Repeatability of a short food frequency questionnaire to assess calcium intake in older australians.

Objective. To assess the repeatability of the validated Flinders Calcium Food Frequency Questionnaire (FFQ(CA)) for estimating dietary calcium intake in a sample of community dwelling older Australians. Methods. A test-retest repeatability study involving 100 subjects (≥65 years) living independently in metropolitan Adelaide, Australia. Estimates of daily calcium intake from the first (FFQ(CA1)) and repeated administration (FFQ(CA2)) were calculated from two versions (35-item and 15-item) of the FFQ(CA). The intraclass correlation coefficient (ICC) was used to assess the repeatability. Results. Moderate and comparable ICC values (r = 0.5, r = 0.6) were found across the two versions of the FFQ(CA). Conclusion. Both FFQ(CA) versions demonstrated moderate repeatability, supporting the results of previous studies.

Relative validation of a short food frequency questionnaire to assess calcium intake in older adults.

OBJECTIVE: To develop and validate a food frequency questionnaire (FFQ) for estimating calcium intake in community-dwelling older adults using a food record as the reference method. METHOD: A validation study involving 102 subjects (67 females) aged > or =65 years and residing independently in Adelaide, Australia, between 2002-06 was performed. Estimates of calcium intake over the last year were calculated from two versions (35 and 15 items) of the FFQ and compared with average intake from four days of non-consecutive food records (4DFR). RESULTS: Mean calcium intake from the 4DFR was 987 mg/day (95% CI 922-1051). The 35 and 15-item questionnaires gave mean intakes of 992 mg/day (95% CI 913-1,071) and 1017 mg/day (95% CI 927-1,106) respectively. Mean difference (95% limits of agreement) between the food record and the 35 and 15-item questionnaires was 5 mg (-739-729) and 28 mg (-936-879) respectively. The 15-item questionnaire demonstrated 82% sensitivity for classifying subjects with calcium intake below the estimated average requirement (EAR, 840 mg for males 51-70 years; 1,100 mg for females >51 years and males >70 years of age) and 46% specificity for classifying subjects with intake above the EAR. CONCLUSION: The FFQ evaluated as part of this study is one of very few that has been tested across both genders and in older adults specifically. The 15-item version has demonstrated a level of sensitivity and specificity comparable with other FFQs for evaluating calcium intake. IMPLICATIONS: The 15-item FFQ can be confidently used for measuring group mean calcium intake in older Australians or as a screening tool to allow health professionals to identify those who are most at risk of inadequate dietary calcium intake.

Facilitation of cortically evoked potentials with motor imagery during post-exercise depression of corticospinal excitability.

This study examined whether muscle fatigue alters the facilitatory effect of motor imagery on corticospinal excitability. We aimed to determine if post-exercise depression of potentials evoked magnetically from the motor cortex is associated with alterations in internally generated movement plans. In experiment 1, motor-evoked potentials (MEPs) were recorded from two right hand and two right forearm muscles, at rest and during motor imagery of a maximal handgrip contraction, in eight neurologically normal subjects, before and after a 2-min maximal voluntary handgrip contraction. Resting MEP amplitude was facilitated by motor imagery in three of the four muscles, but consistently only in two. Motor imagery also reduced the trial-to-trial variability of resting MEPs. Following the exercise, resting MEP amplitude was depressed reliably in only one muscle engaged in the task, although two other muscles exhibited some depression. Motor imagery MEPs were smaller after exercise, but the degree of facilitation compared to the rest MEP was unchanged. In experiment 2, TMS intensity was increased after exercise-induced MEP depression so that the MEP amplitude matched the pre-exercise baseline. The amplitude of the MEP facilitated with motor imagery was not altered by MEP depression, nor was it increased when the TMS intensity was increased. These results suggest, at least with a simple motor task, that while post-exercise depression reduces corticospinal excitability, it does not appear to significantly affect the strength of the input to the motor cortex from those areas of the brain responsible for the storage and generation of internal representations of movement.