Dietary Calcium Intake and HPV Infection Status Among American Women: A Secondary Analysis from National Health and...

BACKGROUND The evidence on the link of dietary calcium (DCa) to human papillomavirus (HPV) infection is limited. Thus, this research was conducted to explore whether DCa is independently associated with HPV infection status in American women with age of 18 to 59 years old. MATERIAL AND METHODS We performed a secondary analysis from the National Health and Nutrition Examination Survey (NHANES) data set including 7 cycles from 2003 to 2016. A total of 13 475 selected participants were used for data analysis. The interested independent and the outcome variable were DCa and HPV infection status (HPV infection; HPV subtype). Sociodemographic, dietary, laboratory, questionnaire, and physical examination data were covariates. Weighted binary logistic regression and generalized additive model (GAM) were used for the investigation of both linear and non-linear relationships between DCa and HPV infection status. RESULTS Weighted multivariable binary logistic regression indicated DCa was not associated with HPV infection and subtype (OR: 0.93; 95% CI: 0.82-1.05 for HPV infection; OR: 1.09; 95% CI: 0.93-1.28 for HPV subtype). For HPV infection, a non-linear correlation was detected, whose inflection points were 9.78 of log2 DCa. The OR values and the confidence intervals on both sides of inflection point were 0.83 (95% CI: 0.70-0.98) and 1.18 (95% CI: 0.91-1.52), respectively. CONCLUSIONS At the range of 3.32-9.78 of log2 calcium intake, DCa intake was negatively correlated with HPV infection. After this interval, DCa intake was not associated with the risk of HPV infection.