Northern Wisconsin




Sunweavers is a community-based research project focused on vitamin D and cardiac health in American Indian women. Vitamin D is important for bone and muscle health, it may also benefit the heart and blood vessels and might be involved in blood sugar control. We obtain vitamin D naturally from sun exposure to our skin, through a small number of foods or via supplements.

Many people do not get enough vitamin D. Importantly, people living in the northern parts of the world do not make vitamin D in the fall and winter due to low sunlight exposure.  Additionally, even in sunny climates, those who spend a lot of time inside or cover most of their skin with clothes or sunscreen when outdoors do not get enough sun exposure to have good vitamin D levels. Moreover, older people and those who have darker skin need more sun exposure to make enough vitamin D. As a result, vitamin D inadequacy is common worldwide.  As vitamin D is important for strong bones and muscles, people with low vitamin D are at increased risk for falls and fractures.  An accumulating body of evidence relates low vitamin D status to a multitude of other diseases, potentially including cardiovascular disease and diabetes mellitus.

The main purpose of the Sunweavers study is to see if American Indian women supplemented with a higher vitamin D dose than often used (2,500 IU daily) have improvements in blood vessel function. To evaluate this possibility, researchers measured blood pressure and used sound waves (ultrasound) to assess how efficiently blood vessels work, they also assessed blood tests related to diabetes to see if these levels were affected.  Additionally, as there is little information about vitamin D levels in American Indians, we are conducting a sub-study where we are measuring vitamin D and related blood tests.


The study participants consisted of postmenopausal American Indian women of the Stockbridge-Munsee and Menominee Tribes in northern Wisconsin.  The UW team is led by Drs. Neil Binkley, MD, and James Stein, MD with the UW SMPH Department of Medicine.  The research team works closely with collaborators at the Stockbridge Munsee health clinic and Tribal members of the Stockbridge Munsee Community and Menominee Nation.  The Ho-Chunk Nation in Baraboo and Black River Falls communities are participating the vitamin D level sub-study.  Other project partners are at the Essentia Institute of Rural Health in Duluth, MN.


99 Native women have enrolled in and completed the SUNWEAVERS study.  Results of data regarding the relationship between vitamin D and vascular function are currently being analyzed.  Evaluation of other parameters, such as a role of vitamin D in inflammation and blood tests related to diabetes will be reported later in 2015.

To date, there are 47 men and women that volunteered for the vitamin D sub-study.  Importantly, almost ½ of this group are male, to our knowledge, there is currently no available information about vitamin D levels in American Indian men.  Study recruitment was completed in January 2015, and final results are expected in fall 2015.

Ongoing communication with Tribal Health Board membership has ensured our partners are informed about study implementation experiences, as well as study results, as they are determined.  Together we are developing methods to effectively deliver study findings back to the broader community and perhaps lead to new study projects of interest to Tribes. The Sunweavers research team will meet with the Stockbridge-Munsee Health Board and Tribal Council in Fall 2016 and hopes for permission to publish and to hear recommendations on community dissemination.

For more information, please contact Diane Krueger,

Updated Fall 2016.