Calcium-Rich Food Versus Calcium Carbonate for Bone Health

Calcium intake is an important component of bone health and osteoporosis prevention. Despite widespread recommendations for calcium supplementation, long-term adherence to traditional calcium supplements is often poor because of gastrointestinal side effects, difficulty swallowing tablets, and dissatisfaction with conventional formulations. This study is designed to compare adherence, tolerability, safety, and treatment satisfaction between a calcium-rich food and a traditional calcium carbonate supplement in women at increased risk for osteoporosis.

Participants will be randomized in a 1:1 ratio to receive either a calcium-rich food providing 500 mg of calcium from milk-derived minerals or a 500 mg calcium carbonate supplement once daily for four weeks. Randomization will be administered using REDCap with blocked randomization (block size of four) and age stratification to ensure balanced allocation across age groups. A seven-day washout period without calcium supplements will precede study initiation. Participants will complete a baseline questionnaire followed by weekly questionnaires throughout the four-week intervention period.

The primary objective is to compare continuous adherence between study groups over the four-week intervention. Adherence will be calculated using measures of compliance and persistence derived from participants' weekly self-reported missed doses. The Morisky Medication Adherence Scale will also be collected as a secondary measure to support construct validity and comparison with prior osteoporosis research.

Secondary outcomes include gastrointestinal tolerability, treatment satisfaction, and safety. Gastrointestinal symptoms will be assessed using the Gastrointestinal Symptom Rating Scale, treatment satisfaction will be assessed using selected domains of the Treatment Satisfaction Questionnaire for Medication, and the frequency of gastrointestinal symptoms, including bloating and constipation, will be compared between study groups.

Eligible participants are women aged 40 to 90 years with either a family history of osteoporosis or a history of fracture who are willing to comply with study procedures and provide written informed consent. Individuals with medical conditions that would interfere with study participation, severe allergies to study ingredients, pregnancy, breastfeeding, dysphagia, or participation in another research study will be excluded.

The primary analysis will compare continuous adherence between groups using an independent two-sample t-test with a pre-specified Mann-Whitney U sensitivity analysis. Secondary outcomes will be analyzed using appropriate parametric or nonparametric statistical methods, with statistical significance defined as a two-sided p-value of less than 0.05

Inclusion criteria

Female at birth, 40 to 90 years of age Family history of osteoporosis or history of fracture Willing and able to provide written informed consent Willing to comply with all study procedures Willing to refrain from making major dietary changes during the 4-week study No known allergy or intolerance to any study product ingredients Exclusion Criteria Medical condition that would interfere with study participation or adherence (including selected oncologic or psychiatric disorders) Known severe allergic reaction requiring an epinephrine auto-injector Pregnant, breastfeeding, or planning to become pregnant during the study Invasive medical procedure within the previous 3 months or planned during the study period Current participation in another research study or planning to participate during the study period Difficulty swallowing (dysphagia)

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