Table 1 Aggregated list of potential patient identifiers in datasets

Direct

Name [9–16]

Initials [14]

Address, including full or partial postal code [9–16]

Telephone or fax numbers or contact information [9, 11, 13, 16]

Electronic mail addresses [9]

Unique identifying numbers [9–16]

Generalised HIPPA item 7-10, 18

Vehicle identifiers [9]

Medical device identifiers [9]

Web or internet protocol addresses [9]

Biometric data [9]

Facial photograph or comparable image [9, 11, 12, 14]

Audiotapes [12]

Names of relatives [11]

Dates related to an individual (including date of birth) [9, 10, 12, 16]

Indirect--may present a risk if present in combination with others in the list

Place of treatment or health professional responsible for care [11, 16]

Could be inferred from investigator affiliations

Sex [10]

Rare disease or treatment [11]

Sensitive data, such as illicit drug use or "risky behaviour" [16]

Place of birth [11, 16]

Socioeconomic data, such as occupation or place of work, income, or education [10, 11, 13, 16]

MRC requirement is for "rare" occupations only

Household and family composition [16]

Anthropometry measures [16]

Multiple pregnancies [16]

Ethnicity [10]

Small denominators--population size of <100 [15]

Very small numerators--event counts of <3 [15]

Year of birth or age (this article)

Age is potentially identifying if the recruitment period is short and is fully described

Verbatim responses or transcripts [16]