Clinical Context

Osteoporosis is a metabolic bone disease characterized by decreased BMD and increased risk for fragility fractures, leading to reduced quality of life and increased morbidity and mortality. Of approximately 30% of postmenopausal women with osteoporosis in the United States, 40% develop fragility fractures.

Triclosan -- a chemical found in toothpaste, soaps, hand sanitizers, and mouthwash -- has been shown in laboratory studies to increase interstitial collagen accumulation and trabecular bone, but any associations between TCS exposure and human bone health were previously undetermined. The goal of this study was to examine the association of BMD and osteoporosis with urinary TCS concentrations in US women participating in the 2005-2010 NHANES.

Study Synopsis and Perspective

Women who have high levels of the antibacterial agent TCS in their urine have worse bone health than other women, new research indicates.

Triclosan, which was recently banned in hand sanitizers, is used in a variety of "consumer goods and personal care products including soaps, hand sanitizers, toothpaste, and mouthwash," Shaofang Cai, the Second Affiliated Hospital of Xiamen Medical College, China, and colleagues explained in their article, published online June 25 in the Journal of Clinical Endocrinology and Metabolism.^[1]

In animal studies, TCS has been found to disrupt hormone activity, and in laboratory studies of cell lines, it has caused interstitial collagen accumulation and an increase in trabecular bone.

Still, "as far as we know, this is the first epidemiological study to investigate the association [of TCS] exposure with [BMD] and osteoporosis," senior author Yingjun Li, PhD, Hangzhou Medical College School of Public Health, China, said in a statement from the Endocrine Society.

The group analyzed data from more than1800 adult women who participated in the 2005-2010 US NHANES. Among women in the highest tertile of urinary TCS level, BMD was lower in the total femur, intertrochanter, and lumbar spine, and the prevalence of osteoporosis in the intertrochanter was more than 2-fold higher.

"We provided the first evidence," they reported, "that urinary TCS concentration was significantly associated with BMD and osteoporosis in... US adult women."

The researchers cautioned that this was an observational study and so cannot show cause and effect.

Triclosan Detected in 75% of the Population

People are exposed to TCS, Cai and colleagues said, from consumer products, the water supply, or animal or food products.

In 2003 and 2004, about 75% of the US population had detectable levels of TCS in their urine. Levels ranged from 7.9 nmol/L to 13.1 μmol/L.

In September 2016, the US Food and Drug Administration (FDA) banned TCS in consumer antiseptic washes, and in December 2017, it banned it in healthcare antiseptics. The FDA took these actions after it determined that manufacturers had not demonstrated that TCS was "generally recognized as safe and effective" when added to these products.

Most recently, on April 12, 2019, the FDA issued a final rule banning TCS from consumer hand sanitizers, effective April 13, 2020; however, as noted in an FDA consumer update on May 16, 2019,^[2] "[TCS] can be found in many places today. It has been added to many consumer products -- including clothing, kitchenware, furniture, and toys -- to prevent bacterial contamination.

"Because of that, people's long-term exposure to [TCS] is higher than previously thought, raising concerns about the potential risks associated with the use of this ingredient over a lifetime," according to the FDA consumer update.

In a 2007 study published by Clinical infectious Diseases, drug resistance as a potential risk identified with TCS and there was no additional health benefit identified with soap containing TCS compared with regular soap.

Does Triclosan Exposure Affect Bone Health?

Cai and colleagues investigated the association among TCS, BMD, and osteoporosis in American women.

They identified 1848 women age 20 years or older for whom values regarding these 3 measures were available from 3 recent NHANES surveys.

The researchers measured BMD using dual-energy x-ray absorptiometry scans of 4 femoral regions -- total femur, femur neck, trochanter, intertrochanter -- and the lumbar spine. They diagnosed osteoporosis according to BMD results at any of the 4 femoral regions.

The investigators assessed urinary TCS from a spot urine sample using high-performance liquid chromatography-tandem mass spectrometry, the lower limit of detection of which was 2.3 ng/mL.

The mean age of the women was 48±0.5 years. Most (72%) were non-Hispanic white; the rest were black (11%), Mexican American (7%), or of other race/ethnicity (10%).

About half (909 women) were postmenopausal (mean age, 62±0.5 years). The mean age of the other women was 36±0.4 years.

The women were divided into tertiles on the basis of urinary TCS level.

After adjustment for multiple variables (ie, age, race, education, marital status, smoking, body mass index [BMI], physical activity, calcium intake, diabetes, hormone use, and menopause), compared with women in the lowest tertile of urinary TCS level, women in the highest tertile were more likely to have a lower mean BMD at the total femur (β=−0.016), intertrochanter (β=–0.022), and lumbar spine (β=–0.014). These associations were stronger in postmenopausal women.

After multivariable adjustment, overall, compared with women in the lowest tertile of urinary TCS level, women in the highest tertile were more than twice as likely to have osteoporosis in the intertrochanter (odds ratio [OR]=2.46 [95% CI: 1.19, 5.105]).

Among premenopausal women, there were 3 cases of osteoporosis in the total femur, 5 in the femur neck, 2 in the trochanter, and 4 in the intertrochanter.

The study received funding from the National Natural Science Foundation of China and the Medical Science and Technology Project of Zhejiang Province. The authors have disclosed no relevant financial relationships.

Clinical Implications

• Among US women, urinary TCS concentration was significantly associated with lower BMD and higher prevalence of osteoporosis in US women, particularly in postmenopausal women.
• Exposure to TCS may come from consumer products, water supply, or animal or food products, and approximately three-quarters of the US population had detectable urinary TCS in 2003 and 2004.
• Implications for the Healthcare Team: TCS is still used in clothing, kitchenware, furniture, toys, and other consumer products, and long-term exposure is therefore higher than previously thought, raising concerns about potential lifetime risks. Health care professionals should advice that studies have found “no additional health benefit” in the inclusion of TCS in consumer products.

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