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South Dakota Rural Bone Health Study

The aim of this study was to determine whether a rural lifestyle leads to high bone density in young adulthood and lowers the rate of bone loss later in life. Over 1,500 men and women aged 20 to 65 years with equal numbers of Hutterites, rural non-Hutterites and non-rural non-Hutterites were followed longitudinally. Yearly blood samples, bone measurements and regular assessments of activity levels and dietary intake were obtained. The project will determine whether bone density during young adulthood and the rate of later bone loss among the Hutterite population is similar to other populations, and whether greater activity levels and calcium intake can account for the high bone density observed among the Hutterites. We also investigated genetic factors affecting bone strength. Further understanding of the role of genetics and lifestyle factors as determinants of bone density among Hutterites is necessary because they appear to be less likely to develop osteoporosis than the normal U.S. population.

Past newsletters for the SDRBH 

Some results from the SDRBH Study

When we analyze data collected from the study, we answer specific questions to learn something new about health or disease. We write up the results for publication in medical journals. These publications help generate public health policy and are important for understanding how to prevent diseases.

What we have found so far:

  • Rural men and women have greater bone mass and size than non-rural men and women. Individuals with greater activity levels and greater grip strength have better bones. Population differences in bone could not be explained by current activity levels or calcium intake.
    • These findings were based on the first visit only and were published in the international medical journal Bone in 2004. The populations included rural (both Hutterite and non-Hutterite) an non-rural groups.
  • Leptin is a hormone that is thought to be related to bone density. We found higher levels of leptin among Hutterites compared to non-Hutterites, but this did not explain why Hutterites have high bone density.
    • These findings were published in the international medical journal Bone in 2004.
  • It is known that bone density decreases during breast-feeding and is regained during weaning. Other scientists report a protective effect of breast-feeding on later risk of hip fracture, but no difference in bone density is found between women who breast-fed and those who did not. We found that the more children a woman breast-feeds, the stronger her bones. The increase in bone strength is due to an increase in bone size, not bone density.
    • We speculate that the increase in bone size is from the added weight and stress placed on bones during pregnancy- a type of "exercise" for the bones. These findings were published in the medical journal Osteoporosis International in 2005.
  • Men with the lowest percent fat in their trunk area (abdomen) had higher levels of "good" cholesterol and the lowest total cholesterol/HDL ratio - low ratios are beneficial. In both men and women, cholesterol and triglyceride concentrations were more related to fat in the trunk area than to the total body percent fat.
    • These findings were published in the Journal of Nutrition, Health and Again in 2006. These findings confirm reports that show increased heart disease risk in individuals with high amounts of fat in their trunk region, or abdomen.
  • Men who are sleep deprived (<6.5 hours sleep/night) have smaller, thinner and weaker bones than men who are not sleep deprived. Women who are sleep deprived have lower bone density than women who are not sleep deprived.
    • This is the first report of a relationship between sleep deprivation and bone health. Given the large number of sleep-deprived individuals, this may have important public health implications. These findings were published in the medical journal Osteoporosis International in 2007.
  • We found high heritability of bone measures among the Hutterite population, but it was different depending on the bone site (spine vs. hip vs. total body.) Percent time spent in moderate plus vigorous activity had the most notable effect on bone, but this effect depended on sex or age. For example, the benefit of activity on bone size was greater in men compared to women, but the benefit of activity on bone density was greater in older women compared to younger women and had a minimal effect among men.
    • These findings were published in the Journal of Bone and Mineral Research in 2007.
  • The food frequency questionnaire (FFQ) we are using in the follow-up study was found to estimate calcium intake based on the diet diaries we collected in the original study.
    • This is one of the first studies showing that the FFQ can be used in rural populations. These findings were published in the Journal of American Dietetic Association in 2007.
  • A subset of study participants used pedometers for 3 days. We found that people tend to underestimate how many miles per day they walk, especially young men. However, people who reported walking the most miles did in fact walk more than those who reported walking fewer miles.
    • Our conclusion from this study is that people can accurately classify themselves as to the amount of walking they do. These results were published in the Journal of Rural Health in 2008.
  • Studies that have looked at the relationship between age at puberty and bone health later in life are inconsistent. We looked at self-reported age at menarche and whether it was related to body fat and bone measures in adult women. We found that women with earlier menarcheal age had higher body fat and higher hip bone density than women with later menarcheal age.
    • These results were published in the American Journal of Human Biology in 2008.
  • We found that Hutterite children have higher bone density than non-Hutterite children. This difference is likely due to greater activity levels among Hutterite children.
    • These results emphasize the importance of childhood activity in optimizing bone health. These results were published in the international medical journal Bone in 2008.
  • Hutterites with hip and knee replacements due to osteoarthritis have higher bone density than Hutterites without joint replacements. The children and grandchildren of individuals with joint replacements also have higher bone density than the children and grandchildren of the individuals without joint replacement.
    • These results were published in the international medical journal Bone in 2009.
  • A greater gain in bone mass is observed in children who have greater gains in muscle mass. Children with greater fat gains have less bone gain and thinner bones than children with less gain in fat.
    • These results show the importance of muscle in determining bone health and the adverse effect of fat mass on bone health during growth. These results were published in the international Journal of Clinical Endocrinology and Metabolism in 2011.
  • Individuals who grew up on farms with low mechanization have higher bone density than individuals who grew up on farms that were highly mechanized.
    • Based on previous studies, we thought that activity during childhood and adolescence would be important for bone health later in life. We assumed that individuals raised on farms with low mechanization had greater activity levels as a child than individuals raised on highly mechanized farms. The results of this analysis were published in the international Journal of Musculoskeletal Neuronal Interactions in 2012. 
  • Men aged 39 years and younger had greater risk of falling than women of the same age, but there was no difference in risk between men and women aged 40 years and older. There was no difference between men and women in the risk of breaking a bone. Hutterites had lower risk of both falling and breaking a bone than non-Hutterites.
    • Other studies have shown lower fracture risk among rural populations, but we thought rural populations would be at greater risk of falling, and therefore breaking a bone, based on their higher activity levels. The results of this analysis were published in the medical journal Clinical Orthopedics and Related Research in 2015.
  • Rural (Hutterite and non-Hutterite) men had larger and stronger bones, and less bone loss in their 20’s and 60’s, than non-rural men. Population differences could not be explained by current activity levels or diet.
    • This study is one of the few studies that have shown that men in their early 20’s are already experiencing bone loss.  We did not find that current activity or diet could explain the population differences and we think these differences might be due to lifestyle differences earlier in life.  We are currently looking at sports participation in high school and college on these rates of change. The results of this analysis were published in the medical journal Bone in 2015.
  • In our previous work, we have found that Hutterites with hip and knee replacements due to osteoarthritis have higher bone density than those without joint replacements. The children and grandchildren of individuals with osteoarthritis also had higher bone density compared to children and grandchildren without osteoarthritis. 
    • We found that after growth, granddaughters and grandsons as well as daughters of individuals with osteoarthritis have greater volumetric bone density than individuals without osteoarthritis.  
    • During growth, granddaughters and grandsons of individuals with osteoarthritis have greater increases in their cortical (out shell of bone) bone mineral density than grandchildren of individuals without osteoarthritis. 
    • These, along with other findings, were published in the medical journal Clinical Orthopedics and Related Research in 2017. 
  • Men who participated in high school or college sports, or both, had greater hip bone mineral content (BMC) and density (aBMD) and larger bone size in the arm than men who did not participate in sports. The bone density was greater among men in their 20's, but due to greater rates of bone loss early in adulthood, the differences were no longer apparent by the mid-50's. 
    • These results indicate that there is a long-term benefit of high school and collegiate sports participation on bone density and size regardless of current physical activity, but the benefit does not persist at ages where osteoporosis is typically observed (60+ years of age).  
    • These findings were published in Calcified Tissue International in 2018.