Epidemiology of Osteoporosis

Abstract

Background:

India has a population capacity of 1.2 billion people. With a worldwide aging population, the prevention and management of osteoporosis has become a significant healthcare challenge. It is crucial to recognize the factors impacting poor bone health and appreciate the many hurdles to treat the disease to provide a better quality of life and decrease the financial burden on healthcare.

Purpose:

In this review article, we discuss the epidemiology of osteoporosis and address the definition, incidence, and prevalence, geographical variation in the occurrence of osteoporosis, and the risk factors for osteoporosis.

Methods:

Search terms using various combinations of the keywords 'osteoporosis,' 'epidemiology,' 'incidence,' 'prevalence,' 'fracture,' 'India,' 'world,' 'screening,' and 'FRAX' was done to review all relevant literature till June 2023.

Results & Conclusion:

India has a recent estimate of population capacity of 1.2 billion people. Various studies have revealed an osteoporosis prevalence in Indian women ranging from 8% to 62%. Poor dietary calcium intake, low vitamin D, and lifestyle changes contribute to osteoporosis.

Definition

The word “osteo-porosis” precisely means “porous” bone, implying a disruption of bone architecture and a reduction in bone mass density. It is often called the “silent disease or killer,” as it becomes clinically apparent only after a fracture occurs.

World Health Organization (WHO), in a consensus meeting in the early 1990s, defined osteoporosis as “a systemic skeletal disorder characterized by a low bone mass and by the microarchitectural deterioration of bone tissue, with a subsequent increase in bone fragility and susceptibility to fracture.”

The WHO definition of osteoporosis, based on Bone mineral density (BMD) measurements in white women (Table 1). The relative fracture risk increases 1.5–3 times for every standard deviation (SD) decrease in BMD. Ages 50 and older postmenopausal women and men are included in the WHO definition. These definitions are not intended to be used as treatment guidelines, but instead for estimating the prevalence of osteoporosis. The diagnostic classification should not be used for children, men younger than 50, and in pre-menopausal women.

Table 1.

Definition of osteoporosis

T-Score	Definition	Bone mineral density measurement (BMD) compared to normal mean for young-adult women
≥ − 1	Normal	Within 1 SD
− 1 < score < –2.5	Osteopenia (decreased bone mass)	− 1 to − 2.5 SD
≤ − 2.5	Osteoporosis	Less than ≥ − 2.5 SD
≤ − 2.5 (Fragility fracture)	Severe or “Established” osteoporosis	Less than ≥ − 2.5 SD and who has already experienced ≥ 1 fracture

SD standard deviation, T-score is patient’s bone density compared with young, healthy person of the same sex

BMD measurement has high specificity but low sensitivity. The current guidelines recommend integrating clinical risk factors and using BMD in decision-making about osteoporosis.

BMD scores are correlated with peak bone mass and bone loss. The Z-score is measurement of bone density compared to patients matched for age and sex, while T-score reflects the comparison of BMD of young subjects at their peak.

The diagnosis for osteoporosis in children, men younger than 50, and in pre-menopausal women should use Z scores adjusted for the race and their ethnicity. They can be sub-grouped as “within the expected-range-for-age” for scores above − 2.0, and “below the expected-range-for-age” for scores below − 2.0.

Epidemiology: The Regional Estimates

It is challenging to estimate the worldwide prevalence of osteoporosis. However, a systematic review [1] assessed the global prevalence of osteoporosis among people aged 15–105 years to be 18.3%. Worldwide, the prevalence of osteoporosis is reported higher in women 23.1 compared with 11.7 in men. The systematic review by Salari et al. pooled 86 studies. It included sixty-four studies from Asian countries, nine studies each from the USA and European countries, three in African population, and one in Australia to scan the prevalence of osteoporosis. This study's sample size was 103,334,579 individuals between the ages of 15 and 105. The adults aged 50 and older had a lower age-adjusted prevalence of osteopenia at the neck of the femur, the lumbar spine, or both (43.1%) than the adults aged 65 and above (47.5%). Among all adults and both age groups, osteopenia was more common among women than men. Osteoporotic fractures are a substantial burden to health care and are on the rise with longevity. [1].

Osteoporosis and India

India has a recent estimate of population capacity of 1.2 billion people. Based on recent growth patterns, the numbers will reach 1.4 billion (16% increase) by 2025 and 1.88 billion (34% increase) by 2050. The projected increase in life expectancy from the current 67 years to 71 years by 2025 and 77 years by 2050 [2].

Currently, only 10% (more than 100 million) of India's population are over 50 years. However, with the above estimates, 22% of the population in 2025 and 33% of the population in 2050 will be above the age of 50 years[2]. The recent studies estimate the prevalence of vitamin D deficient state in Indian Population to be as high as 80% and incidence of hip fractures a decade before than in western counterparts. Thus, the foremost concern for this aging population remains osteoporosis. According to estimates from 2013, 50 million people in India had T-scores of <  − 1. [3]. It suggested that 23 crore Indians over the age of 50 years in 2015 had osteoporosis. 20% of Indian women were osteoporotic. Numerous studies have revealed an osteoporosis prevalence in Indian women of various ages ranging from 8 to 62%.[2, 4, 5].

Factors Contributing to Osteoporosis in India

Low Calcium Intake

Children, teenagers, expectant and nursing mothers, and postmenopausal Indian women have all been found to have habitually poor calcium intakes. It is vital for Indian moms to reach their peak bone mass during the pubertal years. Given the added calcium needs through pregnancy, lactation, and the pre- and the post-menopausal years, the situation is severe. Given the data of people living under the poverty line in India, milk and milk products are expensive commodities. An additional factor that makes things worse is the inequitable milk and milk products distribution, with males receiving larger servings. A typical Indian diet is vegetarian, deprived of calcium, vitamin D, and other essential nutrients. The high proportionate of salt in the Indian diet can lead to calciuria. There are no national programs for bone health promotion or supplementation; nevertheless, national health programs offer 500 mg/d of calcium to the pregnant and breastfeeding mothers by consuming 165 g of food that has been fortified with micronutrients.

Indian diet, which is rich in phytates and oxalates, also retard the absorption of calcium. In addition, a large portion of the Indian populace enjoys drinking tea and coffee. Due to their low milk and high caffeine content, these drinks are responsible for decreasing BMD and raising the risk of fracture around hip joint.

Vitamin D Deficiency

Cultural differences and social and cultural reasons further contribute to vitamin D deficiency despite India being sun rich. Some of the contributing factors of hypovitaminosis D include avoiding sunlight exposure owing to sociocultural norms, inadequate calcium intake, and increased levels of 25(OH)-a d-24-hydroxylase enzyme among Indian population. A small portion of the Indian diet consists of oily fish and other foods that provide vitamin D. Less than 1% of vitamin D is obtained through dietary sources without food products being fortified with it (apart from oils having 5–15 g of vitamin D per 100 g of fat). Many pregnant and lactating mothers are Vitamin D deficient, which is passed on to their children. This can cause childhood rickets and decreased bone mass in adults, further paving osteoporosis in older age. Studies have documented that 80% of the urban population in India has Vitamin D deficiency (levels below 20 ng/ml) [6].

Lifestyle Changes

The slow urbanization of Indian Society amid Western influence has caused lifestyle changes, absence of physical activity, increased indoor living, and low exposure to sunlight. There is an increasing trend towards alcohol consumption, and smoking contributes to osteoporosis.

Poor Awareness

The general awareness of the population towards osteoporosis, its causes, and prevention is around 15%. Most populations with awareness have a positive family history. There is a need to increase awareness amongst the masses using Television, radio, newspaper, and local doctors about the disease.

Government Apathy

There is large-scale nutritional program to supplements Vitamin D and calcium among other vitamin supplementation targeting the school children. However, the osteoporosis is still not included in the national health priority.

Osteoporosis Around the World

Trends of Osteoporosis in the USA

Approximately one crore Americans over 50 suffer osteoporosis, with another 3.40 crore at risk of disease. 15 lakh Americans are suffering from osteoporotic fractures. Similar estimates have been reported for the UK, where osteoporosis affects one in two women and one in five males over the age of 50. These patients suffer from a lifetime risk of fragility fracture.

Prevalence of Osteoporosis in China

According to a cross-sectional study by wang et al. [7], the prevalence of osteoporosis among those aged 40 or older was significantly higher in women 20.6% (19.3–22.0%) compared to 5.0% (4.2–5.8%) among males. A total of 20,416 subjects were enrolled by the investigators for DEXA. For the spine radiography study, 8800 volunteers who were at least 40 years old were signed up. Men were reported to have a vertebral fracture prevalence of 10.5% (9.0–12.0%) and women to have a prevalence of 9.7% (8.2–11.1%). According to statistics, the prevalence of clinical fracture over the last 5 years was 4.1% (3.3–4.9%) for males and 4.2% (3.6–4.7%) for women. A fracture diagnosis based on bone mineral density resulted in 0.3% (0.0–0.7%) of women and 1.4% (0.8–2.0%) of men receiving anti-osteoporosis treatment to prevent fracture. The recognition of indicators linked to osteoporosis or fracture, including being overweight, and a longer sit-to-stand completion time, suggests that proper weight management and lowering the risk of falls may be attributed to a decreased fracture burden in Chinese population.

Section 2. (Epidemiological Trends in Treatment, Genome Mapping and Adherence to Osteoporosis Treatment)

Time Trends in Osteoporosis Treatment

Over time, the trends for the treatment of osteoporosis have witnessed a change. Today, bisphosphonates are the dominant drugs for the treatment of osteoporosis. Such is due to their proven efficacy and safety profile. Alendronate has been studied for its convenient dosing, efficacy, and safety. Hayes and colleagues examined trends in bisphosphonates initiation in Ontario, Canada, in a cross-sectional study over 20 years that reflects a policy change in the treatment of osteoporosis. The authors described that from 1996 unit 2005, most patients were started on cyclical etidronate therapy, thereafter weekly regimens took over. (risedronate—46%, alendronate—43%, etidronate—11%); The use increased significantly after the availability of the monthly and the delayed-release risedronate formulations. By 2015, majority of the patients were on risedronate (71%) followed by alendronate (28%), and etidronate (2%). The investigators also reported the trends in patient characteristics change over time. They reported an increase in initiation of bisphosphonate therapy among diabetics (men 14–22%, women 10–17%). However, the use of oestrogen hormone-based hormone replacement therapy has decreased (1996–2002 12% to 15% of women to 3% in 2008) and benzodiazepine (men 20 to 10%, women 22 to 13%), while the use of statins increased [8].

Adherence to osteoporosis medication is also one of the significant challenges for the treatment. Over time in a systematic review of 178 studies, in the study by Hesari et al. [9], there are five distinct approaches to test drug adherence for osteoporosis. Direct approaches, pharmacy records, questionnaires, electronic methods, and tablet counting constitute a few of these techniques. The medication possession ratio (MPR) is the adherence evaluation tool that is most frequently utilized, according to pharmacy statistics. The Morisky Medication Adherence Scale is the most popular questionnaire. The study reported direct and electronic methods as the most accurate methods for osteoporosis medication adherence. However, these methods are not used due to their high costs, so questionnaires are most commonly used [9].

The clinical evaluation of patients frequently takes a family history of osteoporotic fractures into account. In fact, solid evidence for the heredity of osteoporosis is provided by the observation of an elevated risk of fracture in a person with a positive parental history of hip fracture. Peak bone mass is also strongly influenced by genetic, racial, and ethnic characteristics. In most cases, a number of genetic and environmental variables interact to regulate the start and progression of osteoporosis; but, in a few rare instances, only one gene is responsible. Higher density genome-wide association studies have replaced traditional linkage mapping studies and candidate gene association studies as the preferred method for identifying the genetic causes of complex disorders like osteoporosis. More than 28 genes have been identified in the causation of osteoporosis per candidate gene association studies [10]. It has been suggested that polymorphism in the gene encoding for the vitamin D receptors is one of the determinant factors leading to lower BMD in Asian Indian Women compared to their Caucasian and Black counterparts. Several studies have described a possible correlation between oestrogen receptor alpha gene polymorphisms and vitamin D receptor gene polymorphisms with BMD in postmenopausal women.

Data availability

Not applicable.

Declarations

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical standard statement

This article does not contain any studies with human or animal subjects performed by the any of the authors.

Informed consent

For this type of study informed consent is not required.