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--- family_relations [2023/07/11 09:40] – simone
+++ family_relations [2026/10/05 12:21] (current) – jasper
@@ Line 5: / Line 5: @@
 The basis of the family relations data within Lifelines consists of information from the municipal registries (Basisregistratie Personen (BRP)). Based on this information, researchers from the [[ugli|UGLI-consortium]] have optimized the family relations using recoded surname data (for privacy purposes) and data from questionnaires ([[family_composition|Family composition]]). The process of this optimization has been documented and can be found here: {{ :lifelines_familyreconstruction.pdf | Family relations reconstruction}}.
-These optimized family relations were then verified by the UGLI-consortium using available genetic data. The most recent version of the family relations data (sec_family_relations_v3.1) has been verified by using genetic data from [[gwas|GWAS (CytoSNP)]], [[ugli|UGLI 1 (GSA), and UGLI 2 (Affymetrix)]]. More detailed information on this process can be found in the quality control document of UGLI2-Affymetrix: {{ :QC_report_UGLI2_(release_1)-v1.pdf |QC_report_UGLI2_(release_1)-v1.pdf}}, page 6 - 9, section 6b and in the {{ :readme_family_relations_v3.1.pdf |readme of the familyrelations}}.
+These optimized family relations were then verified by the UGLI-consortium using available genetic data. The most recent version of the family relations data (sec_family_relations_v3.1; July 2023) has been verified by using genetic data from [[gwas|GWAS (CytoSNP)]], [[ugli|UGLI 1 (GSA), and UGLI 2 (Affymetrix)]]. More detailed information on this process can be found in the quality control document of UGLI2-Affymetrix: {{ :QC_report_UGLI2_(release_1)-v1.pdf |QC_report_UGLI2_(release_1)-v1.pdf}}, page 6 - 9, section 6b and in the {{ :readme_family_relations_v3.1.pdf |readme of the familyrelations}}.
-Note that the family relations file does not provide information on whether a family member lives in the same house. Information on [[default_variables|postal code 4]] is available in your data by default and data on [[household_composition|household composition]] can be requested in our [[https://data-catalogue.lifelines.nl/|catalogue]].
+Note that the family relations file does not provide information on whether a family member lives in the same house. Information on [[default_variables|postal code 4]] is available in your data by default and data on [[household_composition|household composition]] can be requested through our [[https://data-catalogue.lifelines.nl/|catalogue]].
-===== Data and structure =====
+The family relations file is not available through our catalogue, but can be requested by sending an e-mail to data@lifelines.nl (this does not apply to UGLI consortium cluster users, who can already find the file in pheno_lifelines). If you do not already have access to the family relation file, please also complete our [[https://www.lifelines.nl/researcher/how-to-apply|amendment form]].
+===== Data and Structure =====
 The data in sec_family_relations_v3.1 consists of 5 columns:
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 The identifiers can be used to pair the family data to other phenotypic and genotypic data. The same participant identifier can also be found in the column for father or mother and partner. In which column the identifier can be found, depends on the participant's family size and if they are, for example, both a child and a parent. With the use of self reported data on family members like birthdays of parents and siblings, family members shared between siblings could be derived. These are family members that do not participate in Lifelines. Other than the family member connection, we do not have any other information on these persons. These derived family members have received a unique identifier (an S-number, i.e. S1031206). This identifier cannot be used to pair the data to other Lifelines data. An example is when two siblings have indicated to have the same parent; the (non-participating) parent has then received an S-number.
 The family id is used to identify participants that are part of the same family. Couples who share a household, but don't have children, also receive a family id. This provides the opportunity to work on research involving environmental factors. Note that partner information is based on [[1A|baseline data]].
+===== Interpretation of FAM_ID (Family id) =====
+In the family relations file, FAM_ID was updated following quality control of the genetic data. If first-degree relatives were identified who linked two or more previously separate families, these families were merged under a single FAM_ID. In such cases, one of the existing FAM_IDs was retained and the others were removed.
+Importantly, participants sharing the same FAM_ID are not necessarily all genetically related to one another. A family group may include multiple participants who are connected through both genetic and non-genetic relationships. For example, siblings and their respective partners may all share the same FAM_ID, even though the partners are not genetically related to each other or to their partner’s sibling.
+It is also possible for a participant who is not genetically related to the other members of their original family group, such as a partner, to be identified through the genetic data as a first-degree relative of someone in another family. In that case, the two family groups were also merged, and all participants in both groups were assigned the same FAM_ID.
+Therefore, FAM_ID should be interpreted as identifying a connected family group rather than a group in which every participant is genetically related to every other participant.
+===== Family Duos and Trios =====
+From the family relations file the following numbers have been extracted:
+{{:family_relations.png?600|}}
+Based on BRP and self-report, the following Lifelines [[https://en.wikipedia.org/wiki/Nuclear_family|nuclear families]] can be identified:
+| Number of families       |        ^ Child(ren) = LL Participant(s)                             |||||
+^ Parent = LL participant  | Total  | 1                               | 2      | 3     | 4    | 5    |
+| Only the mother          | ~2200  | ~1500                           | ~600   | ~80   | <10  | <10  |
+| Only the father          | ~350   | ~250                            | ~80    | ~10   | <10  | <10  |
+| Mother and father        | ~5000  | ~2600                           | ~2000  | ~350  | ~40  | <10  |
+Other family connections (e.g. grandparent-grandchild, siblings) are present in the cohort as well.
+===== Twins and Triplets =====
+Participants [[multiple_births|self-reported]] on being part of a twin or triplet, or [[pregnancy_outcomes|giving birth]] to a twin or triplet.
+Based on birth and family records, the following numbers were identified within Lifelines:
+  * Twins: 632 pairs (1,264 unique individuals)
+      * Monozygotic (MZ): 152 pairs
+      * Dizygotic (DZ): 350 pairs
+      * Zygosity undetermined: 130 pairs
+  * Triplets: 6 sets (18 unique individuals). As far as could be ascertained, none of these sets included  monozygotic pairs or trios.
+The classification of twin zygosity was determined using a combination of DNA data, sex, and questionnaire responses (see Table 1).
+^ Method                                 ^ DZ   ^ MZ   ^
+| DNA                                    | 134  | 124  |
+| Mixed gender                           | 187  | –    |
+| Questionnaire completed by both twins  | 10   | 15   |
+| Questionnaire completed by one twin    | 19   | 13   |
+| Total                                  | 350  | 152  |