Perimenopausal transdermal estradiol replacement reduces serum HDL cholesterol efflux capacity but improves cardiovascular risk factors

•The cardiovascular effects of hormone replacement therapy are uncertain.•The impact of transdermal estradiol on alternative HDL-based metrics is unknown.•Transdermal estradiol reduced HDL cholesterol efflux capacity.•Transdermal estradiol also led to a shift toward increased HDL particle size.•Transdermal estradiol improved major cardiovascular risk factors including LDL-C.