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We have long recognized that our environment has a significant impact on our general health. Air pollution is known to contribute to respiratory conditions, poor cardiovascular outcomes, and certain kinds of cancer.
It’s increasingly important to identify factors that might contribute to suboptimal bone density and associated fracture risk in the population as a whole, and particularly in older adults. Aging is associated with a higher risk for osteoporosis and fractures, with their attendant morbidity, but individuals differ in their extent of bone loss and risk for fractures.
Known factors affecting bone health include genetics, age, sex, nutrition, physical activity, and hormonal factors. Certain medications, diseases, and lifestyle choices – such as smoking and alcohol intake – can also have deleterious effects on bone.
More recently, researchers have started examining the impact of air pollution on bone health.
As we know, the degree of pollution varies greatly from one region to another and can potentially significantly affect life in many parts of the world. In fact, the World Health Organization indicates that 99% of the world’s population breathes air exceeding the WHO guideline limits for pollutants.
Air pollutants include particulate matter (PM) as well as gases, such as nitric oxide, nitrogen dioxide, ammonia, carbon monoxide, sulfur dioxide, ozone, and certain volatile organic compounds. Particulate pollutants include a variety of substances produced from mostly human activities (such as vehicle emissions, biofuel combustion, mining, agriculture, and manufacturing, and also forest fires). They are classified not by their composition, but by their size (for example, PM1.0, PM2.5, and PM10 indicate PM with a diameter < 1.0, 2.5, and 10 microns, respectively). The finer the particle, the more likely it is to cross into the systemic circulation from the respiratory tract, with the potential to induce oxidative, inflammatory, and other changes in the body.
Many studies report that air pollution is a risk factor for osteoporosis. Some have found associations of lower bone density, osteoporosis, and fracture risk with higher concentrations of PM1.0, PM2.5, or PM10, even after controlling for other factors that could affect bone health. Some researchers have reported that although they didn’t find a significant association between PM and bone health, they did find an association between distance from the freeway and bone health – thus, exposure to polycyclic aromatic hydrocarbons and black carbon from vehicle emissions needs to be studied as a contributor to fracture risk.
Importantly, a prospective, observational study from the Women’s Health Initiative (which included more than 9,000 ethnically diverse women from three sites in the United States) reported a significant negative impact of PM10, nitric oxide, nitrogen dioxide, and sulfur dioxide over 1, 3, and 5 years on bone density at multiple sites, and particularly at the lumbar spine, in both cross-sectional and longitudinal analyses after controlling for demographic and socioeconomic factors. This study reported that nitrogen dioxide exposure may be a key determinant of bone density at the lumbar spine and in the whole body. Similarly, other studies have reported associations between atmospheric nitrogen dioxide or sulfur dioxide and risk for osteoporotic fractures.
Why the impact on bones?
The potential negative impact of pollution on bone has been attributed to many factors. PM induces systemic inflammation and an increase in cytokines that stimulate bone cells (osteoclasts) that cause bone loss. Other pollutants (gases and metal compounds) can cause oxidative damage to bone cells, whereas others act as endocrine disrupters and affect the functioning of these cells.
Pollution might also affect the synthesis and metabolism of vitamin D, which is necessary for absorption of calcium from the gut. High rates of pollution can reduce the amount of ultraviolet radiation reaching the earth which is important because certain wavelengths of ultraviolet radiation are necessary for vitamin D synthesis in our skin. Reduced vitamin D synthesis in skin can lead to poorly mineralized bone unless there is sufficient intake of vitamin D in diet or as supplements. Also, the conversion of vitamin D to its active form happens in the kidneys, and PM can be harmful to renal function. PM is also believed to cause increased breakdown of vitamin D into its inactive form.
Conversely, some studies have reported no association between pollution and bone density or osteoporosis risk, and two meta-analyses indicated that the association between the two is inconsistent. Some factors explaining variances in results include the number of individuals included in the study (larger studies are generally considered to be more reproducible), the fact that most studies are cross-sectional and not prospective, many do not control for other factors that might be deleterious to bone, and prediction models for the extent of PM or other exposure may not be completely accurate.
However, another recent meta-analysis reported an increased risk for lower total-body bone density and hip fracture after exposure to air pollution, particularly PM2.5 and nitrogen dioxide, but not to PM10, nitric oxide, or ozone. More studies are needed to confirm, or refute, the association between air pollution and impaired bone health. But accumulating evidence suggests that air pollution very likely has a deleterious effect on bone.
When feasible, it’s important to avoid living or working in areas with poor air quality and high pollution rates. However, this isn’t always possible based on one’s occupation, geography, circumstances, or economic status. Therefore, attention to a cleaner environment is critical at both the individual and the macro level.
As an example of the latter, the city of London extended its ultralow emission zone (ULEZ) farther out of the city in October 2021, and a further expansion is planned to include all of the city’s boroughs in August 2023.
We can do our bit by driving less and walking, biking, or using public transportation more often. We can also turn off the car engine when it’s not running, maintain our vehicles, switch to electric or hand-powered yard equipment, and not burn household garbage and limit backyard fires. We can also switch from gas to solar energy or wind, use efficient appliances and heating, and avoid unnecessary energy use. And we can choose sustainable products when possible.
For optimal bone health, we should remind patients to eat a healthy diet with the requisite amount of protein, calcium, and vitamin D. Vitamin D and calcium supplementation may be necessary for people whose intake of dairy and dairy products is low. Other important strategies to optimize bone health include engaging in healthy physical activity; avoiding smoking or excessive alcohol intake; and treating underlying gastrointestinal, endocrine, or other conditions that can reduce bone density.
Madhusmita Misra, MD, MPH, is the chief of the division of pediatric endocrinology, Mass General for Children; the associate director of the Harvard Catalyst Translation and Clinical Research Center; and the director of the Pediatric Endocrine-Sports Endocrine-Neuroendocrine Lab, Mass General Hospital, Boston.
A version of this article first appeared on Medscape.com.
We have long recognized that our environment has a significant impact on our general health. Air pollution is known to contribute to respiratory conditions, poor cardiovascular outcomes, and certain kinds of cancer.
It’s increasingly important to identify factors that might contribute to suboptimal bone density and associated fracture risk in the population as a whole, and particularly in older adults. Aging is associated with a higher risk for osteoporosis and fractures, with their attendant morbidity, but individuals differ in their extent of bone loss and risk for fractures.
Known factors affecting bone health include genetics, age, sex, nutrition, physical activity, and hormonal factors. Certain medications, diseases, and lifestyle choices – such as smoking and alcohol intake – can also have deleterious effects on bone.
More recently, researchers have started examining the impact of air pollution on bone health.
As we know, the degree of pollution varies greatly from one region to another and can potentially significantly affect life in many parts of the world. In fact, the World Health Organization indicates that 99% of the world’s population breathes air exceeding the WHO guideline limits for pollutants.
Air pollutants include particulate matter (PM) as well as gases, such as nitric oxide, nitrogen dioxide, ammonia, carbon monoxide, sulfur dioxide, ozone, and certain volatile organic compounds. Particulate pollutants include a variety of substances produced from mostly human activities (such as vehicle emissions, biofuel combustion, mining, agriculture, and manufacturing, and also forest fires). They are classified not by their composition, but by their size (for example, PM1.0, PM2.5, and PM10 indicate PM with a diameter < 1.0, 2.5, and 10 microns, respectively). The finer the particle, the more likely it is to cross into the systemic circulation from the respiratory tract, with the potential to induce oxidative, inflammatory, and other changes in the body.
Many studies report that air pollution is a risk factor for osteoporosis. Some have found associations of lower bone density, osteoporosis, and fracture risk with higher concentrations of PM1.0, PM2.5, or PM10, even after controlling for other factors that could affect bone health. Some researchers have reported that although they didn’t find a significant association between PM and bone health, they did find an association between distance from the freeway and bone health – thus, exposure to polycyclic aromatic hydrocarbons and black carbon from vehicle emissions needs to be studied as a contributor to fracture risk.
Importantly, a prospective, observational study from the Women’s Health Initiative (which included more than 9,000 ethnically diverse women from three sites in the United States) reported a significant negative impact of PM10, nitric oxide, nitrogen dioxide, and sulfur dioxide over 1, 3, and 5 years on bone density at multiple sites, and particularly at the lumbar spine, in both cross-sectional and longitudinal analyses after controlling for demographic and socioeconomic factors. This study reported that nitrogen dioxide exposure may be a key determinant of bone density at the lumbar spine and in the whole body. Similarly, other studies have reported associations between atmospheric nitrogen dioxide or sulfur dioxide and risk for osteoporotic fractures.
Why the impact on bones?
The potential negative impact of pollution on bone has been attributed to many factors. PM induces systemic inflammation and an increase in cytokines that stimulate bone cells (osteoclasts) that cause bone loss. Other pollutants (gases and metal compounds) can cause oxidative damage to bone cells, whereas others act as endocrine disrupters and affect the functioning of these cells.
Pollution might also affect the synthesis and metabolism of vitamin D, which is necessary for absorption of calcium from the gut. High rates of pollution can reduce the amount of ultraviolet radiation reaching the earth which is important because certain wavelengths of ultraviolet radiation are necessary for vitamin D synthesis in our skin. Reduced vitamin D synthesis in skin can lead to poorly mineralized bone unless there is sufficient intake of vitamin D in diet or as supplements. Also, the conversion of vitamin D to its active form happens in the kidneys, and PM can be harmful to renal function. PM is also believed to cause increased breakdown of vitamin D into its inactive form.
Conversely, some studies have reported no association between pollution and bone density or osteoporosis risk, and two meta-analyses indicated that the association between the two is inconsistent. Some factors explaining variances in results include the number of individuals included in the study (larger studies are generally considered to be more reproducible), the fact that most studies are cross-sectional and not prospective, many do not control for other factors that might be deleterious to bone, and prediction models for the extent of PM or other exposure may not be completely accurate.
However, another recent meta-analysis reported an increased risk for lower total-body bone density and hip fracture after exposure to air pollution, particularly PM2.5 and nitrogen dioxide, but not to PM10, nitric oxide, or ozone. More studies are needed to confirm, or refute, the association between air pollution and impaired bone health. But accumulating evidence suggests that air pollution very likely has a deleterious effect on bone.
When feasible, it’s important to avoid living or working in areas with poor air quality and high pollution rates. However, this isn’t always possible based on one’s occupation, geography, circumstances, or economic status. Therefore, attention to a cleaner environment is critical at both the individual and the macro level.
As an example of the latter, the city of London extended its ultralow emission zone (ULEZ) farther out of the city in October 2021, and a further expansion is planned to include all of the city’s boroughs in August 2023.
We can do our bit by driving less and walking, biking, or using public transportation more often. We can also turn off the car engine when it’s not running, maintain our vehicles, switch to electric or hand-powered yard equipment, and not burn household garbage and limit backyard fires. We can also switch from gas to solar energy or wind, use efficient appliances and heating, and avoid unnecessary energy use. And we can choose sustainable products when possible.
For optimal bone health, we should remind patients to eat a healthy diet with the requisite amount of protein, calcium, and vitamin D. Vitamin D and calcium supplementation may be necessary for people whose intake of dairy and dairy products is low. Other important strategies to optimize bone health include engaging in healthy physical activity; avoiding smoking or excessive alcohol intake; and treating underlying gastrointestinal, endocrine, or other conditions that can reduce bone density.
Madhusmita Misra, MD, MPH, is the chief of the division of pediatric endocrinology, Mass General for Children; the associate director of the Harvard Catalyst Translation and Clinical Research Center; and the director of the Pediatric Endocrine-Sports Endocrine-Neuroendocrine Lab, Mass General Hospital, Boston.
A version of this article first appeared on Medscape.com.
We have long recognized that our environment has a significant impact on our general health. Air pollution is known to contribute to respiratory conditions, poor cardiovascular outcomes, and certain kinds of cancer.
It’s increasingly important to identify factors that might contribute to suboptimal bone density and associated fracture risk in the population as a whole, and particularly in older adults. Aging is associated with a higher risk for osteoporosis and fractures, with their attendant morbidity, but individuals differ in their extent of bone loss and risk for fractures.
Known factors affecting bone health include genetics, age, sex, nutrition, physical activity, and hormonal factors. Certain medications, diseases, and lifestyle choices – such as smoking and alcohol intake – can also have deleterious effects on bone.
More recently, researchers have started examining the impact of air pollution on bone health.
As we know, the degree of pollution varies greatly from one region to another and can potentially significantly affect life in many parts of the world. In fact, the World Health Organization indicates that 99% of the world’s population breathes air exceeding the WHO guideline limits for pollutants.
Air pollutants include particulate matter (PM) as well as gases, such as nitric oxide, nitrogen dioxide, ammonia, carbon monoxide, sulfur dioxide, ozone, and certain volatile organic compounds. Particulate pollutants include a variety of substances produced from mostly human activities (such as vehicle emissions, biofuel combustion, mining, agriculture, and manufacturing, and also forest fires). They are classified not by their composition, but by their size (for example, PM1.0, PM2.5, and PM10 indicate PM with a diameter < 1.0, 2.5, and 10 microns, respectively). The finer the particle, the more likely it is to cross into the systemic circulation from the respiratory tract, with the potential to induce oxidative, inflammatory, and other changes in the body.
Many studies report that air pollution is a risk factor for osteoporosis. Some have found associations of lower bone density, osteoporosis, and fracture risk with higher concentrations of PM1.0, PM2.5, or PM10, even after controlling for other factors that could affect bone health. Some researchers have reported that although they didn’t find a significant association between PM and bone health, they did find an association between distance from the freeway and bone health – thus, exposure to polycyclic aromatic hydrocarbons and black carbon from vehicle emissions needs to be studied as a contributor to fracture risk.
Importantly, a prospective, observational study from the Women’s Health Initiative (which included more than 9,000 ethnically diverse women from three sites in the United States) reported a significant negative impact of PM10, nitric oxide, nitrogen dioxide, and sulfur dioxide over 1, 3, and 5 years on bone density at multiple sites, and particularly at the lumbar spine, in both cross-sectional and longitudinal analyses after controlling for demographic and socioeconomic factors. This study reported that nitrogen dioxide exposure may be a key determinant of bone density at the lumbar spine and in the whole body. Similarly, other studies have reported associations between atmospheric nitrogen dioxide or sulfur dioxide and risk for osteoporotic fractures.
Why the impact on bones?
The potential negative impact of pollution on bone has been attributed to many factors. PM induces systemic inflammation and an increase in cytokines that stimulate bone cells (osteoclasts) that cause bone loss. Other pollutants (gases and metal compounds) can cause oxidative damage to bone cells, whereas others act as endocrine disrupters and affect the functioning of these cells.
Pollution might also affect the synthesis and metabolism of vitamin D, which is necessary for absorption of calcium from the gut. High rates of pollution can reduce the amount of ultraviolet radiation reaching the earth which is important because certain wavelengths of ultraviolet radiation are necessary for vitamin D synthesis in our skin. Reduced vitamin D synthesis in skin can lead to poorly mineralized bone unless there is sufficient intake of vitamin D in diet or as supplements. Also, the conversion of vitamin D to its active form happens in the kidneys, and PM can be harmful to renal function. PM is also believed to cause increased breakdown of vitamin D into its inactive form.
Conversely, some studies have reported no association between pollution and bone density or osteoporosis risk, and two meta-analyses indicated that the association between the two is inconsistent. Some factors explaining variances in results include the number of individuals included in the study (larger studies are generally considered to be more reproducible), the fact that most studies are cross-sectional and not prospective, many do not control for other factors that might be deleterious to bone, and prediction models for the extent of PM or other exposure may not be completely accurate.
However, another recent meta-analysis reported an increased risk for lower total-body bone density and hip fracture after exposure to air pollution, particularly PM2.5 and nitrogen dioxide, but not to PM10, nitric oxide, or ozone. More studies are needed to confirm, or refute, the association between air pollution and impaired bone health. But accumulating evidence suggests that air pollution very likely has a deleterious effect on bone.
When feasible, it’s important to avoid living or working in areas with poor air quality and high pollution rates. However, this isn’t always possible based on one’s occupation, geography, circumstances, or economic status. Therefore, attention to a cleaner environment is critical at both the individual and the macro level.
As an example of the latter, the city of London extended its ultralow emission zone (ULEZ) farther out of the city in October 2021, and a further expansion is planned to include all of the city’s boroughs in August 2023.
We can do our bit by driving less and walking, biking, or using public transportation more often. We can also turn off the car engine when it’s not running, maintain our vehicles, switch to electric or hand-powered yard equipment, and not burn household garbage and limit backyard fires. We can also switch from gas to solar energy or wind, use efficient appliances and heating, and avoid unnecessary energy use. And we can choose sustainable products when possible.
For optimal bone health, we should remind patients to eat a healthy diet with the requisite amount of protein, calcium, and vitamin D. Vitamin D and calcium supplementation may be necessary for people whose intake of dairy and dairy products is low. Other important strategies to optimize bone health include engaging in healthy physical activity; avoiding smoking or excessive alcohol intake; and treating underlying gastrointestinal, endocrine, or other conditions that can reduce bone density.
Madhusmita Misra, MD, MPH, is the chief of the division of pediatric endocrinology, Mass General for Children; the associate director of the Harvard Catalyst Translation and Clinical Research Center; and the director of the Pediatric Endocrine-Sports Endocrine-Neuroendocrine Lab, Mass General Hospital, Boston.
A version of this article first appeared on Medscape.com.