Influence of the natural hormonal milieu on brain and behavior in women who smoke cigarettes: Rationale and methodology

Impact of the natural hormonal milieu on ventral striatal responses to appetitive cigarette smoking cues: A prospective longitudinal study

Background

The female sex hormones estradiol (E) and progesterone (P) galvanize the ventral striatal reward pathway. E elevates ventral striatal dopamine and accelerates drug-cued reinstatement, while P has opposing 'protective' effects on drug-related behavior. We hypothesize that women may exhibit greater ventral striatal responses to smoking cues (SCs) during the late follicular phase of the menstrual cycle (MC) when E is high and unimpeded by P, and reduced responses during the late luteal phase when P is high.

Methods

To test our hypothesis, 24 naturally cycling cigarette-dependent women completed functional magnetic resonance (fMRI) sessions over the course of 3 MCs at select time points to reflect the early follicular (low E and P; LEP, control condition), late follicular (high E, low P; HE) and mid-luteal (high E, high P; HEP) MC phases. During fMRI sessions (counterbalanced by phase), women were exposed to a SC versus nonSC audio-visual clip. Ovulation was verified for each MC, and hormone levels were acquired prior to sessions.

Results

Contrasts within conditions showed that ventral striatal brain responses to SCs versus nonSCs were negligible during LEP and greater during HE (p=0.009) and HP (p=0.016). Contrasts across conditions showed that HE and HEP had greater responses than LEP (p=0.005), and HE had greater responses than HEP (p=0.049).

Conclusions

Results support and extend our retrospective cross-sectional study of the influence of the hormonal milieu on SC reactivity. Results are clinically relevant as they may guide novel, hormonally-informed and immediately translatable treatment strategies that can potentially reduce relapse in naturally cycling women.

Different effects of smoking on atopic and non-atopic adult-onset asthma

BACKGROUND

Both tobacco smoking and atopy increase the risk of adult-onset asthma. We studied if there are differences in the effects of smoking on the risks of atopic and non-atopic adult-onset asthma, and if gender modifies these effects.

METHODS

The Finnish Environment and Asthma Study (FEAS) includes 521 incident cases of adult-onset asthma and 932 population-based controls, aged 21 to 63 years, recruited from a geographically defined area of Pirkanmaa, South Finland. Asthma was defined based on symptoms and lung function measurements, atopy by IgE antibodies to common aeroallergens and smoking by the study questionnaire.

RESULTS

Altogether 212 cases were atopic, and 251 cases were non-atopic. Regular smoking increased the risk of atopic asthma (adjusted OR 1.24, 95% CI 0.83-1.85), this effect was seen in women (aOR 1.77, 1.06-2.95) but not in men (aOR 0.75, 0.39-1.45). Among regular smokers, the amount smoked was lowest among women with atopic asthma. Recent quitting of smoking was related to increased risk of both atopic (aOR 4.91, 2.26-10.65) and non-atopic (aOR 4.37, 1.87-10.21) asthma. Having quitted smoking over a year ago was related to increased risk of non-atopic asthma (aOR 1.57, 1.08-2.28), mainly in men (aOR 2.03, 1.06-3.88).

CONCLUSIONS

In women, rather small amounts of regular smoking increase the risk of atopic asthma. However, for non-atopic asthma, the smoking induced risk continues for longer after quitting, especially in men. In conclusion, the effects of smoking on the risks of atopic and non-atopic asthma differ, and gender modifies these effects.