study 1: The Vipeholm Caries Study

Probably the most ethically controversial dental research took place at the Vipeholm Hospital in Lund, Sweden between 1945 and 1954 [1].

The Vipeholm Hospital was described as an institute for the “mentally deficient” receiving patients from all parts of Sweden. The main psychiatric conditions described were “idiocy” and “imbecility”. Most patients spent their whole lives there.

The study was started before the introduction of the Nuremberg Code in 1947, but the study continued for 7 years after the Code’s introduction.
[1] The Vipeholm caries study. Gustafsson BE, Quensel C-E, Lanker LS, Lundqvist C, Grahnen H, Bonow BE, Krasse B. 1954 Acta Odontol Scand. Vol 11, Issue 3-4, 232-264

p25This image was taken in 1908. Photographer unknown.

The aim of the study was to determine the relationship between carbohydrate intake and dental caries (tooth decay) with the subjects in some groups fed caramels and toffees between meals, whilst other groups received extra carbohydrates at mealtimes. The study was performed under the direction of the Swedish Medical Board and was funded by the government, research funds and the chocolate and sweet manufacturers.

The results of the study were:

  • all groups showed a slow but definite increase in bodyweight
  • DMF (i.e. the number of decayed, missing and filled teeth) increased over the course of the study with the biggest increases in those groups consuming additional carbohydrates between meals.
  • these increases stopped when the diet reverted to the pre-study diet.

The study also reported that prior to 1950 the majority of patients received no dental care (only 5.6% of existing cavities had been filled, and some extractions performed).

By the end of the study, the number of unfilled cavities had increased from 11,238 to 13,363

The study was conducted entirely without the consent of patients or their carers/families. Ethical issues were not discussed at staff meetings or mentioned in the original study paper, with the dentists involved reported as not seeing any ethical problems with the study itself.

After an initial release of some study results in 1952, some study funds were withdrawn (sugar manufacturer). Continuation of the studies was now dependent on government funding. However, in 1954 a bill was introduced into the Swedish parliament suggesting that new grants for the project should be refused and this was followed by the government not allowing the patients at Vipeholm to be used as research subjects from July 1955 onwards.

One of the participating dentists (Bo Krasse) still argues that the study is ethically defendable [1]. Indeed, the study had some very positive outcomes, including:

  • a desirable objective
  • meticulous, credible results
  • providing information regarding caries risk and frequent ingestion of sugar allowing the introduction of public health messages.
  • stimulating research on sugar-substitutes.

[1] The Vipeholm dental caries study: Recollections and reflections 50 years later. Bo Krasse. J Dent Res 80(9): 1785-1788, 2001.


Which basic tenets of ethical research practice do you think have been violated in this study?

Answer: All of them.

  •  Beneficence: benefits to research participants should be optimal, whilst risks should be reduced to a minimum. Participants had an increased rate of tooth decay  and although it has been suggested that inmates received fillings, the study report does not indicate this.
  •  Justice: no one group should disproportionately bear the risks of research (e.g. mentally disabled).
  •  Respect: every participant has the right to informed consent.
  •  Vulnerable groups: as a vulnerable group, the mentally disabled residents at the Vipeholm Hospital were subordinate members of a hierarchical group.

Useful reading for those who want to know more about the events at Vipeholm:
Voices from Vipeholm, eds. Cecilia Nilsson and Carl-Ola Holmér, Foundation Medical history museums in Lund and Helsingborg. 1998