1. Epidemiology and Global Health
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Body height in young adult men and risk of dementia later in adult life

  1. Terese Sara Høj Jørgensen  Is a corresponding author
  2. Gunhild Tidemann Okholm
  3. Kaare Christensen
  4. Thorkild IA Sørensen
  5. Merere Osler
  1. Bispebjerg and Frederiksberg Hospital, Denmark
  2. University of Copenhagen, Denmark
  3. University of Southern Denmark, Denmark
Research Article
Cite this article as: eLife 2020;9:e51168 doi: 10.7554/eLife.51168
2 figures, 3 tables and 6 additional files

Figures

Figure 1 with 1 supplement
Selection of the study population.
Figure 1—figure supplement 1
Time line of data collection from each of the registers and the total follow-up time.

Foot note: *Anatomic Therapeutical Chemical (ATC) code for dementia (N06D) is also used for patients with Parkinson’s disease, but the treatment is only indicated if the patients have comorbid dementia. **Dementia was identified by international classification of disease (ICD) version 8 codes (290.00–290.99) until the end of 1994 and by ICD10 codes (F00.0-F03.9; G30.0-G30.9) from 1995 and thereafter.

Figure 2 with 1 supplement
Hazard Ratios (HRs) and corresponding 95% confidence intervals (95% CIs) for the association between z-score of body height at the entry to adulthood as a cubic spline with four knots and dementia.

A z-score of 0 is the reference value. Stratified by birth cohort and adjusted for conscript board district, educational level and intelligence test scores. Age included as underlying scale of the model. The analysis included the total population of men. Identify cohort-specific values of one z-score in Supplementary file 2.

Figure 2—figure supplement 1
Distribution of mean numeric difference in body height in cm between brothers (A) and twins (B).

Note: to hide micro data, the value 26 includes all values above for brother and the value 17 includes all values above for twins. In cases where there were more than two brothers with a shared mother, the difference in body height between all brothers were included. For example, for a groups of three brothers, the differences between brother one and two, brother one and three, and brother two and three, respectively, were included.

Tables

Table 1
Hazard ratios (HRs) and corresponding 95% confidence intervals (95% CIs) of the association between taller body height at entry to adulthood and dementia diagnoses among the total population of men.
Descriptive statisticsHR (95% CI) for onset of dementia per one z-score* higher
Mean height (Standard diviation)Dementia cases
Number (%)
Model 1Model 2aModel 2b§Model 3
176.8
(6.6)
10,599
(1.6)
0.86
(0.85;0.87)
0.88
(0.87;0.89)
0.90
(0.89;0.90)
0.90
(0.89;0.90)
  1. *Identify cohort-specific values of one z-score in Supplementary file 2.

    Model 1: Stratified by birthcohort and conscript board district. Age included as underlying scale of the model.

  2. Model 2a: Model 1 + adjusted for educational level.

    §Model 2b: Model 1 + adjusted for intelligence test scores.

  3. Model 3: Model 1 + adjusted for educational level and intelligence test scores.

Table 2
Fully adjusted* hazard ratios (HRs) and corresponding 95% confidence intervals (95% CIs) of the association between taller body height at entry to adulthood and dementia diagnosis among all men.
Dementia cases
Number (%)
HR (95% CI) for onset of dementia per one z-score* higher
<60 years
4191 (0.6)0.87 (0.84;0.90)
≥60 years
6408 (1.3)0.91 (0.90;0.92)
  1. *Identify cohort-specific values of one z-score in Supplementary file 2.

    Model 3: stratified by birth cohort and adjusted for conscript board district, educational level and intelligence test scores. Age included as underlying scale of the model.

Table 3
Fully adjusted* hazard ratios (HRs) and corresponding 95% confidence intervals (95% CIs) of the association between taller body height at entry to adulthood and dementia diagnosis among brothers and twins
Descriptive statisticsHR (95% CI) for onset of dementia per one z-score* higher
Mean height
(standard deviation)
Dementia cases
Number (%)
Cohort analysesWithin-brother/twin analyses
Brothers
177.8 (6.6)597 (0.8)0.90 (0.82;0.98)0.78 (0.64;0.96)
Twins
175.8 (6.7)107 (1.4)0.91 (0.73;1.16)0.86 (0.44;1.68)
  1. *Identify cohort-specific values of one z-score in Supplementary file 2.

    Model 3: Stratified by birth cohort and adjusted for conscript board district, educational level and intelligence test scores. Age included as underlying scale of the model.

Data availability

We have uploaded a file with the code used to program the statistical analyses performed in Stata. To access the anonymised dataset used in this study, researchers need to apply the Danish Conscript board steering committee and Statistics Denmark. Only aggregated data, where no identification of persons is possible i.e. minimum five observations in each cell, can be removed from the server containing the data accessed through Statistics Denmark. Thus, we cannot provide an anonymised copy of the dataset as individuals may be identified based on the information in the data e.g. birthday, height, dementia status etc. Access to the data through Statistics Denmark is only granted for authorised research and analysis environments of a more permanent nature with a chief researcher and several researchers/analysts. Foreign researchers affiliated to a Danish authorised environment can also get access. Authorisation is granted by the Director General. Please find more information in the document 'Access to micro data at Statistics Denmark_2014' on https://www.dst.dk/en/TilSalg/Forskningsservice.

Additional files

Source code 1

Stata code used for the analyses.

https://cdn.elifesciences.org/articles/51168/elife-51168-code1-v1.do
Supplementary file 1

Distribution of covariates for body height and dementia diagnoses among the total population of men.

https://cdn.elifesciences.org/articles/51168/elife-51168-supp1-v1.docx
Supplementary file 2

Mean body height (z-scores) in cm for each of the birth cohorts in the full study population, brothers and twins.

https://cdn.elifesciences.org/articles/51168/elife-51168-supp2-v1.docx
Supplementary file 3

Fully adjusted* hazard ratios (HRs) of the association between taller body height at entry to adulthood and dementia diagnosis among all men before 1995 and from 1995 and onwards.

https://cdn.elifesciences.org/articles/51168/elife-51168-supp3-v1.docx
Supplementary file 4

Frequency (%) of individuals included from each birth cohort in the brother analyses.

https://cdn.elifesciences.org/articles/51168/elife-51168-supp4-v1.docx
Transparent reporting form
https://cdn.elifesciences.org/articles/51168/elife-51168-transrepform-v1.docx

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