Vitamin D's Effect on Physical Performance in the Elderly

Systolic blood pressure, diastolic blood pressure, and pulse will be measured to the nearest even digit by use of a random-zero sphygmomanometer (Mabis, IL, USA). Three readings will be made with the subjects seated after they have rested for five minutes. The average of the second and third readings will be used in the analysis.

Systolic blood pressure, diastolic blood pressure, and pulse will be measured to the nearest even digit by use of a random-zero sphygmomanometer (Mabis, IL, USA). Three readings will be made with the subjects seated after they have rested for five minutes. The average of the second and third readings will be used in the analysis.

Systolic blood pressure, diastolic blood pressure, and pulse will be measured to the nearest even digit by use of a random-zero sphygmomanometer (Mabis, IL, USA). Three readings will be made with the subjects seated after they have rested for five minutes. The average of the second and third readings will be used in the analysis.

Dual task - Participants will be asked to perform the following tasks in a random order: usual walking (single task 1), counting backwards by 1 from 50 while standing (single task 2), and counting backwards by 1 from 50 while walking (dual task). Each participant's performance while walking during single and dual task test (without prioritizing either task) will be assessed by using the GAITRite portable electronic walkway system. The GAITRite system includes a 600 cm long and 64 cm wide walkway mat that is used to measure spatiotemporal gait parameters. The mat has imbedded sensors that are activated and deactivated according to foot pressure and is capable of measuring milliseconds and millimeters for time and length parameters, respectively. Before each trial participants will be given standardized instruction and a visual demonstration. The participants will be wearing comfortable, low-heeled shoes and will walk the length of the mat at the pace they select.

Dual task - Participants will be asked to perform the following tasks in a random order: usual walking (single task 1), counting backwards by 1 from 50 while standing (single task 2), and counting backwards by 1 from 50 while walking (dual task). Each participant's performance while walking during single and dual task test (without prioritizing either task) will be assessed by using the GAITRite portable electronic walkway system. The GAITRite system includes a 600 cm long and 64 cm wide walkway mat that is used to measure spatiotemporal gait parameters. The mat has imbedded sensors that are activated and deactivated according to foot pressure and is capable of measuring milliseconds and millimeters for time and length parameters, respectively. Before each trial participants will be given standardized instruction and a visual demonstration. The participants will be wearing comfortable, low-heeled shoes and will walk the length of the mat at the pace they select.

Dual task - Participants will be asked to perform the following tasks in a random order: usual walking (single task 1), counting backwards by 1 from 50 while standing (single task 2), and counting backwards by 1 from 50 while walking (dual task). Each participant's performance while walking during single and dual task test (without prioritizing either task) will be assessed by using the GAITRite portable electronic walkway system. The GAITRite system includes a 600 cm long and 64 cm wide walkway mat that is used to measure spatiotemporal gait parameters. The mat has imbedded sensors that are activated and deactivated according to foot pressure and is capable of measuring milliseconds and millimeters for time and length parameters, respectively. Before each trial participants will be given standardized instruction and a visual demonstration. The participants will be wearing comfortable, low-heeled shoes and will walk the length of the mat at the pace they select.

Dual task - Participants will be asked to perform the following tasks in a random order: usual walking (single task 1), counting backwards by 1 from 50 while standing (single task 2), and counting backwards by 1 from 50 while walking (dual task). Each participant's performance while walking during single and dual task test (without prioritizing either task) will be assessed by using the GAITRite portable electronic walkway system. The GAITRite system includes a 600 cm long and 64 cm wide walkway mat that is used to measure spatiotemporal gait parameters. The mat has imbedded sensors that are activated and deactivated according to foot pressure and is capable of measuring milliseconds and millimeters for time and length parameters, respectively. Before each trial participants will be given standardized instruction and a visual demonstration. The participants will be wearing comfortable, low-heeled shoes and will walk the length of the mat at the pace they select.

Dual task - Participants will be asked to perform the following tasks in a random order: usual walking (single task 1), counting backwards by 1 from 50 while standing (single task 2), and counting backwards by 1 from 50 while walking (dual task). Each participant's performance while walking during single and dual task test (without prioritizing either task) will be assessed by using the GAITRite portable electronic walkway system. The GAITRite system includes a 600 cm long and 64 cm wide walkway mat that is used to measure spatiotemporal gait parameters. The mat has imbedded sensors that are activated and deactivated according to foot pressure and is capable of measuring milliseconds and millimeters for time and length parameters, respectively. Before each trial participants will be given standardized instruction and a visual demonstration. The participants will be wearing comfortable, low-heeled shoes and will walk the length of the mat at the pace they select.

Balance and physical performance as measured with the Established Population for Epidemiologic Studies of the Elderly physical performance battery (EPESE), which includes: (a) side by side stands, (b) semi-tandem stand, (c) tandem stand, (d) measured walk, (e) repeated chair stands, and (f) timed chair stands.

Flexibility with the Sit and Reach Test will be assessed with the most common flexibility test by measuring the flexibility of the lower back and hamstrings. A box about 30 cm high and a meter rule is used to have the subject sit on the floor with his/her back straight. Legs are held straight ahead and knees flat against the floor. The box is placed flat against the feet (no shoes), and the arms are stretched out toward the box. The slide ruler on top of the box is positioned at the zero point. The subject leans forward slowly (without jerking or bouncing) as far as possible keeping the fingertips level with each other and the legs flat. The subject reaches slowly along the length of the ruler 3 times. On the third attempt, the subject reaches as far as possible and holds for 2 seconds and the score is recorded.

Physical activity will be assessed with International Physical Activity Questionnaire (IPAQ). The IPAQ items are structured to provide individual domain specific scores for walking, moderate-intensity, and vigorous activity within the domains of work, transportation, domestic chores and gardening, and leisure-time. The tool asks about the time spent doing a specific physical activity in the last 7 days. For total scores, the duration (in minutes) and frequency for all types of activities in all domains are summed, while specific domain scores are calculated by the summation of the walking, moderate-intensity and vigorous-intensity activities within the specific domain. For activity-specific scores, the scores for the specific type of activity across domains are added. To measure the volume of activity, each type of activity is weighted by its energy requirement defined as the MET-min.

Vitamin D and Calcium intake will be assessed using a Vitamin D and Calcium Food Frequency Questionnaire. This tool allows estimation of the relative nutrient intakes based on foods eaten, frequency, and size. This short FFQ contains only 24 foods and beverages, and it is designed to assess vitamin D and calcium intake. The FFQ asks how frequently (never or less than once per month; 1/ month; 2-3/month; 1/week; 2/weeks; 3-4/week; 5-6/week; 1/day; 2-3/day) and how much of each of these foods is consumed based on medium serving size (small, medium, large). The short FFQ is associated with a database; therefore allowing the estimation of nutrient intakes for the reported portion size. Vitamin D and calcium values for the 24 foods will be recorded from the Diet History Questionnaire database developed by the National Cancer Institute, according to serving size.

The 6-item U.S. Household Food Security Survey Module will be used to assess food security. The 6-item scale was developed by the National Center for Health Statistics. It asks the participant questions on foods eaten in the household in the last 12 months and whether they were able to afford the foods needed. Scores are coded as affirmative responses that are summed up to get a score. A score of 0-1 means high or marginal food security, 2-4 means low food security, and 5-6 means very low food security.

Sun Exposure Recall Questionnaire - Subjects' recollection of usual sun exposure over the previous year will be assessed via a questionnaire. This instrument measures the amount of time spent outdoors from 9 AM - 5 PM and amount of skin exposed for everyday of the week during summer and fall (June - December) and winter and spring (January - May), independently. This instrument also includes questions about sun protective behaviors including sunscreen and umbrella use. A scoring system is used to quantify time outdoors (<5 minutes; 5-30 minutes; and >30 min), sunscreen use, umbrella use, and amount of skin exposed (hands, face, arms, legs, bathing suit).

The SF-36v2TM Health Survey provides psychometrically-based physical and mental health summary measures and a preference-based health utility index. It is a generic measure that does not target a specific age, disease, or treatment group.

Depression will be assessed using the Beck's depression questionnaire (BDI-II). It is a self-report 21 item instrument to assess the existence and severity of depressive symptoms. Each item corresponds to a symptom of depression and has a four-point scale ranging from 0 to 3, except for 2 items that have seven options to indicate decrease or increase in appetite and sleep. The score of all items are summed to give a single score. A total score of 0-13 is considered minimal, 14-19 mild, 20-28 moderate, and 29-63 severe.

Fall Efficacy Scale International (FES-I) is a 16-question assessment tool used to evaluate the fear of falling while performing activities like cleaning the house, getting dressed/undressed, preparing simple meals, taking a bath/shower, going to shop, getting in/out of the chair, going up/down stairs, walking around the neighborhood, reaching something above head/on ground, going to answer the phone before it stops ringing, walking on slippery surface, visiting friend/relative, walking in crowds, walking on uneven surfaces, walking up/down slope, and going out to a social event. The participants will be asked to rate on a scale of 1 to 4 how concerned they are about the possibility of falling while performing these activities with 1 meaning "not at all concerned," 2 being "somewhat concerned," 3 being "fairly concerned," and 4 being "very concerned."

History of falls will be assessed by asking the participant if they recall experiencing one or more falls in the last 6 months. A fall will be defined as an event that results in the person unintentionally coming to rest on the ground or other lower level with or without injury that is not due to a major intrinsic event, like seizure, stroke, loss of consciousness, epilepsy, excess alcohol, or an environmental hazard like sustaining a blow.

Compliance will be measured using a modified version of the 8 item Morisky Medication Adherence Scale (MMAS-8). MMAS-8 is a generic self-report measure of medication taking behavior that does not target a specific age, disease, or treatment group.

Reflectance colorimetry - Reflectance colorimetry using the IMS SmartProbe 400 will be used objectively measure sun exposure and skin color. This instrument measures the skin's reflectance of white light over a spectrum of wavelengths. The light is shined on the chosen area and the intensity of light reflected is measured by the probe. Melanin absorbs UV light; therefore, the more melanin present, and hence, the darker the skin, the less light is reflected back to the probe. The results are based on the Commission Internationale de l'Eclairage L scale endorsed by the International Commission on Illumination system as a way to represent accurately human color perception.