Participants in the Longitudinal Follow-ups of the Intensive Protocol of the Berlin Aging Study: Sample Description

Survivors of the initial N = 516 sample were recontacted and asked to participate in a follow-up of the multidisciplinary Intensive Protocol at four occasions, 1995-1996 (reduced to 6 sessions), 1997-1998 (6 sessions), 2000 (3 sessions), and 2004-2005 (3 sessions) (see Table 2). Table 4 summarizes the frequency distribution of participants tested at these four occasions in terms of the six age/cohort groups of the original BASE design (Time 1).

The distribution of participants' actual ages is given in Table 5. As can be seen in Table 5, the stratified (balanced) age distribution of the 516 participants at the first measurement occasion was not maintained in the longitudinal follow-ups.

In the first follow-up of the Intensive Protocol in 1995-1996, N = 313 (60.7%) of the baseline sample were still alive. Of these, N = 206 (65,8%) participated in all six sessions of multidisciplinary assessment. This follow-up sample consisted of 101 men and 105 women. The frequency distribution of this longitudinal sample in terms of the original BASE age/cohort design is given in column 2 of Table 4. Column 2 of Table 5 shows the actual age distribution at the 1995-1996 assessment. The average time interval between baseline assessment and the first Intensive Protocol follow-up was 3.8 years (range 2.4-5.2 years). For most participants, the Intensive Protocol follow-up data collection was spread over 3 - 4 months (mean: 3.7 months; range: 1.2-14.6 months). Incomplete data was obtained from an additional N = 50 (16.0% of survivors): 38 individuals participated only in one multidisciplinary session (a follow-up of the multidisciplinary Intake Assessment). 18.2% of the survivors did not participate in any level of the follow-up. Table 6 provides demographic information for participants in the N = 206 longitudinal sample who completed the first follow-up of the Intensive Protocol (1995-1996). Differences due to attrition between this longitudinal sample and the BASE N = 516 sample can be determined by comparing information in column 1 in Table 6 with Table 1.

The second follow-up of the Intensive Protocol was conducted in 1997-1998 (see Table 2). At this measurement occasion, N = 239 (46.3%) of the baseline sample had survived. Of these, N = 132 (55.2%) were participating in the six sessions of multidisciplinary assessment. This follow-up sample consisted of 60 men and 72 women. The frequency distribution of this longitudinal sample in terms of the original BASE age/cohort design is given in column 3 of Table 4. Column 3 of Table 5 shows the actual age distribution at the 1997-1998 measurement. The average time interval between baseline assessment and the second Intensive Protocol follow-up was 5.5 years (range 4.2-7.0 years). The average time interval between the first and the second Intensive follow-up was 1.8 years (range 1.0-2.6 years). Incomplete data was obtained from an additional N = 38 (15.9% of survivors): 32 individuals participated only in one multidisciplinary session (a follow-up of the multidisciplinary Intake Assessment). 28.9% of the survivors did not participate in any level of the follow-up. Table 7 provides demographic information for participants in the N = 132 longitudinal sample who completed the second follow-up of the Intensive Protocol (1997-1998). Differences due to attrition between this longitudinal sample and the BASE N = 516 sample can be determined by comparing information in column 1 in Table 7 with Table 1.

The third follow-up of the Intensive Protocol was conducted in 2000 (see Table 2). At this measurement occasion, N = 164 (31.8%) of the baseline sample had survived. Of these, N = 82 (50.0%) were participating in the three sessions of multidisciplinary assessment. This follow-up sample consisted of 32 men and 50 women. The frequency distribution of this longitudinal sample in terms of the original BASE age/cohort design is given in column 4 of Table 4. Column 4 of Table 5 shows the actual age distribution at the 2000 measurement. The average time interval between baseline assessment and the third Intensive Protocol follow-up was 8.9 years (range 7.2-10.5 years). The average time interval between the second and the third Intensive follow-up was 3.4 years (range 2.8-3.7 years). Incomplete data was obtained from an additional N = XX (XX% of survivors): XX individuals participated only in one multidisciplinary session (a follow-up of the multidisciplinary Intake Assessment). XX% of the survivors did not participate in any level of the follow-up. Table 13 provides demographic information for participants in the N = 82 longitudinal sample who completed the third follow-up of the Intensive Protocol (2000). Differences due to attrition between this longitudinal sample and the BASE N = 516 sample can be determined by comparing information in column 1 in Table 13 with Table 1.

The fourth follow-up of the Intensive Protocol was conducted in 2004-2005 (see Table 2). At this measurement occasion, N = XX (XX%) of the baseline sample had survived. Of these, N = 46 (XX%) were participating in the three sessions of multidisciplinary assessment. This follow-up sample consisted of 16 men and 30 women. The frequency distribution of this longitudinal sample in terms of the original BASE age/cohort design is given in column 5 of Table 4. Column 5 of Table 5 shows the actual age distribution at the 2004-2005 measurement. The average time interval between baseline assessment and the fourth Intensive Protocol follow-up was 13.0 years (range 11.3-14.5 years). The average time interval between the third and the fourth Intensive follow-up was 4.1 years (range3.6-4.5 years). Incomplete data was obtained from an additional N = XX (1XX% of survivors): XX individuals participated only in one multidisciplinary session (a follow-up of the multidisciplinary Intake Assessment). XX% of the survivors did not participate in any level of the follow-up. Table 14 provides demographic information for participants in the N = 46 longitudinal sample who completed the fourth follow-up of the Intensive Protocol (2004-2005). Differences due to attrition between this longitudinal sample and the BASE N = 516 sample can be determined by comparing information in column 1 in Table 14 with Table 1.

Besides these regular contacts two additional assessments were carried out:

First, following the first follow-up of the Intensive Protocol (1995-1996), a subgroup of the BASE longitudinal participants (n = 109, 52.9%) also agreed to take part in a one-year multiple-session assessment of everyday activities. Out of these n = 84 completed this study of everyday activities.

Second, there was a microlongitudinal assessment following the multidisciplinary Intake assessment 2005. n =37 individuals completed 6 to 8 sessions within a period of three weeks.

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